Discuss Prowarm tiling advise please in the Tiling over Electric Underfloor Heating area at TilersForums.com



Hi guys and gals.

This might be in the wrong forum area so I do apologise. It’s also my first post so please be gentle.

I need some advice on advised installation steps for UFH. So I’m currently having a large dining, kitchen, living area renovated. We have an electrician install Prowarm matts. They are not let laid, and this is where my issue arises.

The system is being fitted on a concrete subfloor and we have limited space between the floor and the bi fold doors that have been fitted. It should all fit but the adhesives might push us over.

The proposed set up should be as followed, (as it would be laid)

4) Porceline tile.
Flex adhesive
3) Ditra Matting.
Flex adhesive
2) Prowarm Matting
Flex adhesive
1) Insulation board.
Flex adhesive
Concrete subfloor.

From looking at the guides online it’s suggested Flex adhesive is needed between each layer.

The question is then, is this actually needed ?

We have roughly 70 square metres to cover, so
A) the cost is gonna add up massively with 4 layers of adhesive
B) that amount of laying will potentially raise us 10mm - 12mm higher than anticipated.

Is there a way to avoid this, ie is there any layers of adhesive we can avoid? Or is it unavoidable.


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  • Thread Starter Thread Starter
  • #2
Welcome. Your method is incorrect. It should be-

4) Porcelain tile
Flex adhesive
3) Ditra Matting - (not essential, but personally I always recommend it if it can be afforded)
Flexible self levelling compound

2) Prowarm Matting (stuck to insulation board)
1) Insulation board
Flex adhesive (seeing you're using it in rest of job)
Primer (Acrylic or SBR)

Concrete subfloor

You WILL need expansion joints in all doorways and at a point where roughly 40sqm ends, I would personally put it around 35sqm point.

What shape is the room?

Are you doing this yourself?


  • Thread Starter Thread Starter
  • #3
Hi Plan Tec.

Thanks for the reply. And appreciate the advice. I’ve just been trying to figure out method off the internet.

The room is rectangular. Each room was 5x5. We’ve taken the walls out so the room is now 15x5. Format Kitchen - Dining - living room.

And yes Myself and my mate who’s a builder is doing the work.



  • Thread Starter Thread Starter
  • #4
Expansion joints required at changes in screed/ floor construction too. Is it one whole new screed or a new screed in one area only. A diagram or photos will assist.

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  • Thread Starter Thread Starter
  • #5
So where the walls were removed the floor had been levelled. But just in these areas.

We are limited with what we can do as the bottom frame on the bi fold sits only 25mm above the subfloor

Matting 3mm
Insulation 6mm
Ditra Matting 3mm
Porceline tile 10mm
It really is a tight fit and the doors cannot be changed.

I do understand the UFH won’t go the edges but I’m presuming the ditra will go tight to the edges, as does the insulation.

Everything for the build is purchased. It’s just a case of getting our heads around the install.


  • Thread Starter Thread Starter
  • #6
Ditra heat duo could have saved you a couple of layers and quite a bit of height but it's a bit late now you've bought materials.


  • Thread Starter Thread Starter
  • #7
Or dont use the ditra. Will save some height. I would self level over the cables though.
Expansion joints will most likely be needed where wall was.


  • Thread Starter Thread Starter
  • #8

Yes unfortunately we didn’t do our research fully, and got the Matting and insulation first. Had that wired and all the walls plastered etc. Then was told by the tile company we should 100% have Ditra Matting and then realised the multiple lays of adhesive was needed.

If I knew all this, I’d have probable stuck with radiators but what’s done is done.

So essentially we NEED adhesives between each item. There isn’t any avoiding this?

Deleted member 38091

Sep 7, 2012
4,662 58 1
What member type are you?
Professional Wall and Floor Tiler
Ditra matting if applied properly using adhesive and a 4mm trowel will bed down to nothing .

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