Sheet membrane underlayments are thin and lightweight. They come in a roll and are often made of a
flexible foam or rubberized asphalt sheet. Membranes that are “peel & stick” have an adhesive backing with a release paper on one side. They can be used in a variety of applications with membranes made specifically for use under tile and stone flooring, wood flooring, and other specific materials. Some membranes are only to be used for horizontal applications, such as floors, while others may be used in vertical applications like around doors and windows. Many are approved for use over radiant heated floors.
Tile & Stone Flooring
Membranes designed as an underlayment for ceramic tile or stone floors will typically provide
anti-fracture resistance and crack suppression in the horizontal movement of the substrate or subfloor. This will help to protect tile and stone susceptible to cracking. These membranes are often vapor barriers that will help to prevent mold from growing under the tile and other problems that can be caused by moisture. Some will also provide impact and sound reduction or additional thermal insulation.
Wood & Laminate Flooring
Some sheet membranes are designed to be an underlayment for engineered wood plank, wood parquet, and laminate floors, providing a barrier for air and moisture. Membranes that are
air and moisture barriers can protect wood flooring from common problems such as warping. Similar to membranes for use under tile and stone, sheet membranes to be used under wood can also provide sound reduction and thermal insulation.
Easy to Install
Sheet membranes are easy to install. Typically, they can be applied to a variety of substrates including plywood, concrete, cement backer board, and other common materials used for substrates. An appropriate primer should be used before installing the membrane - most manufacturers have a primer specifically for use with their product.
After applying the primer, the membrane can be put in place and cut to the correct length. Once the membrane is in place, the appropriate thinset, modified thinset, or mortar can be applied, and the tile, stone, wood, or other material installed on top.