SOLAR PHOTOVOLTAIC PANELS, A NEW SOURCE OF

LIABILITY FOR BUILDING SURVEYORS

by

ERNESTO CORREA A Masters Dissertation Presented to Sheffield Hallam University

Faculty of Development and Society

4 September 2015

In Partial Fulfilment of the Requirement for the Degree of MSc in

Building Surveying

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Acknowledgements:

The authors would like to express gratitude and consideration to all the people

who made this work possible

A big thank to my supervisor: John Grant; lecturer and researcher at Hallam

University, for his invaluable guidance and patience.

Thanks to my wife Marta for her support and encouragement, my daughters

Guillermina and Martina. To my ant Teresa for her always prompt assistance.

Thanks to Dr Graham Smith for his critics and advice.

Andrew Winters (Blundells)

Robin Atherton (Mack Solar)

Phil Parnham (Blue Box partners)

Another thank to the following contributors:

My neighbours Gerry and Sue for their always helpful comments

Anne Dussart

to all the households from S17, S7 and S8, in Sheffield, for their generosity on

completing the questionnaires from which this work have been produced and

became reality.

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ABSTRACT

This study analyses the effects and benefits of PV solar panel installations in

domestic premises, gathering information from households who adopted this

innovative technology. It emphasizes the motivations to adopt the technology

and its consequences.

The motivation of the study comes from reviewing the current state of literature

on the evolution of solar panel industry in England compared to the EU.

Following the steps of Morris-Marsham (2010) a user survey questionnaire was

developed in order to obtain most of the data, and this was used to interview

households which had fitted their roofs with solar or thermal panels in Sheffield

(post codes S17, S7 and S8) from 2010.

The outcome has revealed that in the majority of cases the incentive from the

Feed in Tariff scheme has been the driving force to invest in this technology.

There was a certain rush from stakeholders to secure the budget available from

the government, disregarding the structural issues generated by the installation.

This work comes to the conclusion that it is important for surveyors to be aware

that a number of houses are prone to have defects on their roofs, due to the

lack of sufficient strength on the existent structure to support the extra weight –

dead and live loads. The author also noted problems with poor installations due

to deficiency in following the current MCS installation guidance.

Households should to be informed about the importance of having an

exhaustive assessment regarding the roof loading capacity before installing the

devices, and inform their insurers once the fitting has taken place.

Local authorities will need to get involved in creating a precise framework for

users and to legislate for when decommissioning of the systems takes place.

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CONTENTS

1. Introduction ………………………………………………………………………….1

1.1 Aims…………….1

1.2 Objectives………….…….1

1.3 Context…………………..2

1.4 Surveyors Concerns……2

1.5 Main Questions for Hypothesis………....3

1.6 Hypotheses………………4

2. Research Methodology .................................................................................4

2.1 Methodology ………....5

2.2 Questionnaires …………..7

2.3 Distribution Map ……..8

2.4 Interviews …………….…10

2.5 Interviews to Homeowners Map …….....11

2.6 Outlines from Chapter……….12

2.7 Limitations ………………12

3. Literature Review ………………………………………………………………….13

3.1 Aims of the Chapter….....13

3.2 History ………………13

3.3 List of Sources…………..13

3.4 Chapter Conclusion ……….30

4. Survey and Findings…………………..………………………….……………….31

4.1 Answers to Questionnaires ….…..31

Q.1 Does the occupier have a solar array? ............31

Q.2 Did you install the panels? .....……. 32

Q.3 Is this a solar panel system?......................33

Q.4 How far did the following factors? ….. 35

Op A Households are able to use the energy…………36

Op B Being able to use the energy………..37

Op C Being environmentally friendly……………38

Op D Other considerations …………….39

Q.5 Does the occupier believe he received a good advice? ............ 40

Q.6 Improvements to the property ……………..41

Q.7 Quality of inspection by the installer ……………… 42

Q.8 Reinforcement from the roof structure …… 43

Q.9 Effects of the wind …………44

Q.10 Renting out the roof space ………….45

Q.11 Taking advantage from the FiTs ……………46

Q.12 Renting out to a solar company …….47

Q.13 Influence from the FiTs …………48

Q.14 Consideration of the years to live in the property ……. 49

Q.15 The home insurance covering the systems at no cost ………. 50

Q.16 Buying another insurance or increasing the cover …………………….51

Q.17 Influence from the solar array in the final ………………52

Q.18 Feeling satisfied with the system …………… 53

Q.19 Efficiency from the system ……………………………….54

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Q.20 Selling a property with a lease …………………..55

Q.21 Replacing or increasing the solar array ……………………56

4.2 Interview to Homeowners …………………….57

4.3 Interview to MRICS Valuer……….64

4.4 Interview to Solar Panel Installer…………....65

4.5 Interview to Building Surveyor…..........65

4.7 The Authors Findings….............

5. Results …………………………………………………………………………………64

5.1 Answering the Hypothesis …………………..65

6. Conclusions ………………………………………………………………………......66

7. Summary……………………………………………………………………………….66

8. Suggestions and further study ……………………………………………………67

9. Appendix ………………………………………….1

9.1 Questioners for Householders Layout ……………………2

9.2 Short Interviews for Householders …………..3

Manuscripts from verbal responses …………………..7

9.3 Interview to Andrew Winters (Blundells) ………………………...22

Layout and Summary …………………………………………………………24

9.4 Interview to Robin Atherton …………………….…………27

(Mack Construction) Summary …………………………………….28

9.5 Interview to Phil Parnham (Blue Box Partners) ………………………….….31

Layout and Summary …………………………….33

9.6 Other consultations …………………….35

10. References

Charts

Chart 1: Number of Questionnaires Delivered ………9

Chart 2: Total Interviews among S17, S7 and S8 ………………11

Chart 3: Existence of a working solar array …………31

Chart 4: Installing the solar array or buying it with the property ………..32

Chart 5: Type of system ………………………………..34

4.1.4.1 Q.4, Option (A) from question 4 Chart 6: Use energy as is produced …36

4.1.4.2 Q.4, Option (B) from question 4 Chart 7: Able to use electricity ….37

4.1.4.3 Q.4, Option (C) from question 4 Chart 8: environmentally friendly …38

4.1.4.4 Q.4, Option (D) from question 4 Chart 9: Other considerations .39

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Chart 10: Advice at the time to purchase………………………...40

Chart 11: Improvements …………………….….41

Chart 12: Satisfaction……………………………………………….42

Chart 13: Roof reinforcing…………………………………………………………..…43

Chart 14: Wind effect issues ………………………………..44

Chart 15: renting out the roof area ……………………………………….….45

Chart 16: Taking advantage from Fits …………………………..46

Chart 17: Renting out to a solar supplier ………………………………………..47

Chart 18: Influence of the FiTs ………………………………..48

Chart 19: Thinking ahead…………………………….49

Chart 20: Insurance covering ……………………………………………...50

Chart 21: Necessity to purchase insurance …………………………51

Chart 22: expectation of better value …………………………………………………………..52

Chart 23: Level of satisfaction ……………………………………..….53

Chart 24: Efficiency ………………………………….…54

Chart 25: Types of ownership ……………………………………….55

Chart 26: Replacing or increasing covering ………………………………………………..56

Figures

Fig 1: Digimap.edina.ac.uk/roam/os, 2015……………..8

Fig. 2: Interview to Homeowners………………9

(Mapping Idea from: Morris-Marsham Report p.18) ……………...11

Fig. 3: Sky Flair Ltd (2015) Evacuated tube collector: ……………………..19

Fig. 4: The Green Home (2015) Flat plate collector: ………………..…20

Fig. 5: Combined images from: P 3.4.7.c: Dow Corning (2015) &

P 3.4.7.d: Pearl Solar Panels (2015) …………………………..……………21

Fig.6: BRE Digest (2004 p.3) ………………………..22

Fig.7: Cortez Colorado (2015) Fink-truss Image [online] …………………………………..23

Fig 8: Truss Corp (2015) Prefabricated Roof Truss [online] ………..……23

Fig 9: VIRIDIANSOLAR (2014) Blowing in the Wind? In-roof PV panel examples ……………………...29

Fig 11: Solar Panel Unit, (Own Image) ……………………………..…..33

Fig 12: Solar Thermal Collector (Own Image)……….…33

Fig. 13: Questionnaire responses. …………………………………………….. 59

Fig. 14: Questionnaire responses. …………………69

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Tables

Table 1: Type of installations ……………………..8

Table 2: Rates responses …………………………………..…..9

Table 2 a Interview to homeowners .………………………………………………….……..11

Table 3: Ridal et al (2010) BRE & Waterman Group…………………...22

Table 4: Figures from the responses A; B and C: …………………………………35

Table 5: Option D: People created the options

from what they considered important, these are the figures: …………………………………………………….36

