Structural Waterproofing Design Strategies to BS 8102:2009

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NEWTON WATERPROOFING SYSTEMS ©Newton House, 17-19 Sovereign Way, Tonbridge, Kent TN9 1RHT: 01732 360095| E: [email protected]| W: www.newtonwaterproofing.co.uk

STRUCTURAL WATERPROOFING DESIGN STRATEGIES TO BS 8102:2009

ISO 9001ISO 14001OHSAS 18001

Certificate Number: 12252

PROTECTING BUILDINGS SINCE 1848

Presented by:Richard Crossley CSSW, WDS Technical Director

10/10/2016 4Newton Waterproofing Systems ©

The importance of BS 8102:2009 and how to design waterproofing systems

Types of waterproofing systems used to protect structures internally and externally

Different levels of waterproofing protection in the UK explained

Failed basements – why failures happen and how to deal with the problem using Cavity Drain Membrane Systems

The importance of using a professional waterproofing contractor (NSBC) for design and installation who can offer a guarantee for their work

Newton Waterproofing Systems head office, Tonbridge“To provide an overview on the types of systems utilised to provide protection to below ground structures from water from the ground in the UK.”

AIM OF TODAY’S STRUCTURAL WATERPROOFING SEMINAR

Newton have extensive training facilities


NEWTON INVENTED THE FIRST CAVITY DRAIN MEMBRANE - “NEWTONITE” - 1932


COMPREHENSIVE RANGE OF WATERPROOFING SYSTEMS


DESIGNING A WATERPROOFING SOLUTION: THREE DEFINING FACTORS

Consideration to the recommendations of BS 8102:2009

What form of structure you are intending to use

What is the internal space going to be used for

Three Defining Factors

When looking at waterproofing solutions there are three defining factors:


BRITISH STANDARD 8102:2009

BS 8102:2009

The Code of Practice for the Protection of Below Ground Structures Against Water From the Ground


BS 8102:2009: Code of Practice for the protection of structures against water from the ground

ICE: Reducing The Risk Of Leaking Substructures (A Clients Guide)

CIRIA 139/140: Water Resisting Basement Construction

Reference Material

REFERENCE MATERIAL


The National House Building Council (NHBC) have clarified the recommendations of BS 8102:2009 with the introduction of the new Chapter 5.4 ‘Waterproofing of basements and other below ground structures’.

The new Chapter introduces meaningful benchmarks and supporting technical guidance for a range of situations where the structure is required to resist the ingress of water from the ground and other sources, where ‘normal’ waterproofing arrangements are not considered appropriate.

NHBC: Chapter 5.4 ‘Waterproofing of Basements and other Below Ground Structures’

NHBC: CHAPTER 5.4


Design Philosophy and Design Team

The Standard recognises that, for a below ground project to be successful, strategies for dealing with groundwater, soil gases and contaminants are considered from the very earliest stages of the design process

A “Waterproofing Specialist” should be included as a part of the design team so that an integrated waterproofing solution is created

All design decisions made by others that might have an impact on the waterproofing design should be brought to the attention of the waterproofing/ specialist designer and installing contractors. Final decisions and any recommendations should be approved by the designer.

BS 8102:2009 - DESIGN PHILOSOPHY AND DESIGN TEAM

If a Waterproofing Design Specialist is not involved in the design, the designer is culpable


SITE ASSESSMENT: DESIGN TO HIGH WATER TABLE

Design To Expect A High Water Table

A risk assessment should be carried out which considers the long term pressures, the effects of surface water infiltration and the use of external drainage, cut-off walls and the local geology and topography both recent and historical.In addition, consideration should be made for: burst water mains and sewers, adjacent trees, sulphates, radon, methane and other ground gases and contaminates.

“Even when the site investigation indicates dry conditions, the risk of some waterlogging in the future should be assumed.”

“Even in a permeable subsoil, ground water requires time to drain away and this can result in limited pressure periodically coming to bear against the structure.”

Waterproofing measures should be designed on the basis of water to the full height of the retained ground at some point in the structure’s life.


