Type A
Barrier protection
Cementitious slurries and spray applied membranes, forming a continuous barrier against the structure. Suitable where the structure is sound and the head of water is modest and well understood.
Hand & spray applied
Areas we cover · CR8
Basement waterproofing in Purley.
Purley lies in a dry valley that is only dry some of the time. When the Chalk aquifer recharges after a run of wet winters, the water table can rise many metres and the Bourne resurfaces — flooding cellars that have been bone dry for a decade. Waterproofing here has to be designed for the wet years, not the year of the survey.
Ground conditions
What sits beneath Purley.
| Postcodes | CR8 |
|---|---|
| Geology | Chalk, on the floor of a North Downs dry valley |
| Groundwater | Strongly seasonal — the Bourne runs in wet years and not at all in dry ones |
| Housing stock | Large Edwardian villas, many with original cellars, plus 1930s stock |
The Edwardian villas along the Brighton Road corridor frequently have original cellars worth converting, but they need Type C drained protection rather than a tanking slurry given the head of water involved.
Purley is one of the areas we cover across Surrey & the North Downs.
Specification
Choosing the right system for Purley.
BS 8102 sets out three forms of protection. Which one suits a property in Purley depends on the water head, the condition of the structure and what you intend to use the space for.
Type B
Structurally integral
Water-resistant concrete construction, with joints and service penetrations designed as part of the structure. Usually the route for new basements and underpinned extensions.
New build & underpinned structures
Type C
Drained protection
Cavity drain membrane, perimeter channel and a pumped discharge. It manages water instead of resisting it, and it remains maintainable — which is why it suits most conversions of existing cellars.
Maintainable · Grade 3 habitable
Nearby
We also work in these areas.
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Book a survey in Purley.
Tell us what you're seeing and we'll tell you honestly whether it needs a full waterproofing system or something much simpler.