01/04/2026
British Standard for waterproofing existing basements
Waterproofing Existing Basements - What Does the British Standard Recommend?
BS 8102:2022 states that every existing basement will face water pressure at some point in its life. No one can predict when this will happen because future rainfall, watercourse changes, and burst water mains remain unknown variables. It’s also extremely risky to assume water will never exert pressure on a basement.
The British Standard also recommends the waterproofing designer to expect—and design for—a full head of hydrostatic water pressure in almost every case. So how do we protect against such a scenario?
Type C waterproofing is defined as "drained protection" by the British Standard. The approach receives incoming water within internal voids formed by cavity drain membranes and strategically positioned drainage channels on the floors and walls. The system depressurises that water as it enters and then moves it safely out of the building.
Because Type C waterproofing is maintainable and reliable, professional waterproofing contractors often choose it as the safest method. Designers also frequently use Type C in combination waterproofing designs for both existing and new basement structures.
Our CDM System is an example of a maintainable Type C solution built on decades of waterproofing expertise. Comprising of high-quality, BBA-certified membranes with dedicated pumping systems, battery backup and telemetry, this proven approach has transformed hundreds of existing basements into dry, usable living spaces.
Strategically placed inspection hatches also allow inspection, cleaning and targeted remedial work without major disruption. This ensures the design considers the feasibility of inspection, maintenance and remediation from the outset, as required by BS 8102:2022.
Credit to our Specialist Basement Contractor Dampco for the Type C installation to this existing basement in the South West.
Read the full article here: https://www.newtonwaterproofing.co.uk/help-advice/waterproofing-existing-basements/