BS8102:2009 TYPES OF WATERPROOFING SYSTEMS

Protection against water ingress by a ‘barrier membrane’

applied to the structure

Type A Protection

‘Structurally integral’ joint seals and maintainable

interjoint protection against water transmission

Type B Protection

An internally maintainable

‘drained system’ with dedicated ground water

discharge management

Type C Protection




Type C Protection




Type C Protection


Multilayer systems

Can be one or two part systems

TYPES OF WATERPROOFING: TYPE A (BARRIER) PROTECTION

Type A (Barrier Protection)

Has no integral protection against water penetration and relies totally on a waterproofing membrane to keep water out.

Liquid Waterproofing Membranes

External Waterproofing and Drainage Membranes


Newton System 200

TYPES OF WATERPROOFING: TYPE A (BARRIER) PROTECTION

Type A (Barrier/Tanked Protection)


TYPES OF WATERPROOFING: TYPE B (INTEGRAL) PROTECTION

Type B (Integral Protection)

Requires that the structure itself be constructed as an integral water-resistant shell.

Waterbars, Waterstops and Waterplugs


One-part system


Type BWaterbars provide Type B protection



Type B (Structurally Integral Protection)


Type C (Drained Cavity Protection)

Incorporating a drained cavity within the structure.

TYPES OF WATERPROOFING: TYPE C (DRAINED CAVITY) PROTECTION

Professionally installed internally after construction of basement

Provides zones of depressurisation at strategic points in the structure

The most effective and trouble free standalone waterproofing system

Cavity Drain Waterproofing


TYPES OF WATERPROOFING: TYPE C (DRAINED CAVITY) PROTECTION

Type C (Drained) Protection: Cavity Drain Waterproofing


A. The likelihood of leaking is highB. The consequences of leakage is

unacceptableC. Unacceptable water vapour

transmission could otherwise occur

Combination Waterproofing Systems

BS 8102:2009 advises that a Combined Waterproofing System be considered where:

TYPES OF WATERPROOFING: COMBINATION SYSTEMS

Consideration should be given to the type of combined protection i.e.

Type A and Type B Type A and Type C or Type B and Type C

A typical combination waterproofing design showing Newton System 500 cavity drain system internally (Type C) and Newton System 400 membrane externally (Type A)


GRADES OF WATERPROOFING PROTECTION


OUTWING VS WEATHERALD HIGH COURT CASE

Outwing vs Weatherald

A very high profile case which has set a precedent in the waterproofing industry. The end ruling of the case states that it is not reasonable for a tanking system to be applied 100% defect free. This means that if you are using a system which has to be 100% defect free as your only waterproofing system, and it fails, you can be held responsible.


Case Study: Tanking System Failure

Project Overview: £12m house in Fulham

Scenario Builder installed a cheap waterproofing solution

Why It Went Wrong: Wrong product, installed in the wrong place – on the inside rather than the outside. Areas such as wall/floor junction ignored

Consequences of Failure: Burst water main led to water pouring into the property. Tens of thousands of pounds of damage

Could Have Been Avoided: If a Cavity Drain Membrane System had been installed to manage ingressing water

FAILURE: TANKING SYSTEM


POSITIONING OF TYPE A MEMBRANES


Case Study: Type A ‘Sandwiched’ Design Failure

Project Overview: Existing Commercial Project

Scenario: A single Type A waterproofing system was installed here.

Why It Went Wrong: No consideration was given to the ‘form and feasibility of remedial treatment’

Consequences of Failure: When the system failed, there was no way to detect where the failure so there was a great deal of disruption caused by trying to locate and fix the problem.

Could Have Been Avoided: Installation of a Cavity Drain System would have included specially designed inspection ports to locate any problems. In addition, the Cavity Drain System would have depressurised the water meaning that water ingress would be minimal, even if the system was damaged

FAILURE: TYPE A ‘SANDWICHED’ DESIGN


Case Study: Multiple System Failure

Project Overview: Large Scale Multi-Level New-Build Basement, London

Scenario: The two forms of waterproofing system used here were Type A ‘Barrier’ Protection and Type B ‘Integral’ Protection

Why It Went Wrong: Failure of Type A system and caused flooding, water level rose to 5 feet internally!

