I have 60 mm of Solid Oak 180x18 to go in new extentions on top of concrete, damp course and 8cm of screed on top.
Which is the correct way to lay floor, please?
P.S. The area is spread over four rooms, biggest being 8m x 6m
We recommend installing the floor floating - any slight unevenness of the screed floor can be much better tackled this way than with fully glueing the floor down. Also, install every room separate (especially when two connecting rooms differ very much in width or have a small door opening) and install wooden thresholds in between.
Lay a DPM and sound-insulation underlayment first (look for a combi product) to prevent any residue moist from the screed going into the wood. The board can be installed on top of the underlayment, glueing the T&G's completely.
Rule of thumb for expansion gaps: 3mm per meter width of the room, minimum of 10mm all around. For the room that is 6m wide this should be at least 18 - 19mm. Cover expansion gaps with flat beading or skirting (thick enough to cover the gap of 19mm, plus leaving extra thickness for possible skrinkage).