The following measures, along with proper installation and good construction practices, are proving helpful in putting a cost-effective end to moisture-related flooring and coating problems on new construction projects.
1. Determine ahead of time if moisture mitigation will be necessary. Review the installation requirements for the flooring or coating material to be installed and determine whether there is sufficient time, and favorable enough conditions, for the slab to dry naturally to the levels required. Consider that the drying of conventional concrete does not begin until the surface of the slab is not exposed to topical sources of water and the surface is open enough for internal moisture to escape. If it is determined, or if there is any doubt, that there is not enough time or favorable conditions for the slabs to dry naturally to the levels required, a moisture mitigation strategy will be necessary. An approach that allows implemention at the beginning of the construction process should be considered.
2. Take the ground completely out of play with an ASTM E1745-compliant, Class A vapor retarder with the permeance requirement lowered to 0.01 perms after conditioning.
3. Place the vapor retarder directly beneath the slab and incorporate design and construction measures necessary to minimize any potentially adverse effects of placing concrete directly in contact with the underside of the slab (such as curling, cracking, or dominant joint activity).
4. Calculate in advance the amount of deflection anticipated for elevated slab placements and provide ample provision in the budget for the amount of leveling material that will be necessary to bring the floor levelness to what’s specified.
5. When moisture mitigation and floor leveling is undertaken early in the construction process, the slab should be protected from freezing, topical sources of water, traffic damage, and contamination throughout the remaining construction process.