Consequences of Failure: Very high cost of remedial work, plus project delayed by many months

Could Have Been Avoided: A Waterproofing Specialist would have designed a Combination Waterproofing System to negate any risk of water ingress – probably a Type A, B and C System for a project of this size

FAILURE: COMBINATION SYSTEM


FAILURE: STANDALONE SYSTEM

Case Study: Standalone System

Project Overview: Existing Building, Basement Conversion to Office Space

Scenario: Installation of a Type A System – consideration has not been given to the type of structure to which it was applied

Why It Went Wrong: Water pressure created tensile bending stresses causing the internal floor slab to lift and break

Consequences of Failure: Damage was extensive and costly – both in the cost of remediation work and due to the fact that the office needed to be out of service until it was fixed.

Could Have Been Avoided: A Type C Drained Cavity System should have been used to depressurise water, and a supporting Type A system would have been recommended to give even more robust protection.


This flow chart from BS 8102:2009 outlines the principal factors and stages that need to be addressed in order to produce a robust waterproofing solution for a below ground structure

PRINCIPAL FACTORS FOR WATERPROOFING DESIGN


A Type C maintainable solution is ideal for new-build basements and refurbishment projects. The System comprises four components: Cavity Drain Membranes, Drainage, Pumps and Control Systems.

TYPE C WATERPROOFING – THE ULTIMATE CONTINGENCY PLAN


NEW-BUILD WATERPROOFING DESIGN – TYPE B & C COMBINED

Type C cavity drain system internally, Type B waterbars to construction joints


NEW-BUILD DESIGN COMBINED NEWTON SYSTEMS – TYPE A & C

Type A bonded sheet membranes externally, Type C cavity drain system internally


THE COMPLETE BASEMENT SYSTEM NEW-BUILD TYPE A, B & C

Type A bonded sheet membranes externally, Type B waterbars in the construction jointsType C cavity drain system internally,


PODIUM DECK & ROOF WATERPROOFING DESIGN


LISTED BUILDINGS REQUIREMENTS

Damp proof membranes are installed throughout Windsor Castle

Listed Building Requirements

Section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990, states that ‘no person shall execute or cause to be executed any works for the demolition of a listed building or for its alteration or extension in any manner which would affect its character [emphasis added] as a building of special architectural or historic interest, unless the works are authorised’. The fundamental challenge when dealing with buildings of special architectural or historic interest is therefore to maintain structural and aesthetic integrity, whilst remaining sympathetic in the product application and still achieving the desired effect. Damp proofing and cavity drain membranes can be sympathetically applied with little or no preparation at all and depending on the chosen wall finish, often only require the very minimum of strategically placed fixings to hold the membrane in place. They could – if ever required – be removed at a later date so the building could be restored to the original condition, which also meets Listed Building recommendations for being a reversible solution.


LISTED BUILDINGS – CASE STUDY

Type C cavity drain system installed internally

Case Study: The Royal Courts of Justice

This Grade I listed structure had a labyrinth of unused basement areas. With space at a premium, a large part of the brick basement area was converted into habitable space.

A full Type C Cavity Drain System was installed by a Specialist Waterproofing Contractor. The System was quick to install and sympathetic to the structure, making it the ideal waterproofing solution.

The convoluted Victorian Bird Beak Arches were sympathetically waterproofed whilst retaining the original features of this historic property, thus meeting Listed Building Requirements. The vaults are now fully refurbished and provide a habitable area to Grade 3 of the environmental table within BS 8102:2009

Following the success of this project, the Specialist Waterproofing Contractor was commissioned to complete a second area to the same specification, with plans to renovate further areas of the immense below ground infrastructure in the future.


RAPID REOCCUPATION FOLLOWING FLOODING

Flood rescue by the British Army and the Mountain Rescue at Queens Staith Road near the Ouse Bridge in York City Centre

after heavy rain, on 27th December 2015

Rapid Reoccupation Following Flooding

Lord Deben, Chairman of the Committee on Climate Change recently stated: “climate change is expected to increase the frequency and magnitude of severe flooding across the UK”

Defences that might historically have provided protection against a 1 in 100 year flood will, with climate change, provide a much lower level of protection and be overtopped more frequently. The latest projections suggest periods of intense rainfall could increase in frequency by a factor of five this century as global temperatures rise.

