Tiling concrete floor and UF heating

[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 .

 

[Boggs]

You were advised how to approach this and have ignored it and it’s failed.

Cost cutting is to blame I believe....

 

[Steve01]

All of Harry’s advice was followed and I went through it with the tiler and insisted they do this despite them suggesting skipping some steps

I can assure you no corners being cut

Before the job started the builder was going to put down SLC which would have cost me £250 more and I already paid the builder to buy materials - but the tiler came and said the concrete floor was fine and he could prime the floor and lay the boards and self level after - I asked him to wait a day for the builder to self level but he insisted with his 20 years experience it was fine as is and maybe he was right

The step that was missed was the slc on the concrete floor at the insistence of the tiler

So please don’t blame my cost cutting as I actually went for one of the higher quotes and have specified all of the premium materials with no expense spared - for me quality is paramount !

I blame shoddy tradesmen claiming they know how to do the work but don’t and me having to do my research in advance due to the inconsistent and differing approaches offered by apparent ‘professionally qualified’ tradesmen

Anyway I have one of the other Tiler’s who initially quoted me to give another opinion and then will decide what to do

As it stands there are a few spots like this which as I said are isolated and with the tiles laid should resolve the problem so will see what the other Tiler says and decide what to do

I am probably being overly cautious and I am sure that this is Absolutely fine - was looking for some similar stories or experiences but fine if there aren’t and i can understand it’s hard to give advice without seeing it

On a separate note I did speak to a friends tiler who is very good and hence booked out for 6 months which is why I couldn’t use him - he has done a lot of UFH and he said the hollow sounds are normal as the XPs foam type board is very thin and almost hollow- he said this will resolve once the tiles are fitted


Thanks again

 

[The Tiler]

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

never used to be, perhaps they have changed there recommendations

 

[Flintstone]

Steve, forget all the he said she said nonsense. Whatever they have done, movement and the board bouncing is only going to end one way. Wish we had photos of some of this progress.

 

[Waluigi]

The other Tiler suggesting it sounding hollow is fine is right but the board isn’t just hollow sounding, it’s also moving = not fine.

 

[Steve01]

Yes correct over 35sqm I have found approx 8 patches of about 15 cm square each where there is a slight movement due to air in there

I will just ask whoever tiles it to cut these sections out without damaging mat before tiling

The rest of the floor is sound and no point taking the whole lot out

Thanks

 

[Steve01]

Sorry one final question - assume that I should insist the tiler applies primer on SLC before tiling

I know that’s what was advised above but just want to be 100% sure as there seem to be different views on this

 

[One Day]

How to turn a job into a nightmare....!

 

[Dumbo]

You can not say you followed Harry's advice you left out levelling before boarding .
Good luck cutting out 150 mm squares with approx 50 mm wire spacings

 

[Steve01]

You can not say you followed Harry's advice you left out levelling before boarding .
Good luck cutting out 150 mm squares with approx 50 mm wire spacings

Yes as I said I followed the Tiler’s advice who said SLC wasn’t needed - cowboy tiler !

As for cutting if my new tiler is confident they can cut around the wire safely to remove dead spots then great if not will go ahead with tiling as it’s such a small area anyway

Is there any way to drill a small hole and inject some adhesive in the gaps that would be the most sensible answer ? Not sure if anyone has any experience of this ?