77mm between concrete and existing tile floor - Tile Advice

[j45p41]

Hi,

we've been victim to an AWOL builder who has not left enough space for us to insulate with 50mm pir board, screed and then tile.

I was thinking 50mm PIR board over concerete, chipboard and then no more ply.

Should I self level the concrete, assuming the concrete is level but just bumpy or would the PIR board form a level enough base?

Could I just use no more ply on top or should I use a layer of notched chipboard? Thanks!

 

[Dumbo]

Is that 77mm to underside of existing tile .

 

[J Sid]

Is the 50mm board because of building regards?
Is there damp course membrane under concrete slab?

 

[Dumbo]

As @JulianSidney is there a Dpm,
I would consider liquid dpm that is specific to tiling , so one that can deal with a low build up on top , level over then stick 50 mm insulation boards on top followed by 20mm boards unless you can get 70mm boards .
You may need to check this against building regs to check that the insulation values are up to spec.
If you want to tile don't make a floating floor it will fail .

 

[Tile Fix Direct]

To extend JCR's comments you could lay a liquid damp proof, then stick 50mm Orbry board followed by 20mm Orbry board then tile direct onto the 20mm.

Orbry Waterproof Insulated Tile Backer Board (1220mm x 600mm)

Shop Orbry Tile Backer Boards from Tile Fix. Find Orbry products in our huge range of cement boards and tiling supplies. Free delivery on orders over £375ex.

www.tilefixdirect.com

 

[Ajax123]

Hi,

we've been victim to an AWOL builder who has not left enough space for us to insulate with 50mm pir board, screed and then tile.

I was thinking 50mm PIR board over concerete, chipboard and then no more ply.

Should I self level the concrete, assuming the concrete is level but just bumpy or would the PIR board form a level enough base?

Could I just use no more ply on top or should I use a layer of notched chipboard? Thanks!

Is 50mm pir critical. If you could reduce this to 40mm using a better performing insulation underpaid perhaps with thermofoil you could then put 35mm of Gypsol rapide screed on top.

 

[j45p41]

Is the 50mm board because of building regards?
Is there damp course membrane under concrete slab?

Thank you for your help.

Yes PIR is due to building regs and there is a DPM below concrete but I was going to add another on top before PIR anyway, given that I will be using chipboard.

Is 50mm pir critical. If you could reduce this to 40mm using a better performing insulation underpaid perhaps with thermofoil you could then put 35mm of Gypsol rapide screed on top.

Hi Yes, 50mm is required. We had to haggle and get it reduced from 75mm.

So at the moment i go 5mm over what I need, if only there was a way of getting chipboard that I could lay tiles on directly....

 

[Dumbo]

Thank you for your help.

Yes PIR is due to building regs and there is a DPM below concrete but I was going to add another on top before PIR anyway, given that I will be using chipboard.

Don't use chipboard if you can avoid , you will thank us in the long run , in fact do not under any circumstances make it into a floating chipboard floor if you want to tile it .

 

[j45p41]

Is 50mm pir critical. If you could reduce this to 40mm using a better performing insulation underpaid perhaps with thermofoil you could then put 35mm of Gypsol rapide screed on top.

Here is a possible solution - anybody used DITRA?

	mm
Allowance	70​
PIR Insulation	50​
chipboard	22​
Schluter DITRA Matting	3​
tile depth	5​
Overshoot	-10​

Still got the 10mm overshoot though