Table 6: Improvements …………………………………………….….41

Table 7: Roof assessment …………………………42

Table 8: Responses from questions 1 to 5 …………………………..58

Table 9: Responses from questions 7 to 12 ……………………………………………58

Table 10: …………………………………………….……..51

Pictures

Own Images

1Own graphic 1: People involved in the Problem: …………………...…5

2 Own Diagram, common interest…………………………….10

Diagram 3: Own Diagram obtained from the Zapfe study ………………………..……..28

Property A, Pict 1 West facing view………………..……61

Pict 2 In detail …………………….…61

Pict 3 Sagging process ……………………………..………………..61

Pict 4 Damage in detail………………………..……61

Property B, Pict 1 ………………………62

Pict 2 ……………………………………………….…62

Pict 3 Cantilevered panels ……………………………….…….62

Property C, Pict 1…………….63

Pict 2 In detail…………63

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Abbreviations

RICS Royal Institute of Charted Surveyors

LCT Low Carbon Technologies

FiTs Feed In Tariff Scheme

MCS Microgeneration Certification Scheme

EA2008 Energy Act 2008

PV Photovoltaic

PVsp Photovoltaic Solar Panel

PVtp Photovoltaic Thermal Panel

UKPVS United Kingdom Photovoltaic Strategy

AD. A Approved Document A

BS British Standard

HI Home Insurance

HBRs Home Buyers Report

SAP Government’s Standard Assessment Procedure

MIS3002 Microgeneration Installation Standard 3002

RE Renewable Energy

SPI Solar Panel Inverter

DECC Department of Energy and Climate Change

CPS Competent Persons Scheme

EE Energy Efficiency

EPC Energy Performance Certificate

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Chapter 1- Introduction

1.1 Aims

Professionals from building surveying operate in a housing market where properties will

be purchased and sold with the attachment of different technological elements (e.g.

Wind turbine, Solar Panels, Ground Source Heat Pumps etc.)

The aim of the study is to provide building surveyors and other building professionals

with a reference check list about how homeowners perceive PVsp (Photovoltaic Solar

Panels) and PVtp technology and which are the pitfalls in terms of advice prior to

installing those systems. In addition, the study also explores the real motivation for

purchasing the panels and how people deal with those systems on a daily basis.

The author’s strategy is to gather information directly from the source, inviting the

householders to participate in the study where they can express their experiences.

While we must recognise that Feed in Tariff Schemes (FiTs) have been a good

reason for people to invest in solar panels, there must be other motivations driving the

rapid growth in the industry during the last 4 years.

Energy saving is presently a mainstream topic, but individuals reasons for adopting the

technology can only be answered by the homeowners who installed the systems. Their

unbiased responses describe the benefits of the system in terms of bills reductions,

panel performance, workmanship of installers and the household’s expectations

1.2 Objectives

The author’s hypothesis aligned with the actual users’ responses that their investment

was the main reason for panel installation; however, it is also the case that customers

had not encountered any inconvenience with the equipment. The survey examines a

particular area in Sheffield where a significant number of households have installed

PVsp and PVtp devices.

We want to know if householders made some extra investment or improvement to their

properties before the installation took place. For example, the author asked if the roof

has been reinforced in order to bear additional loads.

Final results explore homeowner’s knowledge from the current legal framework. They

were invited to explain how they might deal with the hypothetical sale of their property

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and the best way to transfer the systems to the next owner. The questionnaire

introduces most of the issues that may appear during the lifespan of the system.

Results will shape the conclusions from which surveyors can take advantage

augmenting their own experiences.

1.3 Context

Perhaps the last 5 years have been the most stimulating times for the energy market

(British Gas, 2015). Consumers have become small generators of electricity.

Homeowners concerned by the high cost of energy and other factors such as impact

on the environment started to look for alternatives and the EA2008 produced the

appropriated frame for renewable energies. The consequence of this bill was the Feed

in Tariff scheme, a policy that came into force in April of 2010; this is an incentive for

households to invest in PV solar installations and other sources of energy, with the

promise of a 20 year payment plan for the electricity they can produce plus another

sum of money for the energy they can export back to the national grid. (HM

Government, Energy Act 2008).

Studies over properties with PV solar panel installations are mainly concentrated to

advertise a particular system, or to measure customer satisfaction surveys from

installing companies. In this case the author investigates household’s interaction with

the systems, efficiency, problems with roof structures and other legal issues related to

the FiTs.

Many people invested in the PV and that is really positive for the environment, but, in

some cases questionnaire respondents felt inadequate advice was provided when

homeowners leased the roof space to third party companies in order to get free panels.

They typically signed contracts for 25 years and that could be a problem when the time

comes to sell the property. In this scenario owners should think to buy the remaining

years of their contract back from the installer (Hajek, 2015).

1.4 Surveyors Concerns

Surveyors advise, with due diligence, that PV panels cannot overload the structure of

the building. At the moment the average age from the installations is around 3 to 4

years, and faults in fairly new PV installations are not very frequent. However, over

time, roofs may get damage from defective brackets, modules installed too close to the

roof edge and the continuous action of loads (roof dead loads + total weight of the

panels fitted to the roof + external forces from wind and snow). The Scottish

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Government (2010) BRE and Waterman Group Report recommended consultation a

charted structural engineer and the preparation of a risk assessment report prior to the

installation of the solar array, especially in areas where roofs are exposed to strong

winds.

Liability is an issue that is not completely clear for homeowners and is addressed in

this work. The author’s survey / questionnaire, from which this current dissertation has

been developed, included a question regarding the liability insurance covering for the

panel system. Households were asked if they were aware of the responsibility to

communicate their home insurer about the installation of the solar panel array.

Homeowners also need to have professional advice regarding the consequences of

renting out their roof space. Marketability of the property may be reduced because

there is a third party running the roof space for a certain amount of years. Potential

buyers of the building may not like the idea of having a PV solar installation or to

continue with an existing contract. Santo (2012)

This study intends to provide answers to most of the issues surveyors might encounter

when assessing properties with PV installations. Other professionals may also use this

work to investigate even further how this technology may evolve and up to what extent

government policies will continue to generate opportunities for the construction and

solar panel industry.

1.5 Main Questions for Hypothesis

The study puts emphasis on the responsibility of building professionals at the time of

assessing properties with PV installations. The rapid growth in the market has also

resulted in numerous properties in which it is possible to see the effects of the lack of

workmanship.

The author’s main questions to inform this dissertation are:

a) Can PV solar panel installations damage the integrity of the roofs coverings?

b) Is the principle of permitted development for PV installations a green light for

unscrupulous installers?

c) Before fitting the PV panels, do installers take account of the real condition of the

roof structure?

d) Is the PV installation insured in all cases?

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The author believes that an important number of PV installations may have been

rushed to completion without a proper analysis of the roof strength and characteristics

of their location. Homeowners did not know all the advantages and disadvantages of

PV at the time of the system purchase. Consequently the study will contest the

following Hypothesis.

1.6 Hypothesis

Are PV systems a hidden source of liability for building professionals?

The author accepts that the systems had an important increment in numbers since the

implementation of the FiTs in 2010. The study challenges the idea that installations

figures are the only consequence of people’s concern for the environment. Our

intention is to bring to light most of the stories from PV users from the last 4 to 5 years.

Those accounts are the first source of information from which the hypothesis might be

tested.

The possibility of failure from the mentioned elements and the lack of workmanship are

considered within the scope of the study. The author aims is based in the idea that

some installations may have problems with the calculations of the loadings, because

many roofs have been completely covered with the solar panels and that will be

opposed to the Approved Document A (AD.A)

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Chapter 2- Research Methodology

2.1 Methodology:

In order to elaborate the appropriate methodology, the researcher analyse the main

subject of the current dissertation:

Photovoltaic Domestic Installations

The choice of methodology will be informed by the following questions:

- Which is the problem?

- Who are the individuals affected?

- What might be the cause of the problem?

- Why the people may be affected?

- How would be possible to solve it?

Own graphic 1: People involved in the Problem

The author agrees with the use of interviews and questionnaires employed in Morris –

Marsham (2010) study. Online surveys are not use in the current work. With the

intention to engage with the public the use of interviews (qualitative method) is planned

in first term with householders, following by building surveyors, installers, council

officials and installers.

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a) Interviews:

The advantage with interviews is that they can provide a closer view from a problem,

which in words of Lapan, et al (2011) ‘These qualitative studies focus on giving voice to

those who live experiences no one else could know about directly’. In addition, and

following the intention from the author of the current dissertation to participate actively

in the collection of the data, it would be important to cite: Shensul (2011), chapter 4, In

Lapan, et al. ed. ‘Some Qualitative researches choose to involve themselves in the

field or the study setting and participate in it’.

Kirk and Miller (1986) note that: ‘the most critically, qualitative research involves

sustained interaction with the people being studied’ which promotes use of interviews.

It is also true that artificiality is a criticism of formal, structured interviews (Hammersley,

1992) – thus, informal interviews were preferred in a natural (ethnographic) setting for

the householder interview

In the event, 12 homeowners and 4 different professionals from the construction

industry accepted interviews to enrich the study results. The Interviews were designed

according to the categorization given by Naoum (2013), he provide three types of

interviews.

The authors have used unstructured interviews, in which the questions are open, and

Semi-structured interviews as the questions did not followed a particular order. The

interview questions in this case were thus guide words to support an open discussion

on the topic. Interviews were pre-arranged.

b) Questionnaires:

Another method used to gather information it was the construction of questionnaires,

they respond to a quantitative method to gather information.

