We had a delivery of floor tile today. As we are also replacing a floor in an existing bathroom and using varied sizes and colors in the studio, there are many different boxes. Suki, the Inspector, crawled under the plastic and reported the order was accurate and complete!
A mastic is applied to the floor first. After drying to a "tacky" state, the membrane is applied. Billy is using a heavy roller to smooth out any air bubbles or ridges, and Robert is cutting and peeling the next section of membrane.
The actual membrane material comes in rolls with a paper backing. Accurate measurement and careful placement is necessary. Once it touches the floor, there is no tolerance for movement or replacement. A steady hand is required. Both the installers are well experienced.
Installation of a membrane such as "Mapelastic" is recommended prior to ceramic tile placement. Although it's an added expense, the material provides important insurance against the shrinkage of the new floor. The underlayment will absorb cracks up to 3/8 inch and not allow the tile to follow the crack in the cement pad. We'll see.