New concrete floor

[trevorbayliss]

My mate has had a new pumped concete screed laid in his whole ground floor. They have UFH.

He let the place dry out for 11 days and then slowly introduced heat.

He has had quite a bit of cracking especially around the doors.

He is planning on laying a new very thin cement screed and laying some mesh product into it.

I said this was a bit OTT and thought i would ask opinions on here what he should do.

I was wondering if the BAL stopgap product would be all he needs to lay down:
http://www.directflooringcentre.co....utM9DYuGi1WpW0PuDU1G7H374gLi7FFBoCV1UQAvD_BwE

Advise appreciated

 

[KenGMac]

trevorbayliss, good evening.

As I recall, with a large area of concrete, it was at one time advised to introduce expansion / contraction joints in certain places.

1/. Fit a flexible joint between concrete slab and walls there are various proprietary materials.

2/. At the doors? introduce a crack inducing strip, dead center over the width of the opening.

The cracking has probably happened because the rooms are different areas, which shrink at differing rates hence the cracks in the Concrete at the doors?

As for a thin screed, must admit I am not a fan? sorry about that

Do you know if your mate used the UFH to introduce the heat? and what thickness is the Concrete slab??

Ken.

 

[trevorbayliss]

Yes he used the ufh to put the heat into the slab. The area doesn't need expansion joints apparently as this pumped screed can be laid up to a certain amount without them. His ground floor area was under this amount. Not sure of the thickness

 

[rssteve]

He should lay the tiles on ditra.

 

[trevorbayliss]

This is the stuff he is using, but for the whole area downstairs. It seems over kill to me. I mean it must be 50-60 sqm.

I thought there must be a cheaper and easier way to solve the cracks.

 

[rssteve]

The ditra should stop any further cracking of the slab causing problems. Like when the underfloor heating is turned on or off.