Type A Waterproofing
/type-ay WAW-ter-PROO-fing/
Also known as: Type A system, barrier waterproofing, tanking, bonded waterproofing, cementitious waterproofing, crystalline waterproofing
Definition
One of three basement waterproofing system types defined in BS 8102. Type A (barrier protection) uses applied membranes or coatings bonded directly to the structure to prevent water ingress. Includes cementitious slurry, crystalline systems, sheet membranes, and liquid-applied membranes.
In Practice
Type A systems rely entirely on the membrane remaining intact and bonded to the structure. Any crack or failure allows water in with no secondary defence. For this reason BS 8102 recommends that below-ground Type A systems are combined with Type B (structurally integral) or Type C (drained cavity) approaches in high-risk or habitable situations. Type A is most suitable for above-ground tanking and Grade 1 (utility) basement environments.
UK Building Regulations
BS 8102 - Protection of Below Ground Structures
BS 8102:2022 classifies systems as Type A (barrier), Type B (structurally integral), and Type C (drained). For Grade 2+ basements the code recommends combining system types. CSSW-qualified specialists should design the waterproofing strategy.