Tiling over painted gyprock without underlay

[Abba]

Hi All,

Could you please help me out?

I want to tile a kitchen splashback with black polished porcelain tiles 300x300. I have a lot of leftovers in my garage including ABA Primer and two component Isoflex tile adhesive.

I want to tile over existing painted gyprock without putting fibre-cement sheet. The plaster is painted with a couple of layers of water based acrilic paint two months ago.

Now questions:

1. Can I tile without fibre-cement sheet underlay?

2. If yes, can I simply roughen the surface mechanically ? Must I totally strip the paint away?

3. How much space do I need to leave between the tiles, 1.5 mm?

4. Can I use the Isoflex adhesive I already have?

Thank you in advance

[Pulse]

Hi Abba, tiles won't stick effectively to paint.

Read the info on the back of the tile adhesive, usually 80% of the paint would need to be removed mechanically prior to tiling. The other option would be to mechanically attach ceramic tile underlay as you stated.


Cheers
Pulse

[Honorary Bloke]

Hi Abba,

Pulse is correct. The tile will stick to the paint, but will the paint stick to the wall? Probably not.

But, if water is not an issue on your backsplash, I have done this: Cut a piece of 4mm smooth-faced ply to lay behind the tiles and mechanically fasten it to the wall. Cut it so it is about 5-10mm short of the tile height. Then, install the tiles over the ply and fill the small gap at the top with silicone. The ply won't show and you will have a solid backing.

Again, not recommended if you will have a lot of water on those tiles. Good luck.

[MrFixIt]

I want to tile a kitchen splashback with black polished porcelain tiles 300x300. I have a lot of leftovers in my garage including ABA Primer and two component Isoflex tile adhesive.

I want to tile over existing painted gyprock without putting fibre-cement sheet. The plaster is painted with a couple of layers of water based acrilic paint two months ago.

Now questions:

1. Can I tile without fibre-cement sheet underlay?

No, especially as the paint is quite new.

2. If yes, can I simply roughen the surface mechanically ?

Roughening the surface will be messy as the paint is still "soft" and I expect will become quite "fluffy" as you attempt to roughen it.

Must I totally strip the paint away?

HIGHLY recommended, particularly with larger tiles. The fibre-cement method is MUCH better. A problem you will have is being able to strip the paint away from the gyprock without damaging the gyprock's paper surface. This remaining poor surface may also become detrimental to the use of tile adhesive. Gyprock itself is a very soft material and relies on the paper binding for it's rgidity.

I DO suggest you go with the fibre-cement sheeting. You can then RELY on the surface and know that (if you lay the tiles properly) the tiles will not become loose or unstable.

3. How much space do I need to leave between the tiles, 1.5 mm?

Usually a compromise between personal preferance and the size of the tile being used. Personally I think 1.5mm is a little "tight" for 300x300 tiles. You can but the little "+" spacers at differen sizes. Take a couple or three tiles with you to a tile shop or Bunnings and try them out for your preferred appearance.[quote]

4. Can I use the Isoflex adhesive I already have?

I guess it depends on how old it is.

[Abba]

Thanks for the replies, you guys are the best!

I think I will use a cement sheet on the large areas. I have a couple small areas which I hoped to keep thin so I probably will remove the paint with a hot air gun and tile over the drywall.

Thanks once again.