Wall Tiles Not Sticking

[Tambo]

Hi folks, hope you can point me in the right direction here

I'm putting ceramic tiles on a ply faced wall (sealed with pva), using unibond waterproof adhesive. Trouble is, the tiles are sticking initially, but then 'pop' off the wall as they dry. Adhesive is sticking well to the wall, but the tiles are coming off virtually clean.

I'm applying the adhesive to the wall, and only covering about 2 tiles worth at a time. Tiles are 250x335.

Done quite a lot of tiling over the years, but never had this before !!

Any ideas ??

Cheers,

Tambo

[doug boardley]

Hi folks, hope you can point me in the right direction here

I'm putting ceramic tiles on a ply faced wall (sealed with pva), using unibond waterproof adhesive. Trouble is, the tiles are sticking initially, but then 'pop' off the wall as they dry. Adhesive is sticking well to the wall, but the tiles are coming off virtually clean.

I'm applying the adhesive to the wall, and only covering about 2 tiles worth at a time. Tiles are 250x335.

Done quite a lot of tiling over the years, but never had this before !!

Any ideas ??

Cheers,

Tambo

the highlighted text is your problem mate, pva is not a primer and should never be used as such. When you apply your adhesive it is bringing the pva "live" again, ie back to a liquid state. So in effect you're trying to stick your tiles to liquid!

[kilty55]

hi tambo,your tiles are as big as i would go using tubbed gear,however unibond tubbed gear i found was a poor quality adhesive and would advise against pva also. switch to a better make like mapei /bal/ pci and a suitable tilers primer from the same brand and i dont see you having any issues,the unibond seems to get mentioned a fair bit on here in the way and problems your describing mate good luck

[Aztectiler]

the highlighted text is your problem mate, pva is not a primer and should never be used as such. When you apply your adhesive it is bringing the pva "live" again, ie back to a liquid state. So in effect you're trying to stick your tiles to liquid!

I'm with you Doug. NEVER EVER USE PVA AS A SEALER

[whitebeam]

Would'nt use the unibond stuff either, powdered adhesive for me

[Tambo]

Got the pva message - thanks. Presume I can use the proper primer directly over the top ?

Bit that's confusing me is that the adhesive sticks really well to the ply (despite the pva), but virtually nothing on the tiles !!

Funny thing is, it's the neatest jobs I've done - right up until they're lying in a heap on the floor

Many thanks.

[whitebeam]

Try some warm water on the pva, wait a bit then try and scrape off

[doug boardley]

is there a profile at all on the back of the tiles?

[Colour Republic]

this was my thought, although you shouldn't have used PVA you did say the adhesive was stuck to the wall, you also said that you were only spreading enough addy to stick 2 tiles at a time, so neither the PVA or skinning of the addy seems to be the problem with the tiles falling off at this moment in time... so it must just be the quality of the addy.

are the tiles really dusty?

[NETT Darren]

Trowel adhesive on the wall and do the touch test, is the adhesive sticking to your fingers alright and getting a grip on them, if so it must be something to do with the tile, dusty or wet

[Tambo]

is there a profile at all on the back of the tiles?

There's a diamond patern of ridges on the back.

Don't seem dusty at all.

As a keen amature (read moderate diy-er) my next thought was to apply the adhesive to the tiles rather than the wall. Know it's not the done thing, but it would answer the question - will it stick to the tiles.

[whitebeam]

You could apply to the wall and then give the tiles a thin skim on the back before fixing to the wall

[kilty55]

ditch the unibond mate its gash

[Oli]

What are you using to spread the adhesive on the wall, are you sure the back of the tile is making contact with the adhesive on the wall, are the peaks and troughs in the adhesive flattening indicating contact with the tile or does it remain unchanged.

Are the tiles bent, are the walls flat?

[doug boardley]

There's a diamond patern of ridges on the back.

Don't seem dusty at all.

As a keen amature (read moderate diy-er) my next thought was to apply the adhesive to the tiles rather than the wall. Know it's not the done thing, but it would answer the question - will it stick to the tiles.

1. that's your back profile
2. that's called back buttering,quite common actually, but you still need to apply combed adhesive to the walls

[Aztectiler]

I was taught to periodicly remove a recently fixed tile and check to ensure the tile has stuck properly and also to ensure that minimum 80% coverage is being maintained. This is something that I still do on my jobs after being told this over 19 years ago.

[doug boardley]

I was taught to periodicly remove a recently fixed tile and check to ensure the tile has stuck properly and also to ensure that minimum 80% coverage is being maintained. This is something that I still do on my jobs after being told this over 19 years ago.

a glass suction thingy is good for doing this, rather than risk chipping glaze by prising off witha scraper

[Tambo]

What are you using to spread the adhesive on the wall, are you sure the back of the tile is making contact with the adhesive on the wall, are the peaks and troughs in the adhesive flattening indicating contact with the tile or does it remain unchanged.

Are the tiles bent, are the walls flat?

I'm using a notched trowel. Now that you mention it - that is new, and has smaller notches than my previous (3mm ?)

The tiles squish into it (you can see the pattern left).

Tiles are flat, wall is new and flat.

I think it's a curse sent to remind diy-ers that we are diy-ers

[whitebeam]

Give the tile a slight twist or movement to work the addy into the back of the tile with a bigger notched trowel 6-7mm

[doug boardley]

a 3mm is ok for mosaics, but you need to be using a 6mm trowel at least! imo

[Dave]

So... thats your problem i think....Insufficent bed depth and has not got enough grab on the tiles....Also PVA.........never mind it can be rectified....

Deffo up the trowel size tho....and back skimming the tile helps with adhesion...

[NETT Darren]

Ive started to sell minimum 8mm trowels now for walls as tiles are getting bigger, 3mm is defo no good to stick normal size tiles on, maybe you can go down to a 6mm for kitchen tiling with 4 - 6 inch tiles, usually the bigger the tile the deeper the notch you have to fix it with, depends on uneveness of surface as well i suppose, i like 12mm trowels for the biggies about

[Tambo]

Ah, that's sounding promising. Will get 'real' adhesive and another new trowel !

Thanks for all the top advice

Will let you know how I get on.

[GirlRacerRed]

don't forget to take some photo's and post them on here when you're done! we love to see people's tiling work!

[Dave]

Please do....OH!! and how about some piccies of the finished article...we love pics you know...........







p.s GRR beat me toooo it...

[enduro]

Are they definitely ceramic tiles and not Porcelain tiles?