Hello everyone

[RayJay]

Hello my name is Ray
I am a Building Surveyor by profession and also a keen DIY er.
I have recently completed an extension on my house an I am at the floor tiling stage. I have tiled floors previously but not of this size and not with wet underfloor heating.
I have been doing some research on the web including this brillant forum but I am still unclear on some issues and would like some advice.
The floor is concrete screed laid May 2011 by a floorscreed firm including reinforcing fibres ,D49 mesh at stress points (corners etc) .The UFH has been in use since November.
The screed does have a couple of hairline cracks. Part of the floor will exposed to sunshine due to 3 velux windows.
The tiles are 600mm x600mm rectified porcilean.
The floor is L shape, 42m2 with a maximum length of 7.4m.
I intend to leave a 10mm gap around the entire perimmeter.

My questions are:
1.Should I use an isolating membrane over the whole floor or just over the cracked areas ?
2.Should I use 2mm or 3mm spacers?
3.If I need an isolating membrane, I will need a thin one such as PCI pecilastic. I can only find 1 online stockist. None of the local merchants seem to stock it.
Does anyone know of any stockist near Croydon?


I would be grateful for any advice. Thanks.

 

[DHTiling]

Hello Ray and welcome..


personally i would use an anti crack mat.... you can get mapietex crack mat... just as thin as pecilastic... if you ring PHG wetrooms , number in the link in my signature, he can supply it to you..

 

[nybor62]

3mm spacers

 

[Stewart]

Membrane/decoupler for me too and I would use a minimum of 3mm on a heated floor though some manufactures are recommending larger grout joints on heated floors.

 

[RayJay]

Thanks for the reply. It looks like a membrane and 3mm joints is the answer.

I do have another question though. I have checked the screed with a rotating laser level and it appears to be pretty level (within 3mm), will a 10mm bed be sufficent for the tiles? Also what is the differerence uses/ preferences betweem square notched and U notched trowels?
Sorry thats 2 questions :smilewinkgrin:.
Thanks again.

 

[Rich]

Good advice above regarding membrane and 3mm spacers (min). You need to get your self a U-notched trowel (or half moon trowel), the square notched trowels are not as good at getting 100% coverage of adhesive under the tile. Spread a good bed of adhesive onto the floor using the half moon trowel (leaving no gaps and try to keep all the notches going in the same direction) and then you will want to back butter the underside of the tile with adhesive as well. Then when you press/twist the back buttered tile into the adhesive bed, this should give you 100% coverage.

 

[Rich]

Oh and welcome to the forum :hurray:

 

[swanman]

Good luck and were knee pads

 

[White Room]

Hi and welcome...

 

[Ian]

Welcome along to TF

 

[RayJay]

Thanks again for the replies and the welcome.

I have ordered the membrane and other materials which should arrive tommorow.
I'll let you all know how I get on :incazzato:.

 

[The Legend; Phil Hobson RIP]

Hi Ray, and welcome to TF.