BS 8102 Waterproofing Regulations

Every single waterproofing specialist who works for Timberwise must understand and abide by the regulations contained within BS 8102: 2022.

The principles and ideas contained within the previous iteration of the BS 8102 codes (BS8102: 2009) are still sound, but they have been revised and updated, and are now published under the name BS 8102: 2022: The Code of Practise for Protection of Below Ground Structures Against Water Ingress.

BS 8102 Waterproofing Regulations

Every single waterproofing specialist who works for Timberwise must understand and abide by the regulations contained within BS 8102: 2022.

The principles and ideas contained within the previous iteration of the BS 8102 codes (BS8102: 2009) are still sound, but they have been revised and updated, and are now published under the name BS 8102: 2022: The Code of Practise for Protection of Below Ground Structures Against Water Ingress.

The Fundamentals of BS 8102:2022

If a basement waterproofing system is to be successful and effective following its installation the following factors must be taken into consideration.  

• The use of a suitably qualified and experienced designer as part of the team.
• It must be determined who is to take on responsibility for the waterproofing design.
• The carrying out of risk assessments (sewers, gases, trees).
• Investigation of the water table and surrounding areas.
• Accessibility, repairability, and servicing of the waterproofing system.

Whilst the BS 8102: 2022 code is not specific about the qualification the Waterproofing Design Specialist requires, the Property Care Association (PCA) has created a Waterproofing Design Consultant Qualification to properly accredit those working as Waterproofing Design Specialists (WDS). Those who achieve the WDS qualification can be found on the PCA register.

Design teams will be able to call on these consultants to assist and advise with waterproofing elements in the designs of new properties.

Key Legislation & Codes of Practice

• Health & Safety at Work Act 1974
• The Management of Health & Safety at Work Regulations 1992
• The Environment Protection Act 1990 (EPA)
• BS 8102 – Code of practice for protection of below ground structures against water ingress.
• BS 8384: 2015 – Code of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings.
• BS8301 – Code of practice for building drainage.
• BS8110 – Structured use of concrete. Part 1: Code of practice for design and construction.
• BS8007 – Code of practice for the design of concrete structures for retaining aqueous liquids.
• The Ciria 139 Report – – Water resisting basements.
• The Ciria 790 Report – Flood resistance.
• National House Building Council – NHBC standards volume 1 1991 Chapter 5.3
• Building guarantee technical manual – Section 3 & 13 Clause 13.5.

BS 8102 – Risk Assessment

A risk assessment must be carried out on waterproofing projects to highlight short and long term issues that might arise as a result of the works. The risk assessment should consider the effects of surface water infiltration, the use of external drainage, and cut off walls.

When designing a waterproofing system the following must be considered from the planning stages:

1. The effects of climate change, burst water mains and sewers, adjacent trees, sulphates, radon, methane, and other ground cases and contaminants.
2. Where external drainage is proposed, the effects of drawdown on adjacent structures, the potential silting of drainage and biofouling issues.
3. Even when the site investigation indicates dry conditions, the risk of some water logging in the future must be assumed.

BS 8102 – Risk Assessment

A risk assessment must be carried out on waterproofing projects to highlight short and long term issues that might arise as a result of the works. The risk assessment should consider the effects of surface water infiltration, the use of external drainage, and cut off walls.

When designing a waterproofing system the following must be considered from the planning stages:

1. The effects of climate change, burst water mains and sewers, adjacent trees, sulphates, radon, methane, and other ground cases and contaminants.
2. Where external drainage is proposed, the effects of drawdown on adjacent structures, the potential silting of drainage and biofouling issues.
3. Even when the site investigation indicates dry conditions, the risk of some water logging in the future must be assumed.

BS 8102 Fundamental: Waterproofing Designer

BS 8102 requires a suitably qualified Waterproofing Specialist to be a part of the design team from the outset.

This Waterproofing Specialist should be properly accredited and experienced, with them having achieved at least the qualification of being a Certificated Surveyor in Structural Waterproofing (CSSW).

The Waterproofing Specialist will also be responsible for providing the design team with guidance that assists and influences the overall design, installation, and the future maintenance of the structure which is being waterproofed.

It is very important that from the beginning of the project someone must be liable for the design of the waterproofing system overall.

A Waterproofing Specialist Designer Will:

• Be able to advise and be a useful part of the team.
• Take on design liability if required.
• Carry out risk assessments (sewers, gases, trees, etc).
• Investigate the water table and the surrounding areas.
• Consider accessibility, repairability, and servicing.
• Design to the required environment grade for basement usage (Grades 1a, 2b, 2, or 3).
• Choose the correct method or type of waterproofing system to utilise (Type A, B, or C).

BS 8102 – Water Pressure

BS 8102 clearly states that the waterproofing specialist has to allow for some water to the full height, and to 150mm above external ground levels where practically possible – regardless of the water table.

The hydrostatic head from a water table (whether it be natural or perched) is there for the structural engineer, who must design the structure to resist the water pressure present.

BS 8102: 2022 gives more freedom to the structural engineer to interpret the maximum head he needs to design for.

BS 8102: 2022 does not give a specific source of the water it mentions. It leaves that open to apply to situations at hand, but some of the most obvious sources include burst water mains, damaged drains, or even heavy rainfall.

BS 8102: The Defects

Defects within a properties waterproofing can often be attributed to poor work during construction, but this can be avoided with the use of skilled workers, proper design, and thorough planning.

BS 8102 now recognises that there are some defects that may not be avoided as they are inherent within the materials being used, and they cannot be avoided. During the design process consideration must be given to the potential of defects after the construction is complete, and how they could potentially be amended if needed.

NHBC (National House Building Council) Chapter 5.4

Due to the increased number of claims on properties, the NHBC have developed their own waterproofing guidelines, which apply and effect any new or existing below ground constructions, covering:

• Basements
• Lift pits
• Cellar split levels

The NHBC has also set up minimum requirements and standards for their own individual property warranties.

Other Guidelines

Because of the increase in the number of claims on properties, Premier Guarantee and the Local Authority Building Control (LABC) have also developed their own waterproofing guidelines.

Both of these guidelines (both LABC and the Premier Guarantee) re-enforce the waterproofing guidelines set out in BS 8102.

For More Information

If you would like any more information on the waterproofing regulations or if you have any waterproofing problems then don’t hesitate to get in touch with our team of waterproofing specialists at Timberwise. You can do this by calling on 0800 288 8660 or you can request a survey online. A survey through Timberwise is the starting point to designing a successful waterproofing system for your property.