weird problem

[penno]

Tiled a splashback about 4 weeks ago, ceramics, used White star, grouted next day. 3 days later customer phoned me to say the tiles on windowsill had "lifted". Took a look and the tiles were stuck firmly but had rose on an angle somehow.
Weird i thought so relaid fresh tiles with a rapid set. Few days later same call again. Window sill is wooden. This has me confused, never come across anything like it, especially as both tubbed and bagged gear has been tried on it. Think my only option is to totally remove the wood from the sill and plasterboard it out.
Anyone any idea atall why this would have happened?

 

[Fekin]

Does sound strange penno, no idea either.

If it was a moisture thing, coming through the sill then the addy wouldn't have stuck :huh2:

 

[grumpygrouter]

I could well be moisture related. If moisture has got into the timber, I may have swollen from the bottom (perhaps) and pushed up making the tiles appear to have lifted. If the adhesive was solid and the tiles still securely fixed, it doesn't seem like a fixing issue to me.

Something else amiss here methinks.

 

[Fekin]

That's what I initially thought, but it's a drastic amount of movement over a few days though.

 

[DHTiling]

It is just as you guys think..its the moisture from the adhesive and grout causing it to swell slightly and dry back but still leaving the hump......I tend to either take the wood cill off or board over with plasterboard........also if leaving the timber cill on then it is worth putting a couple of extra fixings in to make sure it is solid....

 

[Fekin]

I thought it was a long shot idea as I didn't really think the cill would bloat up with the addy n grout moisture to that extent... you live n learn

 

[DHTiling]

yes! adam , more likely to happen with tub gear than powder......as the powder gear should be rapid setting so not giving enough time for moisture to effect it..
Also depends on how moisture sensitive the timber is......so if enough height is there in the frame then plaster board it....if not remove and re-board......

 

[enduro]

If you put acrylic primer on first and let that dry would this still cause the same problem?

 

[DHTiling]

It will slow down the moisture to wood suck ratio.....Use APD neat........

and rapid set with Ad1 additive , faster setting than flexi.......

 

[sibs]

It is just as you guys think..its the moisture from the adhesive and grout causing it to swell slightly and dry back but still leaving the hump......I tend to either take the wood cill off or board over with plasterboard........also if leaving the timber cill on then it is worth putting a couple of extra fixings in to make sure it is solid....

Dave is it easy to take a window cill out? Do you just cut it out with a fein tool ? I mean they're recessed into either side of the wall so do you just cut off what you need to or do you take the whole lot out?

 

[Perry]

It is just as you guys think..its the moisture from the adhesive and grout causing it to swell slightly and dry back but still leaving the hump......I tend to either take the wood cill off or board over with plasterboard........also if leaving the timber cill on then it is worth putting a couple of extra fixings in to make sure it is solid....

Dave you dont need us lot mate you have been around to long lol
you should always use rapid on timber even ply as you can get the same problemsete

 

[uug197h]

we have had same problem now we plasterboard the window sill but if you have tilled the walls you will not want to remove the wall tiles you may get away with screwing 4 mm ply on the window sill then tiling over it

 

[howard]

It is just as you guys think..its the moisture from the adhesive and grout causing it to swell slightly and dry back but still leaving the hump......I tend to either take the wood cill off or board over with plasterboard........also if leaving the timber cill on then it is worth putting a couple of extra fixings in to make sure it is solid....

Dave could the cill still swell if it was a painted surface ?

 

[penno]

thx for all the help

 

[Perry]

we have had same problem now we plasterboard the window sill but if you have tilled the walls you will not want to remove the wall tiles you may get away with screwing 4 mm ply on the window sill then tiling over it

4 mm backerboard would be better ply would have to be glued and screwed to stop it daminatingete