NCC Version:
NCC 2022 Volume Two
Area of NCC Requirements:
Section H – Health and Amenity
- H2P1 Rainwater Management
- H2P2 Weatherproofing
- H2P3 Rising Damp
Problem:
The dwelling’s blockwork basement walls are located below the natural ground level. The NCC 2022 does not provide Deemed-to-Satisfy (DTS) solutions for weatherproofing in such below-ground wall scenarios. Without a compliant solution, water ingress, rising damp, and poor rainwater management could lead to structural damage, unhealthy conditions, or loss of amenity for future occupants.
Solution:
A performance solution was developed using expert judgment and comparison with the British Standard BS8102:2022, a widely accepted benchmark for below-ground waterproofing. The solution combines three waterproofing types—barrier (Type A), integral (Type B), and drained (Type C)—through the use of membranes, waterproof concrete additives (e.g., Xypex, Penetron), drainage systems, and protective detailing. This layered approach is designed to achieve Grade 3 water tightness, which means no water ingress or dampness is permitted, suitable for habitable spaces.
Finalised Report:
The report concludes that the proposed below-ground wall design meets the NCC’s performance requirements for rainwater management, weatherproofing, and rising damp. The assessment confirms that the combination of materials and construction techniques provides an effective and compliant waterproofing system. The performance solution has been verified through expert judgment and satisfies all required criteria.