NCC Version:
NCC 2019 Volume 2, Amendment 1.
Area of NCC Requirements:
P2.2.1: Rainwater management
P2.2.2: Weatherproofing
P2.2.3: Rising damp
Problem :
There are no Deemed-to-Satisfy (DTS) provisions within the NCC for waterproofing blockwork basement walls that are positioned below ground level. This absence creates a compliance gap in ensuring the structure remains protected from rainwater, surface water entry, rising damp, and related moisture issues which could cause deterioration of building materials or create unhealthy internal conditions.
Solution:
A performance solution was developed based on British Standard BS8102:2022 and expert judgment. The design incorporates a combination of Type A (barrier protection) and Type B (structurally integral protection) waterproofing strategies. These include the use of core-filled blockwork walls with Xypex or Penetron additives, Wolfin membrane systems, under-slab polythene, granular backfill, agricultural drains, and corflute protection sheets. This layered approach is designed to achieve Grade 3 watertightness, suitable for habitable basement spaces.
Finalised Report:
The report concludes that the performance solution satisfies the NCC 2019 Volume 2 Performance Requirements P2.2.1, P2.2.2, and P2.2.3. The proposed waterproofing strategy is deemed adequate through expert evaluation, analytical comparison to BS8102:2022, and a detailed installation methodology that ensures long-term protection against moisture ingress.