What is Type A waterproofing?

Type A waterproofing, often called 'Barrier Protection,' involves applying a waterproof material to the internal or external surfaces of the structure. This blocks water ingress physically. Examples include external adhesive membranes applied before backfilling (positive side) or internal multi-coat rendering/tanking slurries (negative side). While effective, Type A relies 100% on the workmanship and substrate preparation; a single defect can lead to failure, which is why we often combine it with other systems.