Bathroom Floor tiles coming loose. Advice Please.

[ptoddy26]

Hi guys

Was hoping I could get some help / advice on whats gone wrong.

My bathroom floor is 18mm WBP Ply on top of the floor joists. I put lots of noggins in as well. Once done even with a glass of water on the floor and jumping there was a very slight quiver of the water but you could only just notice it so I think it's sturdy enough.

I had a product called fastheat which came with my UFH (see pic).


WP_000083 by ptoddy26, on Flickr

Wasn't going to use it but thought what the hell I may as well. This went on top of the ply.

I then used Mapei super flexible adhesive (see pic) and Mapei flexible grout.


WP_000082 by ptoddy26, on Flickr

I have some tiles that have come loose so I have taken them up. If i'm very careful I can easily save the UFH so not too bothered about taking them up. The tiles I have taken up shows (I think) that the adhesive has bonded to the tiles but not the floor. I've attached some pics for you to see.


WP_000080 by ptoddy26, on Flickr

The back of the tile seems to have adhesive bonded to the back. But the next pic shows the floor which doesn't seem to have adhesive bonded on it.


WP_000081 by ptoddy26, on Flickr

The pink stuff is the fastheat. Have I made a mistake in using this product? Or is it the webbing in the UFH that has stopped the bonding to the ply? To make sure should i cut the webbing out, sand the fastheat primer off and reapply the adhesive. Or do you guys think it's something completely different?

Thanks in advance for your help.

Paul

 

[lukeb]

To me looks like faulty installation....

 

[macten]

Looks like the mats been installed upside down.

 

[White Room]

I would have self leveled the matt before fixing tiles....

 

[ptoddy26]

Lukeb - Ok could well be. But can you explain why and what I should of done? It's fine telling me it's faulty installation but I need to learn why.

macten - I don't think the mat is upside down as the sticky side of the tape is stuck to the floor. But even if it's upside down the only difference is the sticky tape is up instead of down.

 

[macten]

As has been said, thermal boards on top of ply, then UFH mat, then encapsulate in SLC and tile.

 

[ptoddy26]

I'm ok taking them up and staring again. But if I do as said above and the adhesive hasn't bonded is it the adhesive? I'm just trying to understand why in my pictures above the adhesive isn't stuck to the floor and if I go a different route, as above, can I use the adhesive I have or do I need different?

 

[Tony73]

Hi, did you prime the floor before tiling? Did you check if tile adhesive is not out of date? or even if its not out of date, i had palet of faulty adhesive.

 

[ptoddy26]

Hi tony73. I only primed the floor with the fastheat that came with the UFH. I didn't check the date on the adhesive but just looked now and it's 19/03/12 and I only bought it 3-4 weeks ago so must of been out of date when bought. Would that not also cause it to not bond to the tiles as well though?

 

[ptoddy26]

Looking at the bag again that date may actually be the manufacture date. The bag says 12 months from date of manufacture so I assume the date on the side of the bag is manufacture.

 

[Tony73]

yes than , adhesive should be ok, and UFH mesh dosn't stop from good bond with floor. I would spread adhesive with flat side of trowel on to UFH and then with notched side, or use SLC first, then DITRA MATT and then tile.
Maby other members will know why adhesive didn't bond with the floor.

 

[AliGage]

So at what point after tiling your floor did you use the UFH?

 

[ptoddy26]

Hi AliGage - After the adhesive I gave it 2 days before grouting then gave it another 2 days before turning the UFH on. Only turned it on for 10 minutes just to make sure it was still ok. Haven't put it back on since.

 

[AliGage]

How long does that primer take to dry, and how long did it have to dry before tiling.

To be honest i agree with Whitebeam to bury the mat first, then tile as you would and back butter. But it looks to me like the bed wasn't substantial enough the UFH was prehaps left on a little longer than 10 minutes. Or have you got VH pipes directly under the floor at your heatings been on?

 

[ptoddy26]

AliGage - I think i gave the primer 2 days to dry also. I have got central heating pipes under the floor and looking at it the tiles that are coming loose are the ones in that area. should i have turned off the heating for a couple of days?

 

[Tony73]

i'd say much longer than 2 days

 

[lukeb]

Lukeb - Ok could well be. But can you explain why and what I should of done? It's fine telling me it's faulty installation but I need to learn why.

macten - I don't think the mat is upside down as the sticky side of the tape is stuck to the floor. But even if it's upside down the only difference is the sticky tape is up instead of down.

