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Carpentry & Joinery
Building raised floor off of concrete slab
Just had garage rebuilt off existing concrete slab and wishing to put laminate/solid wood flooring in.
DPC is three courses high so I know I need to raise floor to at least that height. The garage is being converted into a utility area and has already been partitioned.
What method works best for ensuring damp doesn’t rise through to flooring? I’ve seen a mixture of celotex and plain timbers with insulation between.
Does the slab need DPC’ing? Or a vapour barrier installing?
For the brickwork, should I insulate those up to the three courses?
Thanks!
1 Answer from a MyBuilder Carpenter & Joiner
Hello, sounds like you will be installing a floating floor. You need to make sure the concrete slab is level; if it's not use a levelling screed. Then install a Damp Proof Membrane (DPM) 1200 gauge, with joints lapped and and folded over to prevent moisture coming up. This should be brought up the sides to connect with the DPC. Lay your insulation boards, butt jointed together. Install a separating layer which is a polythene sheet 1000 gauge; joints lapped and taped and brought up the sides of the perimeter wall by about 100mm. Then lay 22mm tongue and groove chipboard. And finally your laminate floor finish. If you have a cavity wall, that is likely to be insulated; but if it's just a single skin of brick you would need to insulate the whole wall.
Answered 1st Oct 2018
