How to insulate & laminate an existing concrete floor in 65mm

[Pete574]

I am in the process of planning a bathroom conversion whereby I would like to insulate an existing 14 square meter concrete floor:

1. I have 65mm to work with (otherwise I need to raise the door height).
2. There is an existing DPM layer
3. 65mm includes insulation/chipboard/laminate

I am currently thinking of a 50mm GA4000 Celotex + 10mm tongue and groove laminate flooring

Does this sound like a sensible approach? Are there other Celotex-like products I should consider?

My main concerns are the compressibility of the Celotex. i.e. would 10mm of laminate flooring distribute the load sufficiently to prevent deformation?

 

[Tigercubrider]

Not an expert but I suspect so.
I helped a mate do a garage conversion and we used 50mm rock wool ( very dense) and glued chipboard t&g to form a raft. This was a recording studio so the floor was independant from the walls.

 

[Notch7]

am currently thinking of a 50mm GA4000 Celotex + 10mm tongue and groove laminate flooring

Does this sound like a sensible approach? Are there other Celotex-like products I should consider?

My main concerns are the compressibility of the Celotex. i.e. would 10mm of laminate flooring distribute the load sufficiently to prevent deformation

I dont think that would work.

I would suggest, insulation, T&G chipboard flooring with joints off set from insulation layer, then laminate flooring.

 

[Pete574]

40mm Celotex + 18mm P5 T&G chipboard + 10mm laminate flooring = 68mm height

68mm should still mean the door height can stay the same.

Cheers.

 

[Notch7]

40mm Celotex + 18mm P5 T&G chipboard + 10mm laminate flooring = 68mm height

68mm should still mean the door height can stay the same.

Cheers.

Yes that would work well.

Foil tape on the celetex is always worth doing, it forms a complete vapour barrier and increases air tightness. I use the 75mm diall tape from screwfix.

A decent laminate underlay gives a nice solid feel.

This website has a few good options
https://www.tradepriced.co.uk/timbertech2_acoustic_gold_laminate_underlay.html

 

[Pete574]

Agree with adding underlay, but will need to reduce the insulation:

30mm Celotex + 18mm + P5 T&G chipboard + 5mm underlay + 10mm laminate flooring = 63mm

 

[Notch7]

Agree with adding underlay, but will need to reduce the insulation:

30mm Celotex + 18mm + P5 T&G chipboard + 5mm underlay + 10mm laminate flooring = 63mm

Be careful with the insulation thickness if its critical -the last batch of 25mm I got was only 22mm.

If you dont want to compromise insulation, you could use a thin 2mm underlay. I have to say though, the acoustic underlays do give a better, more solid feel to the floor, much better than the cheap foam you can buy.

 

[foxhole]

Laminate in a bathroom?

 

[Pete574]

@foxhole: They do have some laminate suitable for bathrooms:
https://www.ukflooringdirect.co.uk/laminate-flooring-aqualock-8mm-farmhouse-oak
@Notch7: If I go for the 40mm insulation, then my height will increase to 73mm which will mean raising the door height. Hence the 30mm insulation. However, I will verify the insulation height before installation.

 

[foxhole]

Only moisture resistant, will still fail with a bad leak.

 

[Pete574]

If we don't notice the leak in time, then you are correct in that it will fail. We did consider vinyl as well - this has the benefit of having very little height and moisture proof - however, we haven't found any we like yet.