Floor tile problems

[Jaggus]

Hi all,

We've had an extension built with 600mm x 600mm floor tiles laid through from the hall into the extension.

In the hall, the tiles are laid on a suspended wooden floor with underfloor heating between the joists, chipboard across the joists and Ditra matting. However, the tiles have come loose and, upon lifting them, the tiler has found that the adhesive is generally not stuck to the underside of the tile. The floor is a little bouncy, but we've been told the Ditra matting should have been fine for this.

In the extension, the floor was concrete block and beam with underfloor heating and a concrete screed. In here, the tiles have also started to come loose. In here, though, the adhesive is stuck to the tiles, not the screed. The tiler has already lifted and re-laid all the kitchen tiles and the same has happened again.

The builder has said the tiler is unwilling to re-lift and lay all the tiles again until they know the cause, but they cannot find anyone who can help. They have taken samples of the adhesive and screed but cannot find a company to analyse them.

Meanwhile, we're left with a loose floor in our newly built extension and hall.

Does anyone have any ideas? Would there be companies that would take on the problem?

Please let me know if you have any questions or need any more info?

Thanks in advance!

Paul

 

[Mr Chibs]

Sweet Jesus. Not what you want.

I’ve not long complete my floor/tiling and is similar. I’m using same matting.

Did you have liquid screed (pumped) or sand and cement put down manually?



Liquid screeds need the laitance removing off the top of the screed once cured, (Chalky bit) then a priming with latex, 3 coats... then you can stick the decoupling mat down. Then tile.

I questioned this need for primer and was told liquid screeds don’t take well to cement type adhesives.

 

[Jaggus]

Hi Mr Chibs! Thanks for your reply.

It was a liquid screed that went down over the extension floor. It was a quick-drying one - the slow drying one was going to take weeks to dry and we had a kitchen scheduled for delivery. I didn't monitor the work too closely (I'm an bumbling DIY-er myself so this is way out of my league!!) but I think the tiler primed the floor over the screed and then put the tiles down with the adhesive. When he came back to re-lay the floor, he took the tiles up, ground the adhesive off the underside of them all and then ground the screed to provide a key. He then re-primed it, and re-laid the tiles. I assume the decoupling mat is what I call the Ditra matting? If so, there is none of that in the extension. I don't think they felt it was needed as it was on screed and there would be no movement?

It sounds like he should have removed the laitance off the top of the screed first time (I didn't see that being done), primed with 3 coats of latex (didn't see that either) and then put down decoupling matt (that isn't down) before tiling.

Any thoughts on the hall, which does have the matting?

Many thanks!

 

[Swwils]

What a pickle.

What exact products were used? Was it actual ditra-25? Please list all, inc. the screed, adhesives and tiles.

Are any tiles still up? Please take some photos of the substrate and the backside of the tile.

Seek the advice of another professional tiler.

 

[Jaggus]

Hi,

I spoke with the builder and he has confirmed the steps they went through were :

1. Block and beam floor put down
2. UFH heating pipework installed
3. Anhydrite quick-drying screed poured – allowed to dry
4. Scraped off and brushed off the laitance
5. Primed the surface with BAL APD primer
6. Applied Ultra Tile Fix Pro Flex SP adhesive
7. Installed tiles and grouted when dry
8. Tiles came back up, lifted tiles, adhesive stuck to the tiles
9. Scraped underside of tiles
10. Grind screed with diamond blade to make sure going deeper
11. Primed the surface with BAL APD primer
12. Applied Ultra Tile Fix Pro Flex SP adhesive
13. Installed tiles and grouted when dry
14. Tiles came back up, lifted tiles, adhesive still stuck to the tiles

The Ditra matting was not used in the extension (only in the hall, but I will find out the spec), the adhesives are detailed above, and the tiles are Crema Marfill Lucidato porcelain tiles 600x600x10mm thick (87 sq.m. of them).

