floating floor for limestone - Tile Advice

[jonnyc]

i have just seen a job today where there is an existing floating subfloor consisting of 50mm insulation sitting on concrete and then a 18-22mm chipboard overlay.
this was fine when carpet installed on top.
new owner wants limestone.
there is room for 30mm build up on top of existing chipboard and stone is 12mm thick.
any suggestions of how to best give a good solid build up from concrete up, on which to lay limestone.
my initial thoughts are need to keep some insulation but create a non floating subfloor .

 

[widler]

flaoting floor for limestone

Can you not fasten down boards with screws and hardie or similar over the top?
Or its take up ,put 40mm insulation and 50/60mm screed

 

[CJ]

Re: flaoting floor for limestone

Just turned away a job with T&G chipboard & 50mm insulation........floor was bouncing all over the place.

75m job it was as well..........although the floater area was about 20-22m. Couldn't overboard, as they wanted the same level all thorough.......even though I said "no thanks"........they have someone else to do it........love to be that "fly on the wall"

Unless the floor can be taken up and a concrete screed go down......walk away.

 

[Chalker]

Re: flaoting floor for limestone

Fermacell 25mm board on top as a floating floor would decouple. http://www.fermacell.co.uk/en/docs/Flooring_brochure_s_1109.pdf
weight would hold the existing floor still Or take up the chipboard md replace with fermacell boarding. Or visqueen over the existing insulation and 50mm screed over. All options would need edge insulation.

 

[Spud]

Re: flaoting floor for limestone

I had a similar enquiry today Jonny , I don't tile directly over floating floors so The floor is going to have to be removed and screeded it is under 20 m2 so,shouldn't be too much work involved

 

[On one]

Re: flaoting floor for limestone

Fermacell 25mm board on top as a floating floor would decouple. Broken Link Removed the weight would hold the existing floor still Or take up the chipboard md replace with fermacell boarding. Or visqueen over the existing insulation and 50mm screed over. All options would need edge insulation.

Hi Chalker, your link isn't working for me.

 

[Chalker]

Re: flaoting floor for limestone

Hi Chalker, your link isn't working for me.

Works now.

 

[lmkitchens]

Cant you fix the chipboard down to the subfloor with 150mm concrete fixings?

 

[jonnyc]

What about getting builder to take up existing insulation and chipboard.
i could then fix 50mm marmox or similar with flex adhesive to primed concrete base .
of course cocrete would need to be level to just stick down marmox with a notch.
what do you think

 

[Concrete guy]

What about getting builder to take up existing insulation and chipboard.
i could then fix 50mm marmox or similar with flex adhesive to primed concrete base .
of course cocrete would need to be level to just stick down marmox with a notch.
what do you think

I'd be concerned with localised compresive strength with Marmox Jonny. Limestone is so unforgiving.

You've got enough height to get 25mm to 30mm of insulation in then a fibre reinforced screed on top of that.

 

[julian2000]

I'd be concerned with localised compresive strength with Marmox Jonny. Limestone is so unforgiving.

You've got enough height to get 25mm to 30mm of insulation in then a fibre reinforced screed on top of that.

... and Marmox DOES deflect... the oft quoted load bearing capability is distributed and with 10% deflection ... those two words do not sit well with stone (or my mind, very easy to get local high loads). Spike roller every time to get the air out of the SLC as it does make a difference to strength.

 

[Rossymcg]

Ive took up all floating floor in the past then fixed 2x2 timbers in to the block and beam/concrete floor, with the self tapping concrete fixings then fit insulation back inbetween timbers, all of the above I fit on top of a damp proof membrane, 18mm wbp ply with a cement board on top of that,

 

[AliGage]

Remove chipboard.
Lay two skins of 18mm ply, cross fixed.
Concrete fixers right through to concrete base.
SLC and de-couple.

 

[Chalker]

Remove chipboard.
Lay two skins of 18mm ply, cross fixed.
Concrete fixers right through to concrete base.
SLC and de-couple.

Good idea, bit really needs insulation.

 

[AliGage]

Keep the current insulation