Tiling over tiles with lippage. - Tile Advice

[PeteySands]

Hi all.

Advice would be appreciated on whether I should use some sort of levelling compound to even out irregular lippage on the existing tiles before I start, or whether I should be okay with back buttering or otherwise increasing/ decreasing the height of adhesive whenever I encounter a troublesome area.

I'm a first timer, looking to tile my kitchen splashback with 6mm thick 10x30cm metros. I need to tile over the existing tiles, which are 10x10cm. The previous job looks 'okay' but there are definite areas where small lips protrude between tiles, which I'm assuming over the course of the area will result in my over-tiling being noticeably uneven.

I've seen loads of posts about floor levelling screeds and the like, but not much in relation to what I might use to even out my wall, or even whether I actually need to do so. I wondered about attacking it with an angle grinder but not sure whether I'd be on a hiding to nothing going down that route.

I'd really welcome any advice about what product I should use.

Thank you

 

[bsc ceramics]

Welcome to the forum.
I know its a pain but if i were you i would take off the old tiles
and start again. make any repairs so you have a good base to work on
but if your careful taking them off you should be ok.
Good luck and let us know how you get on

 

[PeteySands]

Thanks for taking the time to reply, BSC.

Yes, I think I'm ready to admit that removal of the old tile is the only chance I stand off getting a good finish. I had a go with the grinder but I'm just adding more bevel to an already beveled tile.

I've taken off a few tiles but a lot of plaster board is coming off with the adhesive. I'm gonna rip them out and install new plaster board. My wife's gonna love me.

Once I do that, do I need to do anything to prime the surface or do I just whack the adhesive straight on top?

 

[bsc ceramics]

Its best in the long run. just prime the boards before you tile
with an aycrilic primer not pva.
Put up some pics when your done.
Good luck 👍

 

[PeteySands]

Yeah I'll do that. Thanks again.

 

[PeteySands]

Hi. Hoping for another piece of advice regarding my prep. I've ripped the tiles out now but as suspected the vast majority of plasterboard came off too. Bought some plasterboard so not a big deal. Got some scrim tape for the seams too.

 

[PeteySands]

.

Hi. Hoping for another piece of advice regarding my prep. I've ripped the tiles out now but as suspected the vast majority of plasterboard came off too. Bought some plasterboard so not a big deal. Got some scrim tape for the seams too.

Sorry must've sent too soon.....continued..

...Problem is that because the plaster was coming off so freely, at the far side where the area to be tiled meets a tall kitchen unit (housing cooker etc), I wasn't able to salvage enough of the old board to create a seam with the new; it's cut right to the edge of the cabinet. I was as careful as possible but it just wanted to pull off with every old tile. It's also another 8cm or so until the next stud, which is unreachable behind the cabinet, therefore my new plasterboard will essentially be unattached at that end; not screwed, not taped.

Do I run a serious risk of this leading to the grout cracking one I've tiled, as the substrate contracts and expands with the climate?

Removing the cabinet to board to the next stud is really not an option for me for reasons I'd rather not get into. Are there any other trade tips that might help me in this situation? This job doesn't need to last decades, just 3 or 4 years until we get the kitchen properly done with an extension, so I'm not seeking perfection.

 

[Travee]

.

Sorry must've sent too soon.....continued..

...Problem is that because the plaster was coming off so freely, at the far side where the area to be tiled meets a tall kitchen unit (housing cooker etc), I wasn't able to salvage enough of the old board to create a seam with the new; it's cut right to the edge of the cabinet. I was as careful as possible but it just wanted to pull off with every old tile. It's also another 8cm or so until the next stud, which is unreachable behind the cabinet, therefore my new plasterboard will essentially be unattached at that end; not screwed, not taped.

Do I run a serious risk of this leading to the grout cracking one I've tiled, as the substrate contracts and expands with the climate?

Removing the cabinet to board to the next stud is really not an option for me for reasons I'd rather not get into. Are there any other trade tips that might help me in this situation? This job doesn't need to last decades, just 3 or 4 years until we get the kitchen properly done with an extension, so I'm not seeking perfection.

Here is me rambling for a bit...I've had this exact project many times. Yes. Tearing out all the plaster or drywall and putting all new stuff in is the way to go, but it's common to run into issues with the studs not being in the right spots, more on that in a bit...

Priming the new drywall is not a terrible idea, because it will add a layer of moisture protection, but personally I don't prime the new drywall, or use mesh tape on it, or do any filling with drywall mud. I fill and level the edges and holes in new drywall with the thinset mortar because it sticks great to the paper of the drywall. If a new drywall piece butts up to existing drywall, it's common for the new stuff to appear thinner, because it doesn't have as many coats of mud. Use thinset there to make a gradual transition between old and new. The new tiles are longer, so you want to try and make the wall as flat as possible, without curves or sharp bends, to avoid lippage. It can be a bit of a pain in the *** with the usual switches and sockets in the way, so I recommend masking those off, and using maybe a 5" drywall knife, to apply this prefill coat of thinset.

As for the edge meeting the cabinet, where there is no stud, try to secure a large piece so it is as solid as possible, but don't stress about it too much. Because the new tile and grout will give it a lot of rigidity, as I am sure you noticed while tearing out the old stuff. Try to pack some thinset in where the drywall meets the cabinet, but careful to wipe off the extra. Then after things are well grouted, don't forget to add silicone against the cabinet and countertop. This is good practice to keep grout from cracking out, but it also adds a ton of strength. Silicone is regularly used to secure massive panes of glass in showers, without any additional hardware. I haven't had any problems using this approach, but you could also add a bit of backing along an edge by adhering a strip of lumber along the back side of the existing drywall, to screw a new piece into. This is up to your discretion. Good luck, hope this helps a bit.