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 · CR3
Basement waterproofing in Caterham.
Caterham has one of the best-documented groundwater flooding problems in the South East. The Caterham Bourne emerges when the Chalk aquifer is charged, and valley-floor properties have seen repeated below-ground flooding. This is not a damp-proofing job — it is a water-management job, and it needs a drained cavity system with properly specified pumping and battery backup.
Ground conditions
What sits beneath Caterham.
| Postcodes | CR3 |
|---|---|
| Geology | Chalk of the North Downs dip slope |
| Groundwater | High risk — the Caterham Bourne is a known groundwater flooding source |
| Housing stock | Victorian terraces in the valley, inter-war and post-war housing on the slopes |
For valley-floor properties we specify twin-pump sump chambers with independent battery backup as standard. A single pump on mains power is not adequate protection here.
Caterham is one of the areas we cover across Surrey & the North Downs.
Specification
Choosing the right system for Caterham.
BS 8102 sets out three forms of protection. Which one suits a property in Caterham 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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Tell us what you're seeing and we'll tell you honestly whether it needs a full waterproofing system or something much simpler.