Preparation Laid Insulation Boards Without Adhesive - Tile Advice

[Stooboy]

Hi Folks

After a bit of advice please. I am DIY installing elec UFH and tiles into my kitchen before the new kitchen is fitted. The floor is a concrete slab which I surfaced with a layer of flexible self levelling compound. Then laid 6mm polystyrene insulation boards onto which I laid the UFH mat and then another layer of the compound over the top. All went very well and I was pleased. Came down the next morning and 3 small areas had raised a fair bit forming a hump with a void underneath. The screed is so flexible that there were no cracks. 95% of the floor was nice and flat still. Now then, I now know that I stupidly stuck the 6mm boards down with spray glue (aerosol) thinking they just needed to stay in place during installation. I very carefully cut round the areas of matting where the lot had lifted, pulled it up and put adhesive under the affected boards and stuck back down flat, and re-covered with the compound. So the finished product is now flat and level. My fear is if I tile it and fit the kitchen, when the UFH gets turned on come the Autumn will the tiles lift and crack because the insulation boards are not stuck down? Or will the tiles hold it all in place? Tiles are 600x400. Am I worrying about nothing or am I right to worry and rip the lot out and start again?

Thanks in advance for and advice.

 

[Andy Allen]

Wouldn't be tiling anything until I was confident the boards were well and truly stuck to the floor ..

 

[Stooboy]

Wouldn't be tiling anything until I was confident the boards were well and truly stuck to the floor ..

Thanks for the quick reply Andy. I feard as much. The spray glue was rubbish so for the purposes of this thread we can assume that 95% of the boards are not stuck down at all! So I guess it's all got to come up and in the bin! Oh god!!

 

[Andy Allen]

Sorry mate.....I know it's not what you want to hear but at least you've caught the problem now..

 

[Stooboy]

Sorry mate.....I know it's not what you want to hear but at least you've caught the problem now..

Agreed. I would hate for the new kitchen to go in and tiles to start lifting a few months down the line. Lesson learnt!!

 

[Flintstone]

The only way to solve it is all up and start a fresh. At least you haven't wasted any tiles.

 

[J Sid]

yes, will all have to come up, depending what the insulation boards are will determine the best way to proceed

 

[On one]

Sounds like it will all have to come up.
Do you mean polystyrene or polyurethane boards?

 

[Stooboy]

Sounds like it will all have to come up.
Do you mean polystyrene or polyurethane boards?

I think it's Ekoboard? Says Thermopanel on the box! After the advice above I pulled it all up this evening! As you can imagine it was easy! Just pulled it up in huge panel size chunks!

I have MAPEI keraquick S1 rapid set flexible adhesive for the tiles. Can I use this to stick the insulation boards down?

And I'm using MAPEI Ultrplan renevation screed 3240 fibre reinforced self levelling compound to screed over the UFH mat. I'm I ok with this?

Cheers for your help guys!

 

[CJ]

Also, once the UFH gets switched on and up to heat, the spray adhesive will probably soften and affect the lot.

Rip up, and start again.

 

[Old Mod]

I think it's Ekoboard? Says Thermopanel on the box! After the advice above I pulled it all up this evening! As you can imagine it was easy! Just pulled it up in huge panel size chunks!

I have MAPEI keraquick S1 rapid set flexible adhesive for the tiles. Can I use this to stick the insulation boards down?

And I'm using MAPEI Ultrplan renevation screed 3240 fibre reinforced self levelling compound to screed over the UFH mat. I'm I ok with this?

Cheers for your help guys!

Yes that's fine.
Floor Insulation for underfloor heating - EkoBOARD - uses & applications