Hairline craks in SLC

[vrytir]

Hi guys,

I came with another problem. I use mapei Ultraplan renovation screed to self level my floor with cable UFH. And now I found hairline cracks in it. Does it mean my subfloor was not good enought and I can start again or is it normal.
Subfloor is WBP 18mm, mapei ultraflex, 6mm insulation board, then the UFH cables and now screed. I put quite a lot of noggins when installing WBP.

For the floor it will be ceramic tiles 300x300, using mapei ultraflex as adhesive. Not sure about grout, is there some "flexible grout"?
Or do I have to start again from scratch?

What is you opinions, please?

 

[DHTiling]

How thick did you use it and did you prime.. ?

 

[vrytir]

I prime it with Primer G and it is about 10mm-12mm thick. This ultraplan screed could be up to 30mm thick.

 

[DHTiling]

Ok, how much water did you add. ?

And is there any deflection in the substrate..?

 

[vrytir]

It was 4.5l per 25kg bag and deflection? Well I am big guy 20st roughly and when I put my laser leveller on the WBP there was some movement, but when my better half did the same there was just slight move.

 

[DHTiling]

I think that could be the issue.

How soon did you walk on the floor after levelling.

 

[vrytir]

I left it about 24 hours to dry. Mapei recommend 4-5 hours.

 

[charlie1]

Think mapei recommend using eco prime, unsure if this would be a factor in what's happened though

 

[Ajax123]

Could just be drying shrinkage. Pictures might help

 

[vrytir]

Could just be drying shrinkage. Pictures might help

I hope :smilewinkgrin:

I try to get pictures tomorrow.