Bathroom tiles lifted

[jobirdster]

Hi;

I am a homeowner who recently had an extension built with a ensuite, we bought Pro warm electric underfloor heating kit and a 600 x 600 tile for the floor

We had them installed pre Christmas and this last week the middle section of the tiles have all lifted / peaked up and cracked. 4 tiles right in the middle of the bathroom are affected but all the other tiles now sound hollow too when we tap them.

The method for install was a thermal board, electric matt, screed and primer which came with the pro warm mat.
The tiler insists he has used a good quality adhesive Ultra Flexible
We did not turn the electric mat on for at least 6 weeks after install.
When I look at the back of the lifted tiles they are clean, no adhesive on them... adhesive seems to have stayed on the screed.

My questions.
Do we need expansion gaps on this size of floor with electric underfloor heating ? size is no larger that 3m x 3m tiles are 600mm x 600mm porcelain matt and are sold as suitable for underfloor

I have had another tiler out and he states that its either substandard adhesive, not being primed properly or no back buttering of the tiles.

The tiler who fitted them said he never back butters, the primer he used was supplied from the underfloor heating kit and the adhesive he used was Ultra Flexible.

Can anyone shed any light on what could have happened please ?

I need to find a solution/ idea of whats gone wrong so I can get the tiler to correct it.

 

[eddcottee]

No membrane is needed with those tiles, thin porcelain and stone, yes.
Bad fixing technique, a membrane would not have helped in this situation Edd

Thanks Julian

 

[jobirdster]

Thanks to you all. You have mentioned exactly what the tiler who came to look at it said.

Just so I know, for an expansion gap what does it consist of ? Is the gap filled with Silicon or with tile grout ?

 

[widler]

Is there skirting on, is it tiled up to wall tiles , a couple mm gap then Silicon or gap than no Silicon then skirts

Post automatically merged: Feb 20, 2020

Just seen its tiled up to tile, so Silicon .
I know every customer says it gradually turned the heating on, but hand in hete , did u wack it in full pelt straight away ?

Post automatically merged: Feb 20, 2020

‘Hand on heart’

 

[J Sid]

Thanks to you all. You have mentioned exactly what the tiler who came to look at it said.

Just so I know, for an expansion gap what does it consist of ? Is the gap filled with Silicon or with tile grout ?

5mm gap round room, clean of adhesive and grout then silicon this gap

 

[jobirdster]

Is there skirting on, is it tiled up to wall tiles , a couple mm gap then Silicon or gap than no Silicon then skirts

Post automatically merged: Feb 20, 2020

Just seen its tiled up to tile, so Silicon .
I know every customer says it gradually turned the heating on, but hand in hete , did u wack it in full pelt straight away ?

Post automatically merged: Feb 20, 2020

‘Hand on heart’

There is wall tiles on most of the walls, just two areas with a small tile skirt. Rest butt up to wall tiles.

We didn't have the electrics connected for at least 6 weeks, (might have been even longer) after the tiles were laid. We waited ages for the sparky to come back.

Hubby turned on and is sure he put it on 16 degrees at start and then up to 20 .

 

[Smiler5714]

Defo expansion gap needed but also with any underfloor heating you need a solid bed of adhesive. One reason for needing a solid bed is for thermal transfer of heat up from the mat and through into the tile. Air is a very poor conductor of heat and so if you have air trapped between trowel ridges you have a very uneconomical system. Secondly, if the air pockets are quite large you can also have a problem where the heated air expands and again, it could possibly cause lifting of the tiles, especially if they weren't very well bedded to start with.

When solid bedding it's always better to butter the back of the tile.

 

[al strachan]

ignore

 

[Etherglide]

The trowel marks look like !0mm at the most. I suspect not back buttered. Oh, and the heating was turned on too quick. Dismiss an expansion joint at the walls. Most of us, if were being honest, don't tile tight to the wall anyway.

 

[jobirdster]

The trowel marks look like !0mm at the most. I suspect not back buttered. Oh, and the heating was turned on too quick. Dismiss an expansion joint at the walls. Most of us, if were being honest, don't tile tight to the wall anyway.

It took us over 6weeks to have the electrics for the UFH connected. We were advised 2 weeks was enough but we didn't have a sparky on site for ages.

 

[J Sid]

It took us over 6weeks to have the electrics for the UFH connected. We were advised 2 weeks was enough but we didn't have a sparky on site for ages.

Its the turning on and how the heat is ramped up slowly over the next week which is very important after the tiles and adhesive has set.
Turning the ufh on and taking it high straight away could give thermal shock leading to floor failure, looking like your floor looks now