Isolation membrane is a durable material installed underneath ceramic tile floors to protect them from becoming cracked due to heavy foot traffic. This material can also be used to patch small individual tile cracks as well as to cover an entire subfloor. Adding isolation membrane is a straightforward process with a few basic tools and tips.
Clean the Subfloor First
Thoroughly wipe down the subfloor with a damp cloth, and allow it to dry before spreading on any mortar for the isolation membrane. Removing any dirt and debris allows the isolation membrane to lay flat, and prevents uneven spots once the membrane is installed.
Use the Width of the Membrane as a Guide
Check the manufacturer's instructions for your isolation membrane; some types require a bonding material other than standard mortar. Note the width of the membrane material, and spread the mortar along a section of the wall only as wide as the isolation membrane.
Use a Straightedge
When rolling out the isolation membrane along the floor, fit it snugly against the wall by using a straightedge to clamp it down. Also, trim off any excess material at the same time with a utility knife along the straightedge. This will ensure there are no gaps between the isolation membrane and the bottom of the wall.