cracked!

[stevegreen]

Hi, hope someone can help, I have tiled three quarters of my kitchen floor which has wet underfloor heating and sand and cement screed. The room size is approx 8m x 5m and has an expansion joint splitting the screed into two bays. I have been using mapei makeper tiling adhesive. Prior to plastering the room I covered the whole area with cardboard to protect the screed, and have been uncovering as I go. My problem is - when uncovering the last area to be tiled, I have found a crack in the screed which goes across the width of the room (but not in a straight line) the width of the crack at most is only 0.5mm wide.
I can't use an isolating matting in this area as i won't be able to maintain the correct levels. Has anybody got any suggestions about tiling over this area that would help in preventing the crack affecting the new tiles.
Thanks.

 

[nybor62]

how long as the screed be down for and how thick is the screed

 

[Gazzer]

Has the heating been commisioned ?

 

[stevegreen]

Screed has been down approx 12 month and is 65mm thick.

 

[shaney2000000]

You can get matting thats only 1-2 mm thick

 

[stevegreen]

Yes the heating system has been commisioned.

 

[stevegreen]

Who makes this, and how much adhesive above and below would I need. Thanks

 

[Rich]

How much height do you have to play with? Most matting is only 3mm thick and you can lay it with a very thin bed of adhesive and then tile over the top of it with a solid bed trowel as you would do normally.

 

[stevegreen]

I've got 6mm max!

 

[Saltire69]

Mapeker is unsuitable for underfloor heating.

 

[Daz]

Mapeker is unsuitable for underfloor heating.

What makes you say that Saltire???

Here's the spec sheet direct from Mapei website that states it is suitable to UFH installations....

http://www.mapei.com/public/GB/products/mapeker rapid-set flex_uk.pdf.PDF

 

[stevegreen]

I don't think i will have enough depth to install matting - would Keraquick mixed with latex plus help?

 

[Ajax123]

Why not resin stich and overlay the crack with a fibre glass mesh scrim to stabilise it.

Here are a some of products you could use

UZIN: Product Search[productsubgroup]=2&tx_ddproductmatrix_pi1[productgroup]=3&tx_ddproductmatrix_pi1[cmd]=search&cHash=df13d483b315bef867be8d03109d9d87

go to Product Overview and Substrate repairs page

 

[Saltire69]

I stand corrected. Didnt think the old Mapeker was flexiable.

 

[chrisroe]

half right they upgraded the spec on mapeker as they found it is flexible but not a fexible as kerraquick