UNIVERSITY OF NAIROBI

DEPARTMENT OF CIVIL AND CONSTRUCTION

ENGINEERING

To investigate the extent of use of expanded polystyrene panels for

building construction in Kenya

By: Njuguna Simon Gitau

F16/2291/2009

A project submitted for the partial fulfillment for the requirement for the

award of the degree of

BACHELOR OF SCIENCE IN CIVIL ENGINEERING

2014

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Abstract

Kenya is currently facing a housing deficit due to an increasing middle class and a slow

rate of construction of houses. Some of the reasons causing this deficit are the high cost of

construction, long time taken to finish projects due to unpredictable weather conditions, varying

workmanship on site and unexpected hiking of material costs. Introduction of new building

technology, that uses expanded polystyrene panels, has led to reduction of the time and costs

spent in construction of houses while producing housing products with innovative, modern and

green credentials. This method of housing was officially approved by the Kenyan government in

2004 and has brought higher output capacity enabling realization of important projects.

This project sought to investigate the extent of use of the expanded polystyrene panels for

construction in Kenya and assessed the strength of expanded polystyrene wall and slab panels. It

also compared the time and cost incurred when constructing using the expanded polystyrene

panels and conventional methods using machine cut masonry stone, and how this method of

construction conserves the environment. The study approaches that were used are questionnaires,

site visits and photography, interviews, desktop studies and minor lab tests to ascertain the

information received about the strength of the expanded polystyrene panels. .

It was concluded that the use of the expanded polystyrene panels for construction in

Kenya is yet to gain momentum. The study proved that expanded polystyrene wall and slab

panels are strong enough to be used for construction of walls and floor slabs in buildings and

conserves the environment. A time saving of 50% and cost saving of 30% though labor, transport

and hiring of construction equipment and formwork, are being achieved.

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Dedication

This piece of work is dedicated to my dear parents, brothers and sisters who have always

believed in me and encouraged me through my education. Thank you for your unrivaled support

and prayer throughout.

Most thanks to The Almighty God who has abided with me through the ups and downs and

enabled me to achieve victory.

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Acknowledgement

Special thanks to my supervisor Eng. Mrs. Monicah Gathoni Wokabi for her continuous and un-

ending informed advice. Your effort at providing advice to me is greatly valued.

To Nicholas and Muchina of the concrete Lab University of Nairobi, your support and guidance

was of great value.

To Lillian Kageni who was my partner in researching about expanded polystyrene in Kenya,

may you have success in your project and career.

To all my classmates and friends whose company and team spirit enriched my stay at the

university, may God bless you all. You will be missed.

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Table of Contents

Contents

Chapter 1

1.0 Introduction ............................................................................................................................... 1

1.1Background information ........................................................................................................ 1

1.2 Introduction to study ............................................................................................................. 2

1.3 Problem statement ................................................................................................................. 2

1.4 Objectives of the study .......................................................................................................... 3

1.5 Methodology ......................................................................................................................... 3

Chapter 2 ......................................................................................................................................... 5

2 Literature review .......................................................................................................................... 5

2.1 General .................................................................................................................................. 5

2.2 Introduction to construction with expanded polystyrene panels ........................................... 5

2.2.1 Expanded polystyrene ..................................................................................................... 6

2.2.2 Material requirements ................................................................................................... 16

2.2.3 Casting methods ........................................................................................................... 17

2.3 Factors to consider when commencing construction on site using polystyrene ................. 18

Chapter 3 ....................................................................................................................................... 24

3 Methodology .............................................................................................................................. 24

3.1 Questionnaires ..................................................................................................................... 24

3.1.1 Questionnaire for engineers using expanded polystyrene panels for building ............. 24

3.1.2 Questionnaire for engineers not actively using expanded polystyrene panels ............ 25

3.1.3 Questionnaire for home owners not using expanded polystyrene panels ..................... 25

3.1.4 Questionnaire for members of the public not using expanded polystyrene panels ...... 26

3.1.5 Questionnaire for home owners using expanded polystyrene panels ........................... 26

3.2 Site visit and photography ................................................................................................... 26

3.3 Interviews ............................................................................................................................ 26

3.4 Minor lab tests to assess strength of panels........................................................................ 27

3.4.1 Structural characteristics of expanded polystyrene wall panels ................................... 27

3.4.2 Structural characteristics of expanded polystyrene slab panels.................................... 29

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3.4.3 Workability Determination ........................................................................................... 30

Chapter 4 ....................................................................................................................................... 32

4 RESULTS AND ANALYSIS .................................................................................................... 32

4.1 Extent of spread of construction using expanded polystyrene panels in Kenya ................. 32

4.1.1 Data analysis: Engineers and contractors using expanded polystyrene panels ............ 32

4.1.2 Data analysis: Professionals not yet using expanded polystyrene panels .................... 36

4.1.3 Data analysis: Home owners not yet using expanded polystyrene panels ................... 37

4.1.4 Data analysis: Members of the public not yet using expanded polystyrene panels ..... 39

4.1.5 Data analysis: Home owners using expanded polystyrene panels ............................... 40

4.2 Data analysis: Interviews .................................................................................................... 41

4.3 Desktop studies ................................................................................................................... 42

4.3.1 Shrinkage Cracks .......................................................................................................... 42

4.4 Assessment of the strength of expanded polystyrene wall and slab panels ........................ 47

4.3.1 Reason for use of quarry chippings in shotcrete........................................................... 47

4.4 Cost analysis of building using expanded polystyrene panels ............................................ 51

4.4.1 Material cost ................................................................................................................. 51

4.4.2 How use of expanded polystyrene panels reduces the cost of construction ................. 55

4.5 How use of expanded polystyrene panels conserves the environment ............................... 59

4.5.1 Saving on energy spent during construction................................................................. 59

4.5.2 Saving on energy spent during the lifetime of the house ............................................. 60

4.5.3 Other ways thism method conserves the environment .......