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 · NW3
Basement waterproofing in Hampstead.
Hampstead has the most distinctive geology of anywhere we work in London, and the most misunderstood. Sand caps the hill, clay sits beneath it, and water moving down through the permeable sand meets the impermeable clay and emerges as a spring line. Both the Fleet and the Tyburn rise here. Homeowners reasonably assume that the highest ground in London must be the driest, and on Hampstead it is very often the opposite.
Ground conditions
What sits beneath Hampstead.
| Postcodes | NW3 |
|---|---|
| Geology | Bagshot Sand and Claygate Beds capping London Clay |
| Groundwater | High and persistent — a spring line runs where the sands meet the clay beneath |
| Housing stock | Georgian and Victorian houses on steep plots, large detached villas |
Perched water above the clay and steep plots together produce strong lateral seepage through uphill-facing walls. This is drained protection territory almost without exception — a tanking slurry against that head is asking a barrier to do something it was never designed for.
Hampstead is one of the areas we cover across North London.
Specification
Choosing the right system for Hampstead.
BS 8102 sets out three forms of protection. Which one suits a property in Hampstead 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.