- maybe adhesive was mixed wrong consistency-too dry or let too long and skin formed???????
- i would "back butter" tiles for improved adhesion(especially porcelain) is your tile porcelain?
- from the photo it does not look like solid bedding to me(should be)
- SLC over matting(better adhesion and you wont damage the wire+you can use Ditra(if u want spend few quid extra)

That is only my opinion but I`m pretty sure a lot of tilers will agree:smilewinkgrin: ALL THE BEST!!!

 

[ptoddy26]

Lukeb - Tiles are ceramic. Thanks for the advice. Think i'll look into the Ditra and put some SLC down to make sure after i've taken the tiles up. Luckily it's only a small room hence why I had a go.

 

[lukeb]

GOOD LUCK AND HOPE TILES WILL STAY IN PLACE POO HAPPENS SOMETIMES:smilewinkgrin:

 

[AliGage]

AliGage - I think i gave the primer 2 days to dry also. I have got central heating pipes under the floor and looking at it the tiles that are coming loose are the ones in that area. should i have turned off the heating for a couple of days?

I haven't looked it up but i believe the tech sheets (at least for the ones i've used) recommend 2 weeks before turning on your UFH, i would leave the heating off for a time around this. What i am anticipating has happenedis this:

You've replaced the floor with ply, primed and installed the matting.
You've then spread the adhesive over the matting and NOT the floor. With the heating being on there is a chance with the pipes being close to the surface is you've heated the ply. It's expanded slightly in that area and the matting has pushed the adhesive and the tile away from the substrate.

If you can get all the tiles up without damaging the matting do pretty much what people have suggested:

Make sure the heating and UFH is off!
Ensure the matting is flat, as much old adhesive has been removed.
Apply a small amount of SLC, make sure all the matting is covered.
Install ditra matting with single part flexible adhesive, and then tile on top of this. Back butter the tiles as well.

Follow the manufacturers guidelines for drying time. But i would say the heating pipes have caused this.

Good lucks and pics when complete please! 😉

 

[ythan]

I think a key problem is the fact that UFH mesh has been laid upside down.....

The mesh is then floating ontop of the heating wires (red in the photo)) thereby preventing the adhesive from being properly towelled down (through the mesh) onto the substrate. The imprint of the sticky tape on top of the (upside down) webbing can be seen on the back of the tiles....

The other problem is probably incorrect and insufficient thorough mixing of the adhesive, the use of it while it's not still fresh, and poor towelling technique ie failure to achieve to get a good adhesive bed. Finally not bedding each tile down properly. I've not found buttering of tiles to be necessary.....though i've only used porcelain tiles. The central heating pipes under the floor may have also caused the adhesive to dry off preventing proper bedding in.

I would doubt if there is any problem with the primer supplied with the UFH. Actually, I would always use thermal insulation boards on top of the substrate as the extra cost of these is soon repaid by the energy savings. Also I've only used BAL single part fastflex with UHF, and take great care when trowelling not to damage the heating wires.

One last point is that if the substrate had have been chipboard then the chipboard would have unfairly got all the blame! and other problems may have been missed. I've had no problems tiling on chipboard floors, but within the forum, i've noted that chipboard seems to get blamed for all tiling problems, and encourages, i think, unnecessary complication, and cost, of using ply overlay, backer boards, decoupling membranes ditra etc.

I'd suggest you start again, get the UFH tested to see if it can be re-used, get thermal boards, and BAL single part fastflex, take extra care with mixing and applying the adhesive, and bedding in the tiles.

good luck

 

[AJPlumbing]

Hello, check what Mapei say, but usually the recommendation is NOT to prime the plywood prior to tiling (only prime the underside and edges). But as others have suggested, I wouldn't be happy about tiling directly onto all that UFH mesh. Burying the matt in SLC first is a much more reliable method, and allows quicker tiling with a more consistent finish. Good luck sorting it out, it's never fun to have to redo work.

 

[Dan]

Got a technical data sheet for the thermal primer?

 

[diamondtiling]

Somethings moved to make the tiles pop off. Could be that you should have primed the underside first and now the ply has bowed up. Fitting the underfloor heating upside down should not cause the problem. I always glue (expanding foam, takes the squeak out of floors) and screw the ply down, then use backer boards, did you use zinc coated screws? Not that that would cause a problem early on.

 

[AJPlumbing]

Got a technical data sheet for the thermal primer?

Thermal floor primer | FastHeat? | underfloor heating

 

[Marekcygan]

Hi Mate

We are very experienced tilers and I am flooring contractor too.

We were really like to use mapei adhesives especially flexible but unfortunately there something happen to their tile glue.

The adhesive what you have used is quite new on the market and I have tried it recently and believe me it is not your fault .

The adhesive is suitable for concrete floor maybe and it dries long time , 3 days but for sure it is not flexible .

Mapei wasted my project and I will be claiming money back for materials at least.

Regards
Marek