We are converting our garage into a living space, the floor construction is DPC, 2inch insulation and 10inch slab. We need to make up the floor level by 160mm. We are told we can just skim over with self-leveling as the floor isn't that bad, directly lay 120mm Kingspan, then lay directly ontop caberdeck, thne overlay with our floor finish. Would this be acceptable? Do we need additional vapour barriers or screed to lay the insulation in? Any help would be greatly appreciated.
How to install floor insulation
- Thread starter plugy
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I'd do it - 1200g polythene (turned up the wall) - 75mm Celotex - the rest floor screed. No need so self level the floor.
Yes.
Yes. Un-boded screed needs to 75mm deep.
The argument is that the insulation will help pay for itself, therefore the more the merrier. I'm sure though, that there comes a point where adding more thickness becomes ineffectual.
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Particularly if you start having to ventilate to allow air circulation. The difference between .25 and .19U in a garage might be something like £20 a year, so if it costs another £600 thats quite a wait for payback.
We are looking for the easiest and quickest way. We have been told to self level, 120mm of insulation no wet trades then overboard. No need for a DPM as there is one under the raft. Other question is shuld we dot and dab the plasterboard and skim before laying the floor?
No need for self-levelling under the insulation. If it is uneven, consider using sand to level it up.
Celotex and/or Kingspan have documents describing how to do it that you can find online. A couple of points, which some may consider unnecessary, are: put a wooden batten around the edges, and put a polythene “slip layer” between the insulation and the chipboard.
Who did? It's quicker and easier not to self level.
It matters not. Would you rather be scraping the concrete floor or scraping the timber deck? Do you mind having to pack the plasterboards on bricks etc whist bashing them back into place?
So reading through it appears we have a couple of choices, these would be on the basis of easiest to achieve, cheapest and material availability as we need it done sooner than later.
What does everyone think of the options and are they doable?
Bearing in mind the exsisitng makeup of the floor, DPM, 2inch insulation, 10 inch slab. This was the level garage floor. now we raised by a coarse of bricks and installed bi fold doors, so need to raise the floor 160mm to be level or just below the door threshold with a finished covering. (wooden or carpet)
1. Self level floor, lay DPM, insulate 110mm celotex (dearer option for insulation), caber deck. Self level 5mm, DPM, 110mm insulation, 22mm caber deck, 10mm underlay, 10mm floor covering
2. Screed with dry sand/cement (making up the 10mm difference to use cheaper 100mm jabfloor), DPM insulate with 100mm jabfloor, caber deck. 15mm screed, DPM, 100mm jablite, 22mm caberdeck, 10mm underlay, 10mm floor covering.
Ideally need to use 110mm insulation but expensive £40-£50 per sheet, appose to jablite £20 per sheet but only comes in 100mm. So bit more work to make up the difference with screed but enabling the use of cheaper more readily available insulation.
Any thoughts?
What does everyone think of the options and are they doable?
Bearing in mind the exsisitng makeup of the floor, DPM, 2inch insulation, 10 inch slab. This was the level garage floor. now we raised by a coarse of bricks and installed bi fold doors, so need to raise the floor 160mm to be level or just below the door threshold with a finished covering. (wooden or carpet)
1. Self level floor, lay DPM, insulate 110mm celotex (dearer option for insulation), caber deck. Self level 5mm, DPM, 110mm insulation, 22mm caber deck, 10mm underlay, 10mm floor covering
2. Screed with dry sand/cement (making up the 10mm difference to use cheaper 100mm jabfloor), DPM insulate with 100mm jabfloor, caber deck. 15mm screed, DPM, 100mm jablite, 22mm caberdeck, 10mm underlay, 10mm floor covering.
Ideally need to use 110mm insulation but expensive £40-£50 per sheet, appose to jablite £20 per sheet but only comes in 100mm. So bit more work to make up the difference with screed but enabling the use of cheaper more readily available insulation.
Any thoughts?