BS 8102 is the British Standards Institute Code of Practice for Protection of Below Ground Structures Against Water from the Ground. The code gives recommendations and guidance on methods of dealing with and preventing the entry of water from surrounding ground into a structure below ground level – e.g. basements.

Although the principles contained within the code are still sound, after over twenty years, BS 8102:1990 Code of Practice for Protection of Structures against Water from the Ground was overdue for revision. Firstly, the Code is now called BS 8102:2009 Code of Practice for Protection of Below Ground Structures against Water from the Ground. In this article we look briefly at some of the key changes in the standard and what they mean for those looking to waterproof a basement…

Design team to include a waterproofing specialist

The code recommends “A waterproofing specialist should be included as part of the design team so that an integrated waterproofing solution is created. The waterproofing specialist should:

• be suitably experienced;
• be capable of devising solutions that accommodate the various project restraints
• and needs;
• provide the team with information and guidance that assists and influences the design, installation and future maintenance of the waterproofed structure.” 

It goes on to say “…The waterproofing specialist could be a manufacturer or material supplier, provided that the manufacturer/supplier has the relevant expertise”

Assume water pressure to the full height of the basement

From the waterproofing point of view, the code is now quite clear. Regardless of the decision made by the structural engineer as to the position of the water table, the waterproofing specialist has to allow for some water pressure (from saturated ground) to the full height of the basement.

Meaning of the term ‘defects’

The code now recognises that there are two types of defect: defects owing to poor workmanship or inappropriate use of materials and defects owing to the specific properties of the materials being used.

Type C grade now includes cavity drainage membrane

The original code recognised Type C as the most reliable system, but it did not include the currently used cavity drainage membrane systems. The revised code recognises the place that membranes have in Type C and includes a great deal more detail on their installation, as well as accentuating the importance for ongoing maintenance.

The three different types of system quoted in BS 8102 are:

• Type A: Barrier Protection
• Type B: Structurally Integral Protection
• Type C: Drained Protection

Conclusion

Once architects have taken on board the need for a waterproofing specialist on the design team, defective designs should be reduced. Furthermore, where unacceptable leakage occurs as a result of defects, it should be possible to undertake remedial work without having to completely strip out the basement, as is often the case at the moment.

Furthermore, it should be much easier for waterproofing specialists to comply with the code, as it is clearer, less ambiguous, and more flexible in terms of what can and cannot be done.

Finally, it is worth noting that it is not a statutory requirement to comply with this (or any) BSI code. However, when things go wrong and law suits start flying, the first thing the courts look at is compliance with relevant codes. If a design does not comply with the appropriate code, the designer will need to justify why it does not comply. In short, it is easier to comply with the relevant codes in the first place and, with this new code, it should be easier.

This article was written by Timberwise. The national property care organisation specialise in dampness and waterproofing issues within properties.

 

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