Tiling concrete floor and UF heating

[Boggs]

6. THE SLC has been drying for 3 days and still not 100% dry but hard in most places and still drying - I am told that due to the large area and cold weather this could take a bit longer

3 days?!

How thick was it?
Is it open to the elements?

I would think it should dry overnight.

 

[The Tiler]

was the underside of the XPS boards primed?
used to have to prime all faces of the blue XPS boards and let it dry before fixing

 

[Steve01]

hi yes it was open to the elements for 2 nights as there was a door partly boarded and letting cold air in - also it was 10mm thick as it was quite an uneven floor

 

[Simon Dale]

hi yes it was open to the elements for 2 nights as there was a door partly boarded and letting cold air in - also it was 10mm thick as it was quite an uneven floor

You can put 50mm down in one hit and it will dry by next day or even the same most SLC is rapid. Think to much water used.

 

[Boggs]

The last slc I used was fast track and we were walking in it within the hour.

 

[Boggs]

Was a spiked roller used to remove the air and help spread it evenly?

How big are the hollow areas, are they small localised bits or larger?

 

[Waluigi]

Only thing that would worry me is the lack of SLC before the boards went down. Trying to achieve a solid bed under the foam board when you’re also dealing with adhesive might be the issue.

Yes, potentially too much water in the mix. It’s very difficult to guess the amount of Water needed which is why the amount is specified on the bags.

 

[Steve01]

Thanks for the replies

The hollow areas are local and in patches - when I stand on them and bounce up and down with my heel I can feel the XPS board slightly move and hit the concrete subfloor like a couple of mm but the XPs board heating mat and Slc are all firmly stuck together which I guess is a good sign

My builder watched them do it and he said they primed the floor and then put a thick level of adhesive under the XPs boards using a trowel and stuck them down he said when they were doing the slc it looked a little watery but thought it was ok

They put primer again before putting down the slc

The rest is all dry now and I can walk on it

The only doubt I have is the hollow areas under the XPS boards and when I step on those bits I can feel the floor a little movement and in a couple of cases when I push up and down I can hear air being squeezed out

So the question is do I ask they rip up the hollow areas and probably damage the mat or do I just get tiler to proceed and let the tiles settle the floor down which I assume with the weight will push out any air pockets anyway

He says it’s fine but then he would - I assume worst case I lay the tiles and after time there is movement and then I pull up the affected tiles and fix if and when that happens

Out of interest if anything goes wrong is this type of stuff covered under home insurance ?

 

[Steve01]

was the underside of the XPS boards primed?
used to have to prime all faces of the blue XPS boards and let it dry before fixing

Only the subfloor was primed and then top of the XPs - as you say this may be part of the problem

 

[Dumbo]

its going wrong . You should of followed Harry's @hmtiling advice which you agreed was the right approach . Reading your original post it sounds like you were trying to cut corners and maybe you persuaded the tiler to do it this way or if the tiler said that was how he was going to do it you should of told him otherwise . You did your research and ignored it . You know what needs to be done in your heart . As regards insurance why will they cover shoddy workmanship .