Naoum (2013) states: “Quantitative research is ‘objective’ in nature. It is

defined as an inquiry into a social or human problem, based on testing a

hypothesis or a theory composed of variables, measured with numbers and

analysed with statistical procedures”(p.39)

All questionnaires were completed by homeowners who incorporated the technology.

The chosen approach was to send questionnaires to 84 households, whereas the

actual quantity was 74 since people were on holiday or away. The questionnaire

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technique was selected to provide a uniform response, allowing the objectives to be

evaluated in a consistent way.

The aim of the household questionnaires was to obtain most of people experiences,

motivations for acquiring and fitting solar systems even that returns for the investment

were not very rewarding for some households (late installations). Their involvement

with the systems is a vital element for building surveyors as they can provide the check

list of elements that can fail or malfunction. Even those systems are fairly new, there

are already signs of problems and our purpose was to collect and analyse them.

All the information was gathered in order to find answers to the hypothesis. The non-

intrusive inspections of the areas were planned in advance. The author was looking for

evidence of the systems installed and the condition of the units. The opinions and

perceptions from all participants are expressed within the analysis of the data.

C) Non- intrusive surveys:

The observations were done from a distance, to avoid disturbing the owner’s privacy.

-The research employed the following methods:

1.) Household questionnaires

2.) Household interviews (unstructured)

3.) Surveyors and like professionals interviews (semi-structured)

4.) Non-intrusive surveys of properties visited

2.2 Questionnaires:

The author preferred the printed option as the model to follow. Hard copies included

21 questions from diverse aspects of the panels systems. They were organized to be

completed in 10 to 15 minutes.

The study took place within 3 neighbourhoods in the city of Sheffield. The author

selected the properties using satellite views from Bing maps and Google earth.

Participants received the information from the scope and objectives from our research.

As some of the participants preferred to be anonymised, they were allowed not to

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include their names in the form. Distribution of questionnaires took place between 25th

of June and 17th of July of 2015.

List of subjects included in the questionnaires for householders:

Ownership of the panels

The type of units installed

Influences for their choice

Issues related to the roof structure: reinforcement of trusses, rafters, plates,

joints, etc.

Improvements done in the premises prior to installing the panels: new loft

insulation, cavity wall insulation, double glazing, new boiler, etc.

Quality from the roof inspection by PV installers

Type of insurance covering the PV system

Leasing the roof space to a third party

Sale of the property

2.3 Questionnaires Distribution Map:

Fig 1: Digimap.edina.ac.uk/roam/os, 2015……..8

Base in the idea of: The Impact of Solar Panels on the Price and Saleability of Domestic Properties in

Oxford, Final Report, Morris-Marsham, 2010, UCL, p.18

Table 1: Type of installations

PVtp Installation

PVsp Installation

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Information:

The distribution area for the questionnaires took place within the purple boundary

(extended map). This area includes S17 (Dore, Totley & Bradway), S7 and S8.

Within S17 (red boundary), 29 households completed the questionnaires. Among S7

and S8, only 6 householders completed the questionnaires. The final count for the

sample was 35. The total of delivered questionnaires was 74 and the rate of completed

reached 48%.

The chosen area (S17) has the advantage of having a small number of households

compared with others in Sheffield. According to (Postcode Area 2015) there are 15,483

residents divided into 6,885 households.

Table 2: Rates responses

Chart 1: Number of Questionnaires Delivered

Dore area alone

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2.4 Interviews:

Interviews were designed to investigate what stakeholders think about the PV systems,

particularising the benefits and the drawbacks. With the purpose to enhance the scope

of the current study, the author considered indispensable to appreciate the issue from

different perspectives.

Householders were invited first to have interviews as a part of the study. For reasons of

time only 12 people accept the invitations. Results are presented in section 4.2.

Building surveyors were called to take part in the research. Unfortunately, many of

them declined because the subject was outside their expertise (see list of surveyors in

appendix 9.6).

The author deliberately planned to incorporate in this work the input from different

stakeholders from the construction market, with the purpose of assessing where points

of agreement, as well as discrepancies, could provide answers for the hypothesis.

People invited to take part were:

Householders…………………..

State agency valuer: ………….

Solar panel installer……………

This additional data provides an insight into the supply chain and complexity of the PV

market, and the prospects for the coming years.

2 Own Diagram

Building surveyor…………….

Council officials………………

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2.5 Interviews to Homeowners Map:

Fig. 2: Interview to Homeowners. (Mapping Idea from: Morris-Marsham Report p.18)

Digimap.edina.ac.uk/roam/os, 2015

Interviews to

Homeowners

Chart 2: Total Interviews among S17, S7 and S8

Table 2 a

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2.6 Outlines from Chapter

The volume of solar panel installations have escalated rapidly in recent years; from 2.7

GW installed capacity in 2013 to nearly 4.7 GW in June 2014 for the UK (Vidal 2014).

The figures are auspicious, but, the purpose of the current dissertation is to determine

if this augmentation in the number of PV units fitted has also been accompanied with

the correct evaluation of the roofs loading capacities.

The methodology chosen by the author relies in the neighbours’ wish to participate and

describe their experiences with the technology. No previous studies from the number of

installations were found. The only advantage is that the author lives in the area and

people may contribute with the sample.

2.7 Limitations

The selected area for the study (except 6 houses) has the advantage of the relatively

small number of households (6885) ( Postcode Area 2015). The post code comprises

the areas of Dore, Bradway and Totley.

There is a marked social and economic difference between the upper areas of Dore

with the rest of the neighbourhoods. The surplus of income in the area facilitates

households to invest in PV systems. The average price for a 3 bed house in Dore is

£356.565. In comparison, the same number of beds in Bradway is £256.763.

(Rightmove 2015)

Due to the topography of S17, many houses have solar panels opposite to the street

side. This makes it difficult to assess them, and so the author extended the search

towards S7 and S8. People received questionnaires in person in order to maximise an

ethnographic approach, and they were offered an interviewee at the time of

questionnaire collection. Some houses were visited 2 or 3 times in order to find the

owners.

The author found that the households who rent out the roof space to a third party did

not obtain all the information regarding the issues of liability involved in the deal,

especially in regard to the sale of the property when having this type of contract. They

were content with the idea of getting free energy.

Interviews with building professionals were carried out within the time frame provided

by them. The author accepts the fact that the respondents and interviewees who

participated in this study had the chance to express with freedom their own particular

opinions.

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Chapter 3- Literature Review

3.1 Aims of the Chapter

The following section analyse the literature regarding Photovoltaics Systems

establishing its origins, the legislation that made it possible and the last development;

articles, conferences, studies and all other literature referred to this technology. The

author critically presents the sources establishing its parallels and contradictions with

the current reality.

3.2 History

Photovoltaic Technology has been around for almost 160 years’. From Alexander

Becquerel (1839) who first observed the phenomenon of transforming light into

electricity, to Albert Einstein producing his Nobel Prize writing in regard the subject in

1905: “On a Heuristic Viewpoint Concerning the Production and Transformation of

Light”, the technology has been evolving up to the present form. (Sunlight Electric

(2015)

The year 2000 marked the beginning of the FiTs in Europe; Germany promoted the PV

industry creating subsidies with the aim to expand the number of installations Morris

(2015). Following this trend, the UK has also delivered active policies, creating tax

incentives and relaxing building regulations in order to speed up private investment.

3.3 List of Sources

3.3.1 Energy Act 2008, HM Government

This legislation came into force in November 2008. It was the government response to

the threat of the climate change (mentioned in the Stern Report (2006) “The Economic

of the Climate Change”) and the increasing dependency from England to energy

imports The Act regulates and improves the licences for the supply of off- shore oil and

gas creating at the same time the structure for the decommissioning and clean-up of

old energy plants.

14

Legislation precedents: we can find the background for this Bill in the EEG (German

Energy Act); British Electricity Act 1989, Energy Review of 2006 and the Energy White

Paper from 2007.

Remarks:

The EA2008 is a piece of legislation that tries to simplify all the previous attempts to

rule an always evolving subject – the energy. This Act shows the government

intentions to diversify the sources of energy. It is important to mention that the

Secretary of State: ‘has the power to make the arrangements for the administration of

diverse stimulus for Low Carbon Technologies’, (Energy Act, 2008: Sec 41, Chapter 4,

part 2).

Section 41 (5) of the Energy Act (2008) defines 9 sources of energy, in particular:

photovoltaics (d) and solar power (g).

Limitations:

FiTs were implemented in 2010. It took 2 years since the publication from the EA2008

to become available for the households Hull (2015). People who installed solar

systems prior to the implementation of the scheme have a different treatment than the

people who fitted the systems after 2010. Since 2011 the scheme had suffered

successive reductions in the amounts paid to homeowners for the energy produced

(RECC 2015)

3.3.2 Retrofitting Solar Panels, LABC Guide (2011)

This is a practice guide for the installation of PV panel systems published by the

authority of Building Control in England and Wales in 2011. The guide places emphasis

on the need for Solar Panels to comply with the requirements of the Building Regs,

AD.A Sec. 4 (Roof Coverings). Clause 4.4 of AD.A (2010) takes into account the

‘significant change in roof loading’¹ when the load applied to the roof structure is

increased in excess of the 15%’.

