My porcelain kitchen tiles are lifting - help.....

[d8wyt]

Yes! I cannot understand how if we used the wrong ply why the whole floor and grout is not lifting and cracking and it is only in specific places. We have put the same flooring throughout 3 rooms e.g. utilty, kitchen and breakfast room and it is only lifting in part of the utility and kitchen?

 

[hillhead]

How did your husband apply the adhesive?
Did he put blobs on tiles and place them on floor?
Spread on floor with a notched trowel?
Spread on tile with trowel?

 

[d8wyt]

spread on the floor with a notched trowel!

 

[hillhead]

Thats the right way plus the flat edge to put adhesive on the back of the tiles help the bond too.
You have the wrong thickness of ply, this alone can cause tiles to lift. There is movement through this ply.
If adhesive was setting too quick then bad bonds are likely in areas too.
Most could fail over time !!
Bad news i know, temporary you could lift and re stick affected tiles with a two part adhesive S2 grade and keep fingers crossed but good luck (you'll need it).

 

[Daz]

It seems to me that the wrong materials have been used, i.e. plywood. The plywood that you have used is even more vulnerable to moisture than 18mm (which is still slightly "iffey"). You said that the adhesive seemed to go off quickly, so I would assume that the first few spreads from the mix were wetter than the latter spreads, therefore there will be more moisture exposure in localised areas.
Did hubby prime the underside and sides of the plywood prior to application?
Was the face of the plywood primed prior to adhesive application? If primed, what primer was used please?

Has the problem occurred in areas where there is high foot traffic?

Daz

 

[d8wyt]

Thanks you have really helpful - we shall try the above and hope for the best!!

 

[d8wyt]

I would say medium traffic - not as high as other areas which are not lifting! Yes primed, don't know make!

 

[Daz]

I'd hazard a guess that the plywood has delaminated causing the tiles to "blow". When you lift the failed tiles you need to check the plywood for blisters or splitting. If the plywood is damaged then you will need to replace it (not 6mm again though):mad2:.

Good luck,

Daz

 

[philipb]

Hi there,Two things,first there are two types of ply,one is ok for floors and one is not.You can tell with the price,
the one that is ok for floors is twice the price of the other.if you got it from say b and q it will be ok.If you got it from a timber yard and got it very cheep it will be no good for floors due to the poor adhesive used in manufacture which can cause
the layers to seperate.also the reason the problem is just in one or two areas is due to spring in the floor.Its common in newer houses.You will have to lift the floor and put nogins under the floor joists to give it more support.
once you take the spring out of the floor relay with at least 9mm screwed every 100mm.
Also use an elastisizer added to the adhesive for more flex,dont forget to screed the ufh first and leave overnight
before laying the tiles.
philipb

 

[hillhead]

9mm is not recommended Philip.Minimum of 15mm is.

 

[philipb]

Yes i hear what you are saying,but if he only has problems in two areas,that means that
most of the floor has been ok on 6mm,in a case like this i would rectify this by putting extra support in the two areas
by way of nogins to take any spring out,increasing to 9mm and making the adhesive more flexible/
Are you saying you use 15mm ply on all the floors you tile no matter what?

 

[hillhead]

Yes i hear what you are saying,but if he only has problems in two areas,that means that
most of the floor has been ok on 6mm,in a case like this i would rectify this by putting extra support in the two areas
by way of nogins to take any spring out,increasing to 9mm and making the adhesive more flexible/
Are you saying you use 15mm ply on all the floors you tile no matter what?

I see where you're coming from here, yes by adding noggins and underpinning the joists basically you're stabilising the floor and curing bounce therefore leaving a strong set up.
I have used 9mm before on floors and no bounce worked well but most people don't want the extra cost of an S2 grade high flex adhesive.
Most ply now is from china and even the so called good stuff is crap too, i have seen 18mm delaminate before my eyes just with tanking applied.
It's a maze out there with the dreaded ply as i'm sure you know.
Good description there of re supporting the floor Philip.

 

[Daz]

Can I also throw this thought in.....
Philip, to add extra noggins you will need to lift the whole floor. This contradicts the OP's original request to not have to lift all of the floor and, means that you will potentially compromise the so-called "stable" elements of the floor, too.

If the OP were to elect to add extra support then surely the only sensible procedure after adding noggins is to replace the floor boards with 25mm ply, then overboard with 6mm cement boards prior to tiling. That way the floor will be deflection free and stable for tiling???

Daz

 

[DHTiling]

Yes i hear what you are saying,but if he only has problems in two areas,that means that
most of the floor has been ok on 6mm,in a case like this i would rectify this by putting extra support in the two areas
by way of nogins to take any spring out,increasing to 9mm and making the adhesive more flexible/
Are you saying you use 15mm ply on all the floors you tile no matter what?

Are you actually a tiler.?

BS5385 does state 15mm minimum..

And adding noggings takes the twist from joists not deflection.. if a joist deflects then it is not deep enough for the span..

 

[philipb]

Hi Dave,I am not disputing bs5385,i am just trying to help the guy,the nogins are to support the floor and take any bounce
or spring out,they go under the joists to the subfloor,i know its not an exact science,but in a case like this
it will help give extra suppot in the affected areas.

 

[DHTiling]

Hi Dave,I am not disputing bs5385,i am just trying to help the guy,the nogins are to support the floor and take any bounce
or spring out,they go under the joists to the subfloor,i know its not an exact science,but in a case like this
it will help give extra suppot in the affected areas.

Phil noggings go between joists,you are talking about supports but the point members disagree with is your recommend of 9mm ply


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[redrex]

Well hello everyone! It's been a while since i've posted but I have been dipping in and out now and again. Nearly a year and a half since I had too take a break but looking at picking up the tools again. This thread caught my eye, as it seems to be a very similar situation to one of the previous jobs I had. A couple of pics for you but essentially a similar issue. Lack of support to the sub floor with underfloor heating, incorrect addy/inadequate depth, no expansion joint to change of substrate. In this case, I stripped the floor (that sounds so simple, doesn't it?:lol added some supports, substituted 18mm for 15mm ply to allow extra bed depth, 2 part addy,flexy grout, expansion joint, refit woodwork, paint, silicone and job done. As usual, the tricky bits were getting the old ply up and making sure I kept as many tiles intact as possible, having no spares. As a happy aside to the work, the 1/3 tile across the room then allowed a much nicer set out to that end of the room.

Advertisment over! Seriously though to the OP, It is probably possible to fix the problem but IMO it will require that section of floor to come up. If you are anywhere near me, happy to have a look for you. A quick fix is possible but unless you start over, the problem will happen again.

Pics for you...