Tiling on conc. underfloor heating floor before heating is turned on

[patrickoconnell]

I have recently built my house and using underfloor heating covered by a 65mm concrete screed. the floor screed has been laid about 1 year ago. the windows and roof have been in for the last 6 months so it has been drying out since than. The underfloor heating has not been switched on yet but I have tiled the floor using flexi adhesive. I am now wondering will I have a problem when I eventually turn on the under floor heating? Will it crack the tiles?? Any advice will be greatly appreciated.

 

[patrickoconnell]

I have not used decoupling membrane just tiled striaght onto the concrete floor with flexi adhesive. If the underfloor heating is turn on and gradually the temperture is increased will that stop the ant damage that may be caused?

 

[diamondtiling]

The tiles are fixed to the substrate so they will now move with the floor if there is any expansion and contraction issues. You are just going to have to chance it and turn the heating on at the lowest setting and building it up over a long period of time. Alan (Ajax) will be along shortly who is a screed expert, he may be able to best advise you.

Good luck.

 

[patrickoconnell]

Thanks for the advice diamondtiling

 

[Gazzer]

There is nothing more you can do now the tiles are fixed anyway. So as stated start the heating up at the lowest and increase slowly by no more than 5 degrees a day. You say the heating has not been used ? At all ? Was it not commisioned before tiling ?
What tiles have you used ?

 

[diamondtiling]

Just to add to Neale's answer I would suggest an increase of 1 degree per day or even two days just to be extra cautious.

 

[doug boardley]

as above, easy to say now that heating should have been commissioned prior to tiling, just gonna have to suck it and see I'm afraid.

 

[patrickoconnell]

Thanks for ye're advice...I will just have to increase the heat slowly....I dont know if it will make any differance but the tiles arent grouted yet...

 

[diamondtiling]

It might make a difference Pat, I would leave the grouting for now, at least if it all fails you would have saved a bit of money on grout............

Asda price, every bit helps.

:8:

 

[Gazzer]

Just dont forget that when you come to grout the heating must have be off for 2 days .

 

[patrickoconnell]

thanks for the advice....Hopefully it wont wreck all the tiles....

 

[DHTiling]

If the screed shrinks or curls whilst the heating is turned on ,then there is a very strong chance it will debond some tiles and could even transfer cracks to surface.

A screed is supposed to be commissioned before the tile installation and this allows for shrinkage and expansion to take place, An uncoupling membrane would probs have coped with any stress issues if heated slowly but straight onto the substrate, then you have to heat very very slowly and cross your fingers..

 

[Ajax123]

the issues you might have seem to have been covered already. you should NEVER tile a heated screed unless the heating has been comissioned and run. Let's hope you are lucky on this one.

 

[White Room]

You don't mention what tiles were laid