Remarks:

This note states that assessments for roof structures need to be done by a certified

member of the CPS 2009 (Competent Person Scheme) with qualifications obtained in

the City Gilds 2372-Photovoltaic. CPS is a self-certification scheme introduced by the

government in 2002, Planning Portal (2015)

15

The note highlights how the PV loads may affect the structure of the roof, with the

installer responsible for its integrity. The author calculated that the average weight of

the roof can be incremented around 19.8kg / m² (for a rafter with an average weight of

132 kg/m²) (ILO, 1992). The weight of a solar panel is around 20kg/m.

In addition, this note asserts that will be necessary to determine the strength and the

quality from the roof connections which is the ‘clamp bracket screwed to the rafter’. In

exposed areas recommends to work with a ‘Dynamic Pressure of q = 1.2 kN/m²’³ for

England and Wales.

The work advises to differentiate between modern trussed rafters design from the

traditional cut roofs. Modern roofs with standard structure (fink trusses) may allow an

extra load, however, an investigation needs to be carried out in order to assess the

condition of the timber, metal joints (gussets) and plates. The guide declares that Pre-

Victorian roofs may be better prepared to support the modules, as they were

constructed with better quality woods.

The LABC guide (2011) recommends to be cautious with the constructions from the

first half of the 20th century as well as and bungalows from the 1960’s and ‘70’s. It

concludes by saying that the roof could be working at the maximum of its strength.

Limitations: The author agreed with most of the statements from the LABC notes, but,

there is no reference to what is happening at the moment. More strict calculations of

roof loads could be carried out.

3.3.3 Parrett, Stuart, (2012)

This is an article published by RICS in 2012 Stuart (2012) provides an overview from

the surveyor’s new role of assessing installed PV systems and the problems originated

for exceeding his competencies.

Remarks:

It makes reference to the HBRs in which the surveyor inspects properties with solar

panel arrays. It suggests setting up some limitations in the advice given to clients who

wish to retrofit their roof with the mentioned elements. According to the article the

surveyor’s inspection is only referred to the suitability of the roof to incorporate the

panels, which does not extend to calculations.

16

Limitations:

Apart from the advice in the condition from the roof components the author considered

that the surveyor should also provide information regarding the advantages and

disadvantages from the solar systems. People have rushed to purchase the mentioned

technology, and on some occasions they have been induced to buy something that is

environmentally friendly but arguably from the cost-effective point of view.

3.3.4 Parnham, Phil (2012a)

In this article published By RICS, Parnham (2012) analyses most of the issues referred

to PV installations when the FiTs started to boost the number of installations. He

mentioned how the reduction in payments from the scheme made by the DECC

demonstrate that the policy was too good to be truth. During that year the generation

payment for a domestic system with 2.7 kWp was around £990. In 2015 the figure is

around 50% of that.

Remarks:

He analyses the problem originated from free offer of solar panels to households by

which the homeowner allows a 3rd party to lease his roof space for a period of 25 years.

This fact brings serious legal implications at the time to determine who is liable if the

panel causes damage to other people.

Homeowners need to know that they must buy the solar panel array from the company

who owns it in order to have freedom of movement.

Parnham (2012a) asserts that in some cases the company who owns the panel will

allow the new owner to purchase the panels at a cost less depreciation.

Parnham finally declares that: “the myth of free electricity is intrinsically related the

occupancy of the premises”

Comment:

The author agreed with this article in the majority of the points as it was one of the

clearest analyses of the market in 2012. The topic of the article is expanded upon in

Parnham (2012b) the book: “Assessing Residential Building Services” published by

RICS and written by the author of the article, Phil Parnham. where it is clear that the

problems with the FiTs are still affecting the solar panel market.

17

3.3.5 Santo, Philip (2012)

Santo (2012) enumerates the downside from the PV Systems. Santo (2012) starts by

describing the rush from homeowners for securing a lucrative investment in the green

technologies.

Remarks:

Santo (2012) emphatically declares that many things can go wrong. Firstly because on

many occasions there is no consideration for the location of the property; in addition,

when the orientation of the unit is not completely south facing, the efficiency of the

system can be seriously affected. The other argument that he presented is the difficulty

to mortgage a property when the owner has installed the panels for free. The new

owner may not be considering taking the responsibility of the lease left by the previous

owner.

Aesthetics is another issue covered by Santo (2012), since some people do not like the

idea of the panels altering the appearance of the house.

Santo (2012) makes reference to the MCS certification as being the only way to be

entitled to have the highest rate of the FiTs.

Santo (2012) mentions the Council of Mortgage Lenders. The lender may constrain the

homeowner who has a FiT on his property to remove the installation if it affects the

saleability of the house.

Limitations:

We agreed that in 2011 it was too early to make a prediction about how the FiTs were

going to be accepted by lenders. Now 4 years since the implementation we can still

find similar difficulties at the time of selling a property with a leased roof. The

recommendation for the homeowner is to buy the remaining years of the lease from the

solar company who install them in order to facilitate the sale.

3.3.6 The Impact of Solar Panels on the Price and Saleability of Domestic Properties in

Oxford, Final Report, Morris-Marsham (2010)

The research/study in question was presented in 2010 as a final dissertation for a

Master degree in Environmental Design and Engineering at UCL. The results of this

study are based in surveys and directed questionnaires delivered to residents in

Oxford.

18

Remarks:

Morris-Marsham (2010) examines the impact of the solar technology in the price of the

houses in which they are incorporated. Using questionnaires and surveys they explore

the probability that PV may increase the value of properties due to the reduction in the

electrical consumption. The researcher asks the respondents in one of the questions if

they are willing to pay more for a property with PVtp. Other examples of questions

scrutinises how the aesthetics from the devices may affect the customer’s decision.

Finding connections with the current dissertation the author analyses question No. 7

from the Morris-Marsham study (2010): ‘What is the main reason you would more likely

to buy a property with solar electricity panels?’ (ibid, p.30). Morris-Marsham (2010)

provides 4 possible answers, 2 of which are relevant to this study as further detailed

below.

The most important two are: because it will: b- ‘Reduce energy bills’ and because it will:

c- ‘Reduce environmental impact’.

The response shows that 60% of people answered that the main reason is that they

may reduce the electricity bill, whilst 30% of people responded that they may reduce

the environmental impact from the building.

As the title describes, the study was concentrated in the economic aspect of the PV

systems. The author finds convenient the mapping layout for Questionnaires and

Interviews from Morris Marsham (2010). We adopt and acknowledge this method.

Digimap is used to visualize areas for the sample.

Conclusion:

There is no demand market for houses with PV. The existence of a PV system on the

roof does not influence the final price of the house,

Limitations:

680 questionnaires and surveys were distributed and 30 were returned completed. The

overall rate of response was 4.41%. (p. 18). She delivered 330 web questionnaires with

a very low rate of returns (only 5); she delivered 350 hard copies, with 25 returns. The

study was done in 2010 when solar systems were just starting to be part of the

townscape.

19

3.3.7 Ridal et al (2010)

This was a research study focussed on the structural impact of PVtp and PVsp in

domestic and non-domestic buildings commissioned by the Building Standard Division

of the Built Environment Directorate in Scotland. The systems were applied to different

kind of roofs assessing the effects of the loads on ‘trusses and connections’ (p. 4)

Remarks:

The importance of the study in question is the effect that extra loadings applied to roof

and walls could cause to the structure of buildings. The number of systems installed

assessed by this research was 4: PVsp fitted to slate tiles; PVtp incorporated to a metal

frame (evacuated tube type); PVtp fitted to roof tiles (flat plate collector) and a PVtp

fixed to an internal wall inside the property.

Firstly Ridal et al. (2010) describes in detail the systems components making the

difference between the PVtp ‘solar water collectors’ (ibid, p.8) and the usual PVsp ‘tile

type solar collector’ (ibid, p.9).

The study considered all the requirements for constructors taking on board PV solar

installations which are clearly stated by the MIS 3001(2009). (Solar heating

microgeneration standards), Published by the DECC in 2009 (Requirements for solar

PV standard

Support for solar systems (brackets, fixing and metal frames must comply with steel or

galvanized coating to protect the installation for at least 20 years for the first service, in

accordance with ‘BS EN 10088 and BS EN ISO 14713’ (Ridal et al 2010).

Basically the PVtp contain fluids and can have different shapes and sizes:

Fig. 3: Sky Flair Ltd (2015) Evacuated tube collector:

20

Fig. 4: The Green Home (2015) Flat plate collector:

Within the analysed study the writer itemises each component of the roof in order to

calculate dead loads and forces acting on the trusses.

Weights from solar thermal panels (PVtp):

The average unit form evacuated tubes collectors (Fig 3) have a weight of 50.3 kg up

to 76 kg. The solar plate water collectors (Fig 4) have a weight from 25 Kg up to 44, 4

Kg (empty). These kinds of panels are heavy and the roof needs to be strong enough

to support them; consequently trusses should be checked.

Information for metal frames and PVtp:

Metal frames have a weight of 17 to 22 kg (ibid, p. 13).