A saturated wall can take up to a month per inch of its thickness to dry out and even with dehumidifiers, heaters and air changing units this process can still be painfully slow and inhibit any successful reoccupation for a prolonged period of time.

The installation of cavity membranes can speed up the reoccupation of flood affected buildings as they can be installed while the wall is still damp. The membrane will form an impermeable barrier which separates new finishes from the damp structure so the new wall finishes will not be affected by the salts and staining which could occur during the drying process.


RAPID REOCCUPATION FOLLOWING FLOODING

Ingressing water is expelled using a sump and pump system - and the homeowner could stay in

his property

Case Study: Designing A Flood Mitigation SystemSouth Hinksey, Oxfordshire suffers from high flood risk. In 2007, a major flood engulfed the village with devastating results.

A full Cavity Drain System was installed in five properties in the village. Sump and pumps were installed to manage any ingression of water through the building fabric and through the floor to the sump and pump systems so problem water could be evacuated in the event of ingress.

With the major flood in Oxfordshire in November 2012 these systems were tested to the extreme, with 500 to 800mm of water engulfing the village completely. The Cavity Drain System protected all the properties it was installed in, while houses all around were flooded and in some cases families were evacuated from their homes.

“My friends and family were amazed how well the system did exactly what it was supposed to. Following the event, I have not had to claim on my insurance, I have not had to clean up or had any stress put on me, as my home was saved. My neighbours whom had not installed the flood protection were devastated at the amount it is going to cost them to repair the damage caused by the flooding, the stress it caused and is causing and the sheer turmoil it leaves behind” – Detective Sgt Maria Banks, Local CID, Oxford Police Station.


NEWTON SPECIALIST BASEMENT CONTRACTOR (NSBC) NETWORK

Newton Specialist Basement Contractors (NSBC) are an elite group of professional structural waterproofing contractors who work in partnership with Newton Waterproofing Systems to provide the specifier and their clients with the highest quality products, design and installation available in all aspects of domestic and commercial basement waterproofing

NSBC contractors can offer peace of mind to the designer and the client by taking full design liability on the project, and can fulfil the role of ‘waterproofing design specialist’ as recommended by BS 8102:2009

All members of the scheme adhere to very strict membership criteria. NSBCs are required to demonstrate the ability to deliver quality design and workmanship, resulting in a meaningful scheme where all members provide a level of superior technical excellence unsurpassed within the industry


NEWTON SPECIALIST BASEMENT CONTRACTOR (NSBC) NETWORK

At Newton Waterproofing Systems we take our responsibility to protect and preserve the environment very seriously and are committed to the prevention of pollution. Therefore we strive to use the most environmentally friendly materials and processes in all of our activities.

We are committed to being compliant with all environmental legal requirements, any other requirements to which we subscribe, to using all our resources wisely and to disposing of waste responsibly.

Planning and control of our processes is documented in our quality and environmental management system in line with ISO 9001:2008 (Quality) and ISO 14001:2004 (Environmental) Standards.

Newton Waterproofing Systems are the first construction industry supplier to gain full membership into RECOUP, the UK’s leading authority on plastics waste and resource management.


NEWTON TECHNICAL DESIGN SERVICE

In-house CAD design service

3D sections and details available

BIM objects for insertion into your project

NBS Create and NBS Building used in-house to produce bespoke specifications tailored to your project

Newton Waterproofing APP features all our product datasheets, case studies and technical drawings

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NEWTON WATERPROOFING SYSTEMS ©Newton House, 17-19 Sovereign Way, Tonbridge, Kent TN9 1RHT: 01732 360095| E: [email protected]| W: www.newtonwaterproofing.co.uk

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ISO 9001ISO 14001OHSAS 18001

Certificate Number: 12252

PROTECTING BUILDINGS SINCE 1848

Structural Waterproofing Design Strategies to BS 8102:2009

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