Tiling over tiles advice required.

[rustylt2]

I've been out to look at a job which will require tiling over the existing tiles and this will be the first time I have done it, so any advice appreciated!

It is 27sqm of bathroom walls and all the tiles appear sound except for 2 rows of tiles above the bath, which are boast. The owners say they have had the walls and roof checked for any signs of damp or leaking and there is none, but these 2 rows have managed to come away (the tiles have been on about 20 years).

The new tiles will be ceramic (300 x 200mm I think) while the exsisting tiles are smaller ceramic. I had read somewhere that a good tip is to mix a little sand with PVA and paint it onto the walls. When it dries it will leave a good coarse surface for the adhesive to grip to. Anyone tried that? Also, anything I need to know regarding type of adhesive other than using the usual waterproof powder mix?

There is also a seperate shower cubicle, so is it OK to tile over tiles in a shower?

Just want to get my facts right before I go back to the customer with a quote!

Thanks guys.

PVA big no no with tiles. There is an excellent post on here somehwere with a link to a detailed explanation.

I wouldn't go tile over tile in a shower area. You don't know what condition the substrate is in underneath the tiles i.e. was it tanked. Adding extra weight may just bring the whole thing down.

[Dave]

hi rustylt2...
My advise is to remove the old tiles and make good the walls...tiling onto tiles isnt the best method.....you should never use P.V.A. to prime walls....always use a suitable primer...i use bal prime APD and bal bond SBR follow intructions on the bottle......

Here's the reason why not to use p.v.a......................http://www.tilersforums.co.uk/tiling...s-primers.html

[rustylt2]

Hell's teeth! That's an eye opener on the PVA....definitley won't be using that then! Would the same trick not work work with a suitable primer then? I mean mixing a little sand to give a coarse surface to tile onto.

I take the point about tiling over tiles in the shower but I thought it was not unusual to tile over exsisting tiles if they are sound. I know the best thing to do would be to remove all the old tiles but it would be a hell of a job as the walls may need plastered again depending on the state of them after the old tiles come off. ( the house is 1930s with no stud walls btw)

Thanks for the replies so far.

I think tiling on tiles in a bit of a personal choice. I don't like doing it as you just don't know what is going on behind the tiles. For example, what condition is the substrate in, how much coverage have the old tiles got, what the total weight will be etc etc.

With regards to removing the tiles, I find the easiest thing is to remove tiles, if the condition of the wall behind is no good, rip that off too and then dot and dab some plasterboard to the walls. You then have a near perfect surface to put the new tiles on.

As for the sand in the primer I don't know the answer to that, sorry.

[Varley]

Here is a little word of warning about tiling over tiles...

I went out to tile a kitchen floor about a year ago, customer wanted me to tile over existing tiles, I sounded them out and there were a few too many hollows for my liking so I said tiles would have to come up. Customer said fine if it was the only way.

Went out to start ripping up the tiles only to find that the ceramic tiles I was ripping up were tiled on top of old quarry tiles, which I ended up removing aswell.

My point is...imagine if that was on a wall! the weight ratio of adding a third layer of tiles could be dangerous (which is the point McP77 is making), and how would you know that there wasn't another layer of tiles on the wall if you aren't taking any off .

Best advice I can give is don't tile over tiles, expecially on walls, your relying too much on someone else's work to hold yours on.

[Dave]

Exactly martin mate..very well put........dave..

[rustylt2]

Thanks for all your advice guys...looks like removal of the old tiles is the only safe option. I will put that to the customer when I go back next week. Cheers.

[devonmark]

Hi Rusty, If you don't feel comfortable tiling over tile..don't be afraid to turn the job down if the customer won't take your advice..a good reputation is made over time and with a lot of hard work, it can be destroyed with one job. If you miss out on this job there will always be more.
Mark.