Filled PVtp (solar thermal) attached on-roof figures are:

Type A (flat plate PVtp) = 0.19kN/m² Type D (flat plate PVtp) = 0.20kN/m²

Type E (evacuated tube PVtp) = 0.22kN/m²

A water tank of 300 litres to store the water produced by the solar thermal panel can

exert a force = 0.98 kN/m² (important when fitted within the loft space)

Example of load for PVsp (solar panels): The solar panels (PVsp) tile type, used for the

study had a weight of 14 kg/m² and 19.7kg/m². (Ridal et al. 2010).

21

PVsp diagram with components:

Fig. 5: Combined images from: P 3.4.7.c: Dow Corning (2015) & P 3.4.7.d: Pearl Solar Panels

(2015)

According with the figures, rafters (trusses type) can support an average of 0.78 kN/

m². Concrete tiles can exert a load = 0.65 kN/m², which mean that the roof will have

some margin of capacity to incorporate a small load (0.13kN/m²) (p.22),

Findings:

The study showed that tests with solar panels Type G and H applied to the roof

produce stress in the components of the truss but ‘within acceptable limits’ (ibid, p. 23).

The authors observed that those loads could cause the roof to be in excess of the 15%

and it is considered as a ‘significant change in the roof loadings’. (Building Regs, AD.A

2010, clause 4.4, p 40)

Wind loads have been calculated with a speed of 24m/s, (BRE Digest 489 (2004). p.3)

22

Fig.6: BRE Digest (2004 p.3)

An important finding from this study is the impact of the wind when applied to the roof

surfaces. Looking at the figures from the graphic extracted from BRE (2004:p.24) is

possible to visualize that negative forces (up-lift) are stronger than the positive forces

acting on the surface of the panels (downwards).

Table 3: Ridal et al (2010) BRE & Waterman Group, p. 24

From Table 3 it is possible to establish that up-lift forces have a substantial impact in

the final loading on the roof. The figures evaluated correspond to the PVsp

(Photovoltaic Solar Panels, On-Roof type)

23

The mentioned unit is mounted on a metal frame system which is attached through the

tiles to the rafters of the roof; this situation allows the wind to circulate between the

surface of the tile and the solar unit. Up-lift forces will be greater than the ones acting

on the surface of the panels.

Relative advantages from Fink Trusses (standard configuration):

Standard modern trusses in England should comply with: (BS EN 14250: 2010) ‘Timber

structures. Product requirements for prefabricated structural members assembled with

punched metal plate fasteners’. The trusses thickness should be no less than 35 mm.

The roof design and the number of trusses will determine the strength of the final roof.

Finally, the study asserts, that trusses with standard configuration, covered with

concrete tiles and PV panels (on-roof type), may work at their limits of loading capacity.

Fig.7: Cortez Colorado (2015) Fink-truss Image [online]

Fig 8: Truss Corp (2015) Prefabricated Roof Truss [online]

24

Other Roof Configurations:

Roofs structures which are not fink trusses require even more care, due to the need of

calculation from individual members, which have been made on-site like a cut-off roofs

for example.

In-plane roof solar thermal and In-roof solar panels are better to fit because the

coverings of the roof (tiles, slates, etc.) are taken off and replaced directly with the

panels (see Fig. 10). In this case, dead loads and wind effect is reduced, preserving

the integrity of the roof.

Limitations:

There was an error on page 35; the study announces the analysis of 6 case studies,

but provides the results for only four. The author did not take results from the solar

thermal unit attached to the wall, since this present study did not encounter any sample

with the same characteristic within the analysed area in Sheffield. Ridal et al (2010)

report has a reduced number of cases and cannot represent the installations of an area

of Scotland.

3.3.8 Guide to the Installation of Photovoltaic Systems, MCS (2012)

This is the main source of information for Solar panel installers. Published by the

Microgeneration Certification Scheme in 2012, it came into force in 2013. It is a

technical guide in which all the requirements for the installers are considered.

(MCS Guide 2012) starts by defining the scope and the purpose of the guide and

immediately goes to the design section to analyse the type of module, electrical,

cables, fuses, insulation, etc.

After that, the issue of the performance is discussed; in this case there is a change due

to incorporation of a database from Europe called PVGIS, which measures the

irradiance.

The (MCS Guide 2012) also provides information about the appropriate inclination of

the panels, shading and orientation according to location. Load calculation, mounting

and fitting are explained in detail. Margins for the panels should be 40 to 50 cm (ibid, p.

74).

25

Remarks:

Inconsistencies in relation to European codes are stated in section 4.3.7 from this

guide:

…’roof systems for pitched roofs suggest a screw layout that conflicts with the

requirements of [BS EN 1991-1-5] Eurocode 5 to keep fixings a certain number

of screw diameters away from the rafter edge and each other. In such cases

one solution is to fix the mounting bracket to a timber noggin fitted between the

rafters. Alternatively, the fixing resilience can be determined from test data’.

(MCS Guide, p. 71)

Downsides:

The author sees this issue as an important weakness in the British legislation. The

suggestion of a noggin addition to the rafters in order to attach the anchor (MCS guide

p. 71) is a tacit indicator of agreement that the rafters are not thick enough. It leaves

the issue to be solved by the installers; please refer to appendix for the interview with a

solar installer (see appendix 9.4).

3.3.9 Solar Panels Mounted on Building, Norfolk County, Canada

The Ontario Building Code (2013) has very stringent legislation, since it is required to

have a building permit for any solar installation in which the array has more than 5 m²

of surface.

Remarks:

In Ontario, any application must come accompanied with plans from the project

describing all the specifications from the proposal. It is required to have a signature

from a Chartered civil engineer. The homeowner must present 2 set of drawings. The

submission is checked by the council and assessed on site by an inspector. Electrical

connections are also subject to inspection from the electrical board.

In addition, it is necessary to present with the form, all the details from the equipment

as well as the structure of the roof, loading, and members affected by the installation.

The author agrees with this legislation - whilst it is very conservative, it reduces the

liability for installers and homeowners.

26

3.3.10 Assessing Residential Building Services, Phil Parnham (2012)

Parnham (2012b) outlines the surveyors’ approach to building services. The complexity

in construction brought by the incorporation of new technologies can make surveyors

feel overwhelmed. Regarding solar systems Parnham (2012b) recommends to be

cautious at the time to assess properties in which the client has installed PV panels or

is thinking on doing so.

Remarks:

Parnham (2012b) places highest risk on electricity supply because it is a dangerous

service and can cause death. He recommends an exhaustive assessment and

highlights how often illegal connections can be found inside the premises.

Surveyors are advised to ask the homeowner if the installation has been undertaken by

a company with a MCS accreditation; this would allow the work to be registered in the

Feed in Tariff Scheme (FiTs). Electrical connections need to satisfy the requirement of

the Building regulation Part P and the person assessing the roof structure with Part A.

(ibid, p.24).

Parnham (2012b) provides clear guidance for surveyors assessing properties with solar

PV panels; from the outside; condition of the panel, orientation, shading and roof

coverings. From the inside: the roof structure, evidence of sagging, and the working

condition of the electrical system. Parnham (2012b), p.24

Additional loadings need to follow the limits stated in the Build. Regs. AD. A, Sec. 4,

4.4 (analysed on page 21).

Limitations:

It was published in 2012 when the technology started to be known. Precedent of the

FiTs was scarce at that time and the legal consequences of leasing the roof was not

predicted.

3.3.11 UK Solar PV Strategy Part One: Roadmap for a Brighter Future, DECC (2013)

Remarks:

Published by the DECC (2013) this sets out the needs from the UK to diversify the

sources of energy. The target is to reach the 15% of the energy from renewables by

2020. The British Government will promote PV installation with others sources of

energies, aiming to reduce the impact from carbon emissions. Local communities will

27

have the benefit of taking part in their own decisions. DECC (2013) makes reference to

Part 2 that was planned to be published the following year.

3.3.12 UK Solar PV Strategy Part Two: Delivering a Brighter Future, DECC (2014)

Remarks:

Published in 2014 the policy goes further with the government intentions to support the

PV industry expansion. It mentions the necessity to continuing supporting the small

scale production of energy (domestic), but the mid-size sector (industry and

commercial scale) is foreseen as the next step to develop. The DECC (2014) highlight

that the rapid process of growth in large-scale solar farms could jeopardize the funding

for the rest of the sector. DECC (2014) puts accent in the wealth and employment

brought from the PV industry and plans to promote exports from the British technology

in PV systems.

Drawbacks:

There are things to revise within the Policies. The abrupt reduction in the payment of

the FITs to small energy generators might discourage homeowners to purchase the

systems; there will be no incentive to acquire them in the short term. It does not show

that stakeholders have been consulted prior to elaborating this policy.

3.3.13 Screw pull-out tests on wooden rafters with a rafter width of 35 mm, Zapfe

Zapfe (2011) measured the resistance from screws to pull up forces. The study uses

wood with 35mm of thickness, similar to the rafters commonly used in England as

standard. The importance of this study is that pull out forces are usually exerted when

the solar panels are mounted on roof and the wind is allowed to circulate freely under

the panel module.

Remarks:

For the experiment screws from different diameters and lengths were used. Screws

have been incorporated into the wood under different situations, screwing them directly

or pre-drilling a hole into the wood with a smaller drill bit before screwing them in.

