Thermoplastic and vinyl asbestos tiles were very often laid on ground floor subfloors that did not incorporate a damp proof membrane. The adhesive was unaffected by moisture and the tiles allowed the passage of moisture vapour. Modern formulations of vinyl tiles are considerably more sensitive to moisture vapour. It is therefore essential that the presence of a damp proof membrane is confirmed. If not then it will be necessary to remove all of the adhesive, apply a suitable waterproof surface membrane, prime and apply a smoothing compound.
If the subfloor is protected by a membrane it will be necessary to expose about 70% of the base screed, then prime with neat Stopgap P131 before applying a minimum 3mm thick skim of a suitable smoothing compound.
Thursday, March 24, 2016