Tiling concrete floor and UF heating

[Steve01]

Hi all

I am new to the forums and looking to get my kitchen diner floor tiled which is approx 30sqm

The tiler is proposing following
1. Self level floor as old tiles were taken up and some of the adhesive is still present and not flat floor - Is this needed or can insulation boards just be applied with adhesive which will cover imperfections
2. Apply XPS insulation boards with keraquick adhesive - does he need to prime the concrete subfloor first after self levelling before putting down insulation boards if so which primer ?
3. Lay electric underfloor heating mat on insulation board - again do you just apply the primer that comes with the mat to the insulation boards and electric mat before tiling
4. Use keraquick to fix tiles to mat and insulation board - at this stage is self levelling latex recommended on top of the mat before laying down the tiles ?
5. Grout and polish tiles

Any other advice appreciated to ensure he is doing the right thing - large area and big investment so want to ensure it is right

Thanks

 

[hmtiling]

Prime, slc, prime, thermal boards, prime, ufh, slc, prime and tile. Use a primer same brand as adhesive

 

[Steve01]

Thanks

I am using keraquick do assume I need mapei primer g

Also do I need to self level after putting down ufh as dont have much height to work with or can good layer of adhesive covering cables work ?

 

[Flintstone]

Steve, why are you questioning his methods? Do you have confidence in him and have you checked out his credentials ?

 

[Steve01]

Yes he is qualified but never used him before - just when I am spending £5000 I want to ensure job done properly so like to do my research

 

[Ajax123]

Is this another "wow that's more expensive than I thought" posts. If the tiler has recommended that works be done they probably need doing and in turn paying for. You should be pleased his methods are robust. I would be more concerned if he were asking some of the questions you have asked. Let's say for instance someone here says the floor does not need priming. You tell the tiler, the tiler either walks away or doesn't prime. That becomes your spec and morally your responsibility of it goes wrong. If you don't trust his recommendations don't use him. If you do trust his recommendations don't question them.... grrr! I must be in a bad mood... grrr!

 

[Dumbo]

@Localtiler @Ajax123 i thought that as soon as i read it yesterday .

 

[Flintstone]

I'm a bit confused here steve, your first post is about a tiler and your second is about yourself doing the job...

 

[GoneGuy]

I'm a bit confused here steve, your first post is about a tiler and your second is about yourself doing the job...

Same here?

 

[Steve01]

Hi Thanks for the replies

Firstly I am definitely not doing this myself its too big a project - I have done a smaller area myself before though and did all the research hence wanting to ensure the tiler takes the right approach

When I say 'I' it refers to getting the work done on my property

@Ajax123 the cost does not worry me - I am the one that has insisted we do everything- insulation boards prime at every stage slc etc and so money is not an issue but want the job done properly

I asked 4 quotes from checkatrade which were similar and went with the one that seemed like he would take his time and do a good job

it was interesting to see what different tilers said and hence the confusion also not many tilers were comfortable with the UF heating or had a consistent view on what needed doing

some said SL on top of old tiles. some said no insulation boards needed and some said that don't need to self level on top of the UF heating hence the initial post to all you experienced tilers out there for some help - sorry but I thought that what this forum was for - for tilers but also homeowners like me to ensure we get the right people for the job and some independent QA on what they are doing

Anyway really appreciate the advice and as @hmtiling says the right approach is as he has outlined from what research has told me

so the work has started and the following has been done by the tiler:
1. old tiles taken up - approx 30sqm this left lots of lit bits of glue and tile so it wasn't a perfect surface
2. the floor was primed
3. the tiler was happy to put the 6mm XPS board down on there using the adhesive to level as he went rather than slc first
4. once the board was down he primed on top again using the UF thermal primer - I noticed some of the insulation board not completely stuck down in the evening and so asked him to go over where it was not done properly - yes that did ring alarm bells
5. after that he self levelled using mapei ultra plan - he ran out of that and used another universal SLC (which says it is suitable for UFH according to the package which I ensure I checked ) to top up the non UFH mat areas and some of that was probably used on the mat to finish off as far as I can see
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

As it dries I have been checking over the area with the SLC and some areas seem hollow although not cracking - when I knock with my hand then some areas are solid and some are hollow like there are air pockets under the insulation board where it has not perhaps stuck to the concrete or there was not enough adhesive

is this something to worry about - i.e tiling on top of the hollow areas OR will I need to get those areas smashed up and corrected - no doubt the mat would be damaged and would require almost restarting ?

I did my research and hired someone who seemed to have the right credentials but am now a bit worried - I do pay attention to detail and have been checking work at every stage - its who I am - if I wasn't on site or left him to it I am sure all the tiles would be down now and I wouldn't know any different until perhaps I had issues in future

I am sure I will get lots of advice on the type of tradesmen I should or shouldnt have got but would really appreciate some advice on what to do next primarily the concern is around the hollow sounds on the floor - it is hard and solid to walk on but as I said just hollow in some areas which I don't want to cause issues in future

I will be getting 600 x 600 porcelain tiles fitted

Many thanks in advance for your any advice

 

[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 .

 

[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.