The test pulls out the screws by pairs and done using a hydraulic machine. Results

showed that the screws did not display deformation but they damaged part of the rafter.

When the screws were introduced near the edges, the opposition to up lift forces

28

reduced drastically. The study emphasizes that rafters with this thickness do not

comply with the Normative of Eurocode 5 DIN EN 1995.

Diagram 3: Own Diagram obtained from the Zapfe study

Figure 3: was made from the written information included Zapfe (2011). It shows the

thickness for the rafters according to DIN 1995 Eurocode 5 and the usual width for the

UK. Up-lift forces may cause more damage to trusses 35mm width, as they will have

screws closer to the rafter edge if the installer uses imported anchors. For screws

minimum sizes and pre- drilling guidance can be found at: EN 1995.1.1.2004 Eurocode

5 (2004). Minimum truss thickness for England is defined by BS EN 14250 (2010) p.9

5.4.1.

Limitations:

The study was made using individual members with 35 mm. It was not tested under the

real action of wind forces, acting against the whole structure of a standard tiled roof.

29

3.3.14 Blowing in the Wind? VIRIDIANSOLAR

Viridian Solar (2014) emphasizes the importance of the wind load within the design of

the roof system. The paper states that areas can be more exposed to wind than

others, all depending to the topography, location, altitude and distance from the sea. It

also makes differentiations according to the modules design.

Remarks:

Pressure coefficient values correspond to BRE Digest 489 (2004 p.3) Viridiansolar

(2014) recommends working with timber with a higher safety factor (1.44) and advice is

provided for installers to assess the product according to the location in which it will

perform.

Screw resistance should be: ‘equal or greater than to 12 times the diameter of the

screw’ (ibid, p.3). This explanation means that for a screw of 3 mm diameter, there

must be a rafter of 36 mm of thickness. For in-roof solar modules states, that in most

cases if the product has been designed for other European countries will require

battens 35mm by 35 mm thick. The most popular battens use in the market in England

have 25mm (Affordable timber Battens 2015); this is a common mistake when installing

this type of products (ibid, p, 3).

Fig 9:

VIRIDIANSOLAR (2014) Blowing in the Wind? In-roof PV panel examples

Limitations:

They try to promote the benefits from their own products in the guide and do not show

figures from other designs available.

30

3.3.15 What is a kWp? Evoenergy

KWp: Kilowatt Peak, A kind of test for Solar PV panels in order to measure the module

performance. ‘Is the irradiance of 1000w/ m², with a module temp at 250º C, and a

solar spectrum of 1, 5’.

3.4 Chapter conclusion

The analysis of the literature shows that the technology has benefited from the

government decision to subsidy PV installations. This is a valid reason from an

environmental point of view. The current dissertation describes the existence of some

discrepancies between English and European codes in regard to rafters supporting

solar modules. Householders did not take account of the problems that the system can

cause when loading is at the limit of its capacity (>15% of roof extra weight). Anchoring

of the modules can be unstable if the unit has not been properly secured to rafters or

battens; screws need to be pre-drilled and far from rafter edges.

A rapid increase of installations has been motivated due to financial rather than

environmental reasons. People did not have the right information at the time to

purchase. They were enticed with the idea of free or cheap energy. The prospect for

the industry is not clear as the government wants to reduce or eliminate subsidies for

small electricity producers under the FiTs. (Macalister 2015)

Surveyors will have an important role in the appraisal of properties with solar PV

systems. Loads, workmanship and liability will be the main factors in the assessment.

Other stakeholders will need to work together in order to find a new framework for the

market. Councils should take a more active role in the control of solar panel

installations in premises where the surface covered with PV panels takes a large

amount of the roof. Therefore, our legislation will have to change accordingly,

particularly since there is a need to comply with European codes for timber

construction.

31

Chapter 4. Survey and Findings

The following tables and charts have been designed with the results obtained from the

questionnaires distributed to households between 25th of June to the 17th of July of

2015. The sample correspond to the post codes: S17, S7 and S8 in Sheffield (see Fig.

1).

A total of 73 hard copies were distributed to householders. Thirty-five self-completed

questionnaires were collected back, reaching a response rate of 47.94%. The original

respondent sample size was 84, and the author fulfilled the 42% of that target. The

numbers of questions included in the copies were 21.

Questionnaire provided in Appendix 11.1.

4.1 Answers to Questionnaires:

4.1.1 Q.1

This question refers to the existence of a solar panel array in the premises, a working

unit, producing either electricity (PVsp) or hot water (PVtp)

Chart 3: Existence of a working solar array

Question 1: “Does the occupier have a solar panel array?” (A working unit)

Within the yes group the authors include all type of solar panel system.

32

Remarks: From householder’s accounts the panel systems seems to be working

according to installer’s predictions, except in one case where the property was

purchased with the installation in place. The oldest system was fitted in 2007.

4.1.2 Q.2

The following question explores the probability that the PV system was already

installed by the previous owner or by the developer. Is possible to see new

developments where the buildings need to produce at least 10% from its energy from

renewables. From the visits to properties at the time of the questionnaires distribution,

only in one occasion the house was purchased with the panels already installed.

Nevertheless, it had solar thermal collectors.

Chart 4: Installing the solar array or buying it with the property

Question 2: “Did the occupier install the PV panels or were the panels already in

place?”

Remarks: The numbers of responses confirming that homeowners installed the panels

were 34 (97.14%), Only one property situated in the area of Totley (S17) was

purchased with an existing solar thermal unit. This makes the 2.86% (rounding 3%)

from the total,

33

4.1.3 Q.3

Question 3 makes reference to the type of solar system that the homeowner has

decided to fit in his property. Ideally, if well advised, choice will be related with the

occupancy of the premises.

Solar PVsp?

Solar PVtp?

This question is linked with question 4 (factors that influenced the occupier’s choice).

Solar energy at the moment cannot be stored (until cheap batteries are available). It

means that if during daylight hours the property is empty and the consumption is low,

all energy produced by the system will go to the grid, producing a very small return.

Fig 11: Solar Panel Unit, (Own Image)

Fig 12: Solar Thermal Collector (Own Image)

34

Chart 5: Type of system

Question 3: “Is this a Solar Panel System, Solar Thermal or Both?”

Remarks: From 35 responses, the vast majority of houses (28 premises) have

installed PVsp, mainly due for the advantage of FiTs generation payments. These are

the 80% of households in the survey. 4 houses have installed both systems (PVsp &

PVtp) at 12%, and finally 3 properties have only fitted PVtp (9%).

It is obvious that return and investment are important factors in the homeowner views.

Please see Q.4 Op (D) for other consideration involved in the choice.

35

4.1.4.0 Q.4

The question underlines the factors that have influenced the occupier’s choice.

Question 4: “How far did the following factors influence the occupier’s choice?”

Three choices are given to householders. Each factor has a level of agreement, from

none to fully.

Remarks: In first term (A) is the production of electricity and the possibility to use it as

is produced. After that (B), is the chance to sell the excess of energy to the grid and

finally (C), is the environmental motivations for the investment,

Option (D) accounts other considerations; the author left a blank space to be filled with

the testimony of the participants and they have created all the options.

Table 4: Figures from the responses A; B and C:

36

Table 5: Option D: People created the options from what they considered important,

these are the figures:

4.1.4.1 Q.4, Option (A) from question 4

Chart 6: Use energy as is produced

Question 4, (A): “Households / occupants are able to use the electricity as it is

produced during the day”

Within the chart all PVtp (solar thermal) and PVsp (solar panels) are counted.

37

Remarks: three people answered “None” (in blue) is because they have PVtp and their

systems do not produce electricity as such. Their systems heat up water instead.

The rest of the people have PVsp or a combination of both systems. They are able to

use the energy directly as is generated. From the combination of households Green

and Purple (65.71 % of people), is possible to see that owners with solar panels units

can use a decent amount of the energy during daylight hours.

4.1.4.2 Q.4, Option (B) from question 4

Chart 7: Able to use electricity

Question 4, (B): “Being able to sell unused electricity to the national grid”

Remarks: In this chart we have the opposite situation than in the previous chart. As the

energy is not consumed in the premises, is exported to the grid at a very low rate 5.94

p/kWh. (See Appendix, RECC (2015) Consumer Feed in Tariff). The chart shows that

people are able to export energy to the grid (Green and Purple accounts 71.43 % of

households). If the amount of energy exported to the grid is higher than the used in the

premises, is evident that the system is not a good investment, unless they have the

highest rate for FiTs generation tariff (units installed before 2012).

38

4.1.4.3 Q.4, Option (C) from question 4

Chart 8: environmentally friendly

Question 4, (C): “Being environmentally friendly is a good long term investment”

The chart shows a high percentage of commitment to the environment. The answer “a

little” indicates an economic interest in the system only, leaving behind the green

agenda. People answering a little have joined the FiTs. Combining the biggest groups

(Blue and Green), they account together 88.57 %

39

4.1.4.4 Q.4, Option (D) from question 4

Chart 9: Other considerations

Question 4, (D): “Any Other consideration involved in your choice?”

