The Damptec team are currently waterproofing a new build lower ground floor extension in Tideswell in the Peak District, Derbyshire. Tideswell sits in a locality with the highest category for Radon and the waterproofing system therefore required the inclusion of radon gas protection.
We recommended a combined waterproofing system for the full run of the walls as there is a potential risk of water building up behind the structure, as follows:
- Type A: Barrier Protection – internal waterproofing
- Type C: Drained Protection – internal waterproofing
Internal: Type A (Barrier) Protection
We applied a Type A waterproofing ‘barrier’ system to the internal blockwork structure, bund and R/C floor. The included:
- Application of primer to all surfaces in a spray coat.
- Ffillet seals at the base of the bund using repair mortar.
- Application of Newton Hydrocoat Tanking Slurry, a cement-based protective waterproof membrane, to the internal surfaces (see first photo).
Internal: Type C (Drained) Protection
Secondary protection, which manages any water ingress which occurs as a consequence of an installation defect, is provided by a cavity drain membrane system.
The effectiveness of the waterproofing system is dependent upon discharging free water before pressure can build up behind the system.
Gravity drainage is to be installed via a waterproof bund to run the full length of the building including the rear and both sides (90 mm wide). The drainage channel runs around the perimeter.
Wall Cavity Drain and Gas Barrier Membrane
Walls: we fixed Newton 508 (8mm) cavity drain membrane and gas barrier to the internal side of the walls and taped it into the wide DPC.
Stage 2 – Once the internal blockwork has been erected the Damptec team will return to site to carry out the following work:
Waterproofing the R/C concrete floor
We will be installing the Newton 508 8mm cavity drain floor membrane and radon barrier over the concrete floor in conjunction with cornerstrip. Newton floor membrane is an internally applied flooring membrane that isolates moisture-sensitive flooring from.
Radon detailing
When waterproofing work includes radon protection the detailing is vital. All joints must be double taped, double sided and over-taped. Multiplugs are also over patched with Over Tape.
23rd March 2026
Tideswell
