How to install laundry backsplash on wonky wall?

[KTProjects]

Howdy, 

I'm completing a laundry reno with only the backsplash tiling to now be completed. I was well aware that I had a few shy studs but didn't want to gut the whole room so I'd shimmed all my cabinetry when installing and at the time was hoping to just float the tiles as well. Iooking at the gap between my benchtop and the wall, I can see I'm shy by as much as 5mm which I've read is too much to float a tile.

Removing the plaster and shimming the studs is no longer an option, should I use a backerboard over the plasterboard, using shims to mount it flat?

What should by shim spacing be on the stud? 

Can I get away with slapping on more morter where the wall is shy?

 

[EricL]

Hello @KTProjects 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your questions about your splashback.

If your wall tile is about 5 to 7mm thick keep in mind that you will need the same thickness of adhesive to mount it on the wall. Therefore, the total thickness of the tile plus the tile adhesive will be greater than 5mm. 

However, if you are worried about the gap, installing a backerboard is also a good idea as it will give you a totally flat surface to mount the tiles.    

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[KTProjects]

Sorry I'm not sure if I explaned correctly. The wall is not flat, it bowes in 5mm at the centre of the countertop, so the tile adhesive would have to have an additonal 5mm of thickness in this spot for me to achieve a flat tile. My concern about using a backer is that im eating an addtional 6mm into my worktop

[Dave-1]

Good Evening @KTProjects 

I agree with @EricL's suggested solutions. Walls are never even, a 5mm bow I would still think the glue plus the new tiles can cover this. 

A board could help even the wall out but the shimming of it may be problematic. How high are you taking the tiled splashback?

Dave

[EricL]

Hello @KTProjects 

I believe that 6mm is an acceptable compromise to your benchtop space as the payoff will allow you to have a flat surface from which to tile on.  

Eric   

[Nailbag]

Hi @KTProjects 

There is a limit to how much adhesive you can use to make up for the unevenness of the wall. Too much, and the tiles will move whilst laying. Then there is the issue with shrinkage of the adhesive (amount depends on type) which, could result in tiles dislodging or possibly cracking. Knowing exactly your restrictions would mean contacting the adhesive company for their advice.

Adding another layer to the wall with tile cement sheet would be your easiest solution for the small amount of bench space lost. You just need to take note of the remaining space between the back of the mixer and the wall. 

Removing the plasterboard, packing the studs and replacing it with cement sheet would be the way I would go. It's not that big a job and result in a much nicer finish between the mixer and tiles. Using a combination of a multitool and plasterboard stab saw make a cut a few mm in of the cabinetry and benchtop, then a few grab holes in the middle of the wall to pry the board out (in pieces). Clean the glue or and remove any fasteners would be less than an hours work. Use packers to level the low-points and install a cement sheet a few mm's shy of the opening to make it easier to fit.

Nailbag