Remarks: The graphic was created with the quotes left by the participants of the

survey. They account more than 50% of the final sample. This is a subjective view from

the motivations to install the PV systems. In only one case the respondent is not

mentioning the economical side of having them and, instead, prioritizes the need of

clean electricity. This example accounts the 5.5% from the 18 respondents to Q. 4

Option D.

There is a general idea that FiTs is Not Taxable, but, if the owner of the house has a

registered business in the premises he/she will need to ask his accountant. Idem for

landowners who rent the premises and have an income from the house.

40

4.1.5 Q.5

Question 5 inquires about how the homeowner believes he / she were advised at the

time of purchasing the system. The selection of the type of system is crucial. The solar

company should tell the homeowner the benefits of having a PVsp or a PVtp system, in

order to maximise the energy use that he / she will be able to generate.

Chart 10: Advice at the time to purchase

Question 5: “Does the occupier believe that he / she received a good advice when

they purchased the system?”

Remarks: this question makes clear reference to the quality and fairness of the advice

given by the solar installer company, which in theory should assess the needs of the

households according with the occupancy, energy consumption and life style of the

customer. A high proportion (88.57%) of the sample said “Yes”.

41

4.1.6 Q.6

The question makes reference to the necessity of improving the energy efficiency of

the house, in order to be eligible for the FiTs, the house should have an EPC = Band D

or higher. The numbers of the properties that have made improvement to comply were

23 dwellings.

Chart 11: Improvements

Question 6: “In order to improve the energy efficiency of the property; did the occupier

make any other improvement to the house before the Installation took place?”

Remarks: the number of houses with improvements was 23 from a total number of

improvements of 34. This means some properties made more than one refurbishment

in order to be more energy efficient. The cost of the installation in these cases was far

more expensive.

Table 6: Improvements

PART 1

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4.1.7 Q.7

This question is related to the quality of the inspection made by the CPS administrator

or any other professional who made the assessment of the structure of the roof and loft

before fitting the solar array.

Table 7: Roof assessment

Chart 12 Satisfaction

Question7: “How would the homeowner describe the quality of the inspection of the

roof and voids by the installer's surveyor?”

Remarks: the chart shows a quite even level of satisfaction in the inspection of the

roof condition. However, people cannot evaluate this objectively, because not many

owners have the technical knowledge to understand the issues involved in the

inspection.

43

4.1.8 Q.8

In this question the researcher asked the householder if the roof has been

reconditioned and strengthened in order to support the extra loads.

Chart 13 Roof reinforcing

Question 8: “According to age and type of structure not all roofs need to be reinforced

prior to fitting the solar panels. Did the installers reinforce the existing roof structure?”

Remarks: is evident that roofs within the current research have not been reinforced in

order to support the loads of the solar panel modules. The reality confirms the

perceptions from the author that few premises have been strengthened before

retrofitting the panels – only 2.86%.

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4.1.9 Q.9

The following question perhaps has a technical approach, but is well explained to

homeowners; however, people spread the answers according to their knowledge. This

is a key issue which in many occasions is misunderstood by homeowners living in

exposed southern areas of the city, near the Peak District (where the current study

predominantly took place).

Chart 14 Wind effect issues

Question 9: “In the Sheffield area the effects of the wind is not uniform due to its

geography. Does the occupier know that the wind can significantly increase the weight

load of the roof coverings?”

Remarks: A high percentage of the sample responded to understand the issue, but

the majority do not bother or do not consider that it is important. Answers “No” and

“Don’t Know” total 57.14 % of the sample.

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4.1.10 Q.10

The question inquires the number of people who have rented out the signed the FiTs

for certain amount of years to a third party against the total of households from the

sample

Chart 15: Renting out the roof area

Question 10: “Does the householders rent out their solar panel array?”

(A third party leasing the roof for certain amount of years)

Remarks: From the sample is evident that the socio-economic factors influenced this

question; most of the properties visited belonged to the upper middle-class were the

availability of extra funds has been redirected to the solar system. Only 2 houses had

benefited from free- installations 5.71%. This could change radically if the sample is

obtained from Sheffield, S14.

46

4.1.11 Q.11

This question is related to the previous number 10. It enquires if the occupier has taken

the advantage form the FiTs.

Chart 16 Taking advantage from Fits

Question 11: “If the answer to 10 is "NO", did the homeowner take advantage from

the FiTs?”

Remarks: the chart shows the evidence of how the FiTs have impacted in the decision

to purchase (or lease to a 3rd party) the mentioned technology at a high proportion of

88.57%. “Not applicable” correspond to PVtp owners. The answer “No” corresponds to

an installation from 2007.

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4.1.12 Q.12

In this question, similar than number 10, we are more specific and enquiry if they

leased the roof to a supplier. This is because in some cases the previous owner from

the house can pretend to carry on with the FiTs contract, even that he is not the owner

of the house. This is not usual, but it is allowed.

Chart 17: Renting out to a solar supplier

Question 12: “If the answer to 10 is "YES", did the homeowner lease the roof space to

a solar company supplier?”

Remarks: Only 2 people had rented their roof to the company who installed them

(5.71%). The chart shows that the influence of the FiTs has promoted the PVsp

systems, even that numerous homeowners do not get much energy from their panels,

because they are not at home during daylight hours. For them a better option is the

PVtp system (8.57%).

Most people own the panels in the area (85.71%).

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4.1.13 Q.13

The interviewer asked about the influence of the FiTs in the final decision to acquire

this technology. Before 2010 no many people had them installed.

Chart 18: Influence of the FiTs

Question 13: “Did the FiTs (introduced in 2010) influence the decision to install the

solar panel array?”

Remarks: The FiTs has been the most important source for installations of solar

system (80%). People who installed the PVsp before 2010 (11.43%) have made their

decisions based in the benefits of a clean environment and due to a surplus of

resources; they paid 200% more at that time. The rest have only PVtp (8.57%).

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4.1.14 Q.14

People may change the house when finding a new job, get ill or when children move

out of the house, etc. This question was designed to investigate this issue, and

peoples’ responses were positive and reasonable.

Chart 19: Thinking ahead

Question 14: “Before making the decision to purchase the system; did the occupier

consider the years in which he / she will expect to live in the house?”

Remarks: Most people considered this issue (80%). Combining “No” &” N/C” makes a

20% of householders who did not regard this as important.

50

4.1.15 Q.15

Households were asked to describe the insurance cover for the PV system. In many

occasions they could not remember if they have insurance. In the case of renting out

the roof space, this is covered by the company who leased the roof.

Chart 20: Insurance covering

Question 15: “If the occupier purchased the solar panel array; has his / her home

insurance covered the system at no extra cost?”

Remarks: the sample shows that 48.57% of households are covered by their

insurance without paying extra money. 42.86 % cannot recall if they are covered.

8.57% are not covered.

People are not sure because in most cases they did not tell the insurer about the new

installation. They ‘assume’ they are covered and this is a misconception. It is like a

purchase of an appliance.

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4.1.16 Q.16

Question 16 is close to Question 15. People are asked the same question with a

different order to check the accuracy of the response. Option “No” in Q.16 is similar to

option “Yes” on Q.15. Option “Don’t Know” on Q.16, was the option “Not Sure” in Q.15

Chart 21: Necessity to purchase insurance

Question 16: “Has the occupier had to purchase a different insurance policy or

increase cover of their current policy to cover the system?”

Remarks: the results shows that 85.71% said that there was no need to buy a different

policy or increase the premium in the existent policy. 11.43% Don’t Know. One

household pays more for the insurance

From the difference between Q15 and Q16 is possible to deduce that people did not

tell the truth.

a- People who answered “YES” on Q.15, should have answered “NO” in Q16

b- People that have answered “NOT SURE” on Q.15 should have answered “DON’T

KNOW” in Q16

a Discrepancy 37.14%

b Discrepancy 31.43%

The installer has also highlighted this issue during the interview. See in Appendix 9.4

Table 10:

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4.1.17 Q.17

Households were asked about the perception that properties with PV will increase the

value. This is a question about aesthetics.

Chart 22: expectation of better value

Question 17: “Does the occupier believe that the solar panel installation will increase

the value of the property?”

Remarks: People really value their properties, 65.71% believe it will boost the

prospect of selling the house. 25.71 % don’t know and 8.57 % do not agree it will

increase the value of the house.

53

4.1.18Q.18

Households were asked about the level of satisfaction with the system.

Chart 23: Level of satisfaction

Question 18: “How satisfied is the occupier with the solar panel system?”

Remarks: Most people are very satisfied with the systems, with 66% of the sample

affirming that. The satisfied rate is 34%.

No negatives responses were received.

54

4.1.19Q.19

According to the brand fitted, the units have an efficiency of around 15% to 20% (power

of the PV module per unit of area), this is determined by manufacturers. The

householder should be advised in this regard by the installer.

Chart 24: Efficiency

Question 19: “In terms of efficiency, is the level of energy generated as accurate as it

was predicted before the installation?”

Remarks: 71.43 % asserts that the units work according to estimates. Installers

provide homeowners with a table containing the forecasted efficiency per annum.

55

4.1.20Q.20

In this question the households are asked about legal issues; this is mostly focused in

people who rented out the roof to a company supplier.

Chart 25: Types of ownership

Question 20: “If the occupier wanted to sell the property and he / she is not the owner

of the solar system, will he / she consider purchasing the remaining years of the lease

from the company who installed them?”

