Problems with UHF

[Oliver3]

Hi all,
I am new to this site and wondered if I could get some advice.
I've been a tiler for a few yrs but my knowledge and experiance with under floor heating is fairly limited. I have tiled over UHF using the latex screed with good results.
I got asked to do a quote for a customer who has had a limestone kitchen floor tiled over the electric UHF. The corners of the tiles have cracked and broken. so obviousley the tiler (cowboy) used the dob an dab method! The floor was not screed and here lies the question, I noticed the wiring had been laid on something that resembles compacted polystyrene. Is this acceptable? if I was trying to rectify the problem, by replacing the broken tiles, can I tile over this stuff using flexible adhesive? (that is of course, I can get the wires out of the old adhesive!)

I would appreciate any advice given.
Many thanks,
Tony

 

[Dan]

Welcome to tilersforums.com | Tile Forums | Tiling Forum!

Hi Oliver3 and welcome to tilersforums.com!

 

[Daz]

Any chance of any pics Tony?

The polystyrene boards are the insulation boards, which should hopefully be secured to the substrate (screed?). Normally, there would be a latex slc over the wires but some tilers will cover the wires with adhesive.

Are you sure that the tiles have been D&D'd and have not just cracked because there hasn't been a decoupling membrane used?

Pics will help us diagnose the possible issues, so that we can give you the best advice.

BTW welcome to tilersforums.com.

 

[DHTiling]

Hello tony and welcome..

Without actually seeing what you can it is hard to advise... but it is possible to replace tiles over UFH with great care.. but if damage did occur then these mats can be repaired.

As for the insulation.. what colour is it..?

 

[White Room]

Hi and welcome

 

[Dan]

Both marmox style (with the cement backing) and the type without will probably be blue in colour, either are fine for solid floors, and with either, when pulling up a tile, you will probably see the blue stuff.

It's the fixing method here I assume without more info or pics.

You can use a flexible single-part over either, though a latex or acrylic based 2-part adhesive can only be used on the type with the cement backing on the insulation. Reason for that is the chemicals in the polymers can 'scorch' it or effectively burn it.

 

[Oliver3]

Hi,
Thanks for the welcome, and for the advice.
No pic's at the mo but I'm going back in the morning to have a closer look. Regarding the dob n dab, I can see that has been done as there is no threshold cover and can see the gaps under the tiles!
Not going to do anything drastic tommorrow but may try and lift one the tiles that has broken.
May try and get some pic's on here 2moz.
Again, many thanks for the advice.

 

[suave]

:welcome:

 

[The Legend; Phil Hobson RIP]

:welcome: