DELTA®-PT / DELTA®-LATH Insulates and isolates damp and contaminated walls, vaults, and basements. The Guaranteed Solution. The ‘Original’ Waterproof Membrane System. DELTA®-PT has been specially designed with damp control in mind. Dampness, which is found in many older properties, can be easily controlled using DELTA®-PT or DELTA®-LATH. DELTA®-PT is a special high performance polyethylene membrane which is extruded into a series of studs. The purpose of the studs is to create a continuous air gap behind the waterproof membrane. On the face of the membrane a welded mesh allows plasters and renders to bond efficiently to achieve dry and durable finishes. DELTA®-PT is watertight, resistant to high and low temperature extremes, chemically resistant to acids, alkalis, oil and solvents and is approved for use in drinking water applications.