A waterproof membrane is a continuous liquid or sheet applied barrier installed to block liquid water from passing through concrete, decks, or below grade walls. It protects the structure independently of the concrete itself.
A waterproof membrane is a continuous layer of material, liquid applied or sheet applied, installed to block water from passing through concrete, decks, or below grade structures. It works as a barrier system rather than relying on the concrete itself to keep water out.
Types of Waterproof Membranes
Liquid applied membranes are rolled or sprayed on and cure into a seamless, rubber like coating, which makes them well suited to complex shapes and penetrations. Sheet membranes are pre manufactured rolls installed with overlapping seams, often used on large flat roofs or below grade walls where speed of installation matters.
Waterproof Membrane vs. Vapor Barrier
A waterproof membrane stops liquid water under hydrostatic pressure, such as on a balcony, planter, or below grade wall. A vapor barrier, by contrast, blocks water vapor from migrating through a slab from below, which is a different problem that calls for a different product.
Practical Tips for Installing Waterproof Membranes
Always follow the manufacturer’s cure time before installing a topcoat or flooring system over a membrane, and pay close attention to detail work around drains, corners, and penetrations, since that is where most failures start. Flood testing before final finishing catches leaks while they are still easy to fix.
