MAPEI introduces Mapeguard UM, a crack-suppression, waterproofing and vapor-pressure-equalizing underlayment membrane approved for use with latex-modified mortars as part of a warranted system for the installation of ceramic tile and natural stone. Because Mapeguard UM equalizes vapor pressure, it can be applied over young concrete in fast-track construction or concrete with high relative humidity. The lightweight membrane can also be applied over single-layer plywood floors.