Foundation Waterproofing Sheet Membrane
This information reflects our best understanding of product composition in 2021.
Sheet membranes are commonly used to waterproof below grade structures such as foundations, though may also be used to waterproof tunnels, earth shelter structures, split-slab construction, and decks. The main advantage of sheet membranes, as...
Sheet membranes are commonly used to waterproof below grade structures such as foundations, though may also be used to waterproof tunnels, earth shelter structures, split-slab construction, and decks. The main advantage of sheet membranes, as opposed to cementitious waterproofing or liquid applied membranes, is their consistent thickness. These membranes also have good elongation and flexibility to move with the building. The most common sheet membranes are self-adhering rubberized asphalt membranes. They are comprised of a polymer film laminated to a rubberized asphalt adhesive which is covered by a release liner for peel-and-stick application. The membrane comes in a roll and can be applied horizontally or vertically. A primer is required on concrete prior to application of the membrane. Once the membrane is applied, it must be rolled with a hand roller to ensure a complete bond to the substrate. Some products have a selvage edge of asphalt adhesive to aid in sealing between sheets, but in order to ensure continuity, sheets must be overlapped by a minimum of 2-3 inches and the seams rolled to ensure adhesion. Some products may require additional sealing at corners or edges or additional protection from damage. Care must be taken not to damage the membrane during backfill.
A historical version of this CP is available here: https://pharos.habitablefuture.org/common-products/2214301.