Remarks: as predicted people answered N/A. 32 of them purchased the units

according to the questionnaire sample.

The only 2 households who rented out their roof space to a third party answered:

A) Said that he will “Not” consider purchasing back the panel system if he wants to sell

the property.

B) Answered that this question is “Not Applicable” for him.

These are not the expected responses from the people who rented out the roof. This is

a legal point. They do not know exactly which are the legal terms of the lease contract.

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4.1.21Q.21

In this question the households were asked if they will invest again in the systems,

adding new modules or replacing the actual ones.

Chart 26: Replacing or increasing covering

Question 21: “Are planning to replace or increase your solar panel array in the next 1 -

5 years?”

Remarks: most people answered “No” (94%), mainly because the systems last up to

30 years. Manufacturer’s warranty covers up to 20 years. The question was to know if

people were willing to install other type of system, for example PVtp.

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4.2 Interviews to Homeowners

Most people preferred to complete the hard copy questionnaire. However, 12

homeowners accepted to have an unstructured interview. These are non-statistical

answers.

Copies from the manuscripts can be seen in Appendix 9.2

Interviews highlights:

1- Being able to reduce the consumption by 20% during summer;

2- Get free energy while at home;

3- Have an investment with a high return (6 to 7% per annum), for households with

generation high tariff;

4-Tax free;

5- The equipment is guarantee for 10 years;

6- Do not need maintenance [IT WILL DO AT SOME STAGE];

7- Efficiency is better than predicted;

8- Installing 6.4kW of capacity and exporting just the 50% of the energy produced to

the grid can help to reduced up to 50% from the households bills;

Downsides:

People working outside his home most of the time do not make the best use of the

system.

As the FiTs are reducing payments it is better not to expect a high return.

Homeowners should consider the fitting of PVtp as well (Energy Saving Trust 2015).

They can provide most of the hot water needs for a house, instead of selling cheap

energy to the grid.

Households did not check if the roof has been properly reinforced and secured by the

installer.

In many cases homeowners don’t know if they are covered by the home insurance due

to the omissions to inform the insurers.

Homeowners did not receive in all cases the right information from the systems.

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4.3 Interview to MRICS Valuer

Interview to Andrew Winters from Blundells 10-8-2015

See appendix 9.3

He answered the following questions:

Table 8: Responses from questions 1 to 5

Table 9: Responses from questions 7 to 12

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4.4 Interview to a Solar Panel Installer

Interview to Robin Atterton from Mack Installation 14-8-2015

This was an unstructured interview where mainly technical issues were asked

Important for Surveyors: See appendix 9.4

Roof assessment

Rafter thicknesses, compliance to Eurocode 5

Nogging additions

Bracketry and fixing, screws in the incorrect position

Attaching solar modules to slates

Array design.

4.5 Interview to Building Surveyor See appendix 9.5

Interview to Phil Parnham from Blue Box Partners 21-8-2015

He has answered the following questions.

Fig. 13: Questionnaire responses.

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Fig. 14: Questionnaire responses.

4.6 Other consultations

The authors consulted other professionals; Flint Ross, A J Marsh and Chandlers

Building Surveyors.

Chandlers from Holmesfield replied saying that on a few occasions they did work for

clients requiring calculations of the roof structure capacity for installing solar panels.

They said that people did not like when they advised the clients not to install, because

the roof had a weak structure to support the array.

On the 19th of August the authors had a conversation with Mr Ralph Bennett from the

Sheffield City Council Building Standards in which he expressed the position from the

council in that regard. (See appendix 11.6)

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4.7 The Authors Findings

Examples of miscalculations

At the start of the current dissertation the idea of failure of PV installations was

theoretical, based on assumptions made from the non-compliance with the legislation

in place and the MCS Guide (2012) for PV installers. The author observed numerous

solar arrays where, non-minimum margins have been kept. In this case the array

covers 90 % of the surface. The roof has concrete tiles. The following Pictures have

been taken during the current research.

Property A, Pict 1 West facing view Pict 2 In detail

Pict 1 shows that the panel comprises the whole length of the slope. This is a 2 storey

house in an exposed and hilly area in the city. Pict 2 shows concrete tiles without

pointing. Metal clips are lose and the verge needs rebedding. The danger is that the

tiles are lose at the edge of the wall and there is nothing to hold the roof against the

uplifts forces

Pict 3 Sagging process Pict 4 Damage in detail

In Pict. 3 & 4 the roof has suffered from the effects of the weak structure and the action

from the wind. As the rails are fixed by rows, the movement has cause the panel to split

into two different sections. Pict 4 shows a displacement downwards from the bottom

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row of almost 18 mm from the alignment to the slope axis. This roof needs an

immediate assessment. The questions to ask here is: who inspected the roof before

the installation took place? And who bears the cost of repairs?

Property B, Pict 1 Pict 2

Property B has similar problem, the colour lines show the different alignment from the

two pieces. The long axis of the house is facing South and prevalent wind from Left

(west) the ridge is showing a bending process. The roof is covered with slate tiles

Pict 3 Cantilevered panels

A wrong design can end like this. Insufficient number of anchors can leave the last row

without the appropriate support. The wind will exert stronger up-lift forces in that side of

the panel.

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Property C, Pict 1

This is a sigle storey house with a loft convertion. In this case the roof is covered with

clay tiles and the location of the property corresponds to the lower area of S17. The

array has a west facing orientation. Under the 16 modules array is posible to visualize

how high has been fitted to the roof, that situation enhance the up lift forces from wind

Pict 2 In detail

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Chapter 5. Results

In Chapter 1, 1.5, the author set out a number of questions which were designed to

meet the objectives. The following section will answer those questions:

a) Can PV solar panel installations damage the integrity of the roofs coverings?

The presented literature, Ridal et al. (2010), Zapfe (2011), and the (MCS Guide 2012),

point 4.3.7 in page 25, was suggesting that the thickness of the trusses was already an

issue at the time to incorporate extra loading. Therefore, the building examples of failed

roofs, combining three different kind of covering materials and weights provided by the

authors validate the truth of the previous assertions. Yes, solar panel installations can

damage the integrity of the roofs.

b) Is the principle of permitted development for PV installations a green light for

unscrupulous installers?

The author considers that the principle of permitted development is an arguable issue:

In one hand is the legislation from cities like Norfolk in Canada, where any solar panel

installation above 5m² requires a planning application, prioritising safety. In the other

hand is the British legislation which allows individuals to install solar panels without any

restriction, except for conservation areas and listed buildings. The results are starting

to be seen, and it does not look right. Yes, the permitted development principle has

been used by dishonest individuals and should be re-examined.

c) Before fitting the PV panels, do installers take account of the real condition of

the roof structure?

This raises the question of needing a qualified structural engineer to assess the loading

capacity of the roof. And so the question should be:

Is the MCS approved installer able to structurally assess the roof while simultaneously

being qualified to do the electrical and mechanical parts of the installation? No. The

author does not agree the MCS installer can do everything.

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d) Is the PV installation insured in all cases?

Because the MCS approved installer is not a charted engineer, it is possible that

insurers could use this as grounds not to pay insurance claims arising from fault or

miscalculations of the loadings.

From questions 15 and 16, it was found that households retain the information about

the fitting of the PV system; there is a misconception that the solar array comes with all

the insurances. The results of the mentioned questions gives ground to believe that an

important number of households do not have insurance for the PV array.

5.1 Answering the Hypothesis:

Are PV systems a hidden source of liability for building professionals?

It would be valuable to separate each statement.

The technology has come to stay, but requires a frame where all the stakeholders

know which are the rules to apply. The examples in chapter 4 give an idea of the

market. Surveyors will evaluate the complexity of each case and will provide advice

strictly within their competences.

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Chapter 6. Conclusions

Arguably, people have not taken into account their responsibility to inform their home

insurer about the installation of a new PV system.

The idea of that a property will have more value for the fact of having a solar panel

(65.71%), confronts the valuer declaration in that regard. He gave an example saying:

If you have two similar houses, one with a solar array and one without. People will like

to buy the one without the solar arrays, why? Because people don’t like them. He

added saying: the only case they will buy the house with the installation it is in the

case it is incorporated into the tiles, because aesthetically looks better (See Appendix

9.3)

Chapter 7. Summary

The study intends to bring a light to an issue that is really concerning for building

surveyors and public in general:

-The environmentally friendly perception of solar panels confronts the reality of

the lack of strength of a number of properties in which they are installed.

-Who can determine which properties can have or not the devices installed?

After the pictures provided in chapter 4, there are some questions regarding the

professionals who advised those householders.

In addition, the misinformation from the house holders and the absence of clear

guidance regarding the insurance cover for the devices could jeopardise people’s

safety.

8. Suggestions and further studies

1) Re-validation from the installer’s competence for structural, electrical and

mechanical calculations

2) Verifying the position of the insurers in this regard if they will find a reason not to pay

if installers are incompetent.

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3) To revise the standard size for timber especially the sizes for rafters, as the future

may require stronger structures due to the necessity to incorporate new low carbon

technologies.

End of the study

Ernesto Correa 4 of September 2015

Sheffield Hallam University