I've uploaded some photos :

- The first shows the kitchen floor where the tiler has been scraped away some of the screed to take a sample (which he is trying to get analysed, but unsuccessfully at the moment)
- the second shows the hall floor. You can see the yellow Ditra matting that was used in the hall.
- the third shows to the underside of a tile from the kitchen floor with all the adhesive still stuck to it.

 

[Mr Chibs]

How long was the screed left to dry?

How long from tile completion did you turn the ufh on?

Yes that is Ditra decoupling mat.
It should be used when ufh is installed, are you sure your floor doesn’t have this?


Also I think a larger notched trowel should be used for larger tiles. (I’m sure the real tilers might put me straight, so I might stand corrected.)

Keep us posted.

 

[Jaggus]

Hi Mr Chibs,

Just to add to my previous post, the Ditra matting (in the hall only) was Durabase CI matting.

How long was the screed left to dry?
The screed in the extension was put down on Friday 13 Mar 2020 and allowed to dry for 2 weeks. However, I don't think the floor tiling started to go down until 08 Apr 2020.

How long from tile completion did you turn the ufh on?
I don't remember how long we waited until the UFH went on, but I remember it being off at the time. There is UFH throughout the hall and the extension

Yes that is Ditra decoupling mat.
It should be used when ufh is installed, are you sure your floor doesn’t have this?
There is definitely no Ditra matting in the extension - it is in the hall only. This was put down as the floor is suspended timber and it was felt this was needed to cater for the movement in the timber floor. It wasn't felt to be needed in the extension as this is block and beam.

thanks,

Paul

 

[Mr Chibs]

Mine is on a solid concrete floor, and I was advised to use it... being honest I pulled a face as I hadn’t realised the extra cost.

The screed may move when it’s heated, then cools then heats etc.
That said a lot of people won’t use it on a solid floor and presumably have no problems.

Has the mat stayed stuck to the wood floor?

Is there any chance too much water was added to the adhesive?

Sorry I don’t think I’ve any other suggestions.


Chibs

 

[Mr Chibs]

Just looked at the picture again with the mat... looks like two layers of adhesive... unless it’s my eyes.

Large notched layer, then the top layer is fine notched trowel... if correct was the original adhesive not removed?

 

[Jaggus]

Hi Mr Chibs,

Thanks for your thoughts. It has provoked some thoughts on my side.

In reply to your points :

Mine is on a solid concrete floor, and I was advised to use it... being honest I pulled a face as I hadn’t realised the extra cost.
I thought my floor (in the extension) was solid concrete too, but you can feel movement when someone jumps on the floor. The concrete beams do flex slightly.

The screed may move when it’s heated, then cools then heats etc.
Agreed, although we tend to have the thermostat set at a constant 19 degs as it holds the heat and takes ages to warm up. It's a nice feeling underfoot.

That said a lot of people won’t use it on a solid floor and presumably have no problems.
You'd hope that this is a one-off. Both my builder, and his tiler, are scratching their heads. I had the idea of asking this forum.

Has the mat stayed stuck to the wood floor?
Yes, but those tiles have lifted off the adhesive leaving the underside of the tile clean.

Is there any chance too much water was added to the adhesive?
Its possible, but I wouldn't know. The tiler is an experienced guy so I'd expect him to have got that right...

Sorry I don’t think I’ve any other suggestions.
That's great, thanks for your help. We're running out of ideas too. One suggestion was asking another tiler. I don't know one and, of course, my builder only has his one, but I will ask the company that supplied the tiles if they can recommend someone. I'm also thinking about contacting my home insurance company to ask their advice. It's not dangerous, but not what we want to live with for any longer than necessary.

Just looked at the picture again with the mat... looks like two layers of adhesive... unless it’s my eyes.
Large notched layer, then the top layer is fine notched trowel... if correct was the original adhesive not removed?
The photo with the matt is of the hall with the wooden floor. I think what you're seeing is adhesive spread on the floor, and another layer of adhesive spread on the underside of the tiles. The two layers of adhesive have bonded, but the tile has not bonded.

Cheers,
Paul