Floor preparation

Every floor finish comes with a tolerance in the small print, and almost every failure we are called to comes from ignoring it. Engineered boards and laminate want the floor flat to about 3mm over a two metre straight edge. Large format tiles want it flatter still, and sheet vinyl or luxury vinyl tile shows every trowel mark and grain of grit underneath within a month. So preparation starts with measuring: a straight edge and a laser across the room to find the high and low spots, and a moisture meter on every concrete floor. A new sand and cement screed dries slowly, roughly a day for every millimetre of the first 40mm and longer after that in a cold Irish winter, and a floor laid on a damp screed cups, lifts or grows mould under the vinyl. High spots are ground off, low ones filled with a levelling compound poured to a feather edge, and cracks are cut out and repaired. Timber subfloors get the same attention in a different way. Loose and squeaking boards are screwed down into the joists, split or rotten ones replaced, and where tiles or vinyl are going on top the boards are overlaid with plywood, screwed at close centres so nothing moves. With underfloor heating the system is run through its commissioning cycle and switched down before anything is laid. Last come the membranes and underlays chosen for the finish and the heating, and a check that every door will clear the new floor height.

Old floor tiles and black adhesive

Thermoplastic and vinyl floor tiles in houses from before the 2000s, and the black bitumen adhesive under them, can contain asbestos. We do not break them up to find out. If we suspect it, a sample goes for testing first. If the result is positive the tiles are removed by a licensed contractor, or left in place and sealed under a new plywood overlay, which is often the simpler answer.