One common category is defined by the physical form of the material.
Sheet-Based Membranes are pre-formed, flexible rolls (like bituminous, PVC, or EPDM sheets) that are anchored or welded together to create a continuous barrier, ideal for large, uniform areas like foundations and flat roofs.
Liquid-Applied Membranes, on the other hand, are coatings that are sprayed, rolled, or troweled on, curing to form a seamless, joint-free layer that is perfect for complex shapes and details like bathrooms, balconies, and roofs with many penetrations.
A subset of this is Cementitious Waterproofing, a rigid, cement-based coating that is easy to apply but best for internal, non-moving surfaces like water tanks and swimming pools.
For new construction, Integral Systems are highly effective, where crystalline admixtures are mixed directly into the concrete, making the concrete itself water-resistant throughout its mass.
Finally, Bentonite Clay systems use panels of highly absorbent clay that swells when wet to form a dense, self-sealing gel barrier, often used on below-grade foundations.