Shower enclosure backing advice

[LdA]

Hi all,

I'm retiling an existing shower enclosure in a Victorian Terrace which is brick on one side and concrete blocks on the other two. My hope was to install some sort of backing board on all three walls (or at least on the the brick wall) and then tank before tiling, however all the backer board installation guides seem to imply that I can only fix to wood framing and there simply isn't room to batten out the space (it's barely 760mm wide from bare brick wall on the right to concrete blocks on the left).

Any suggestions as to the best way to prepare these surfaces for tanking and tiling?

Thanks!

 

[Richard C]

You can initially dot & dab waterproof tile backer boards (I use Aquapanel) level but it’s essential you provide mechanical fixings in addition. The fixings should be on a 250-300mm grid pattern (I drill 3mm pilot holes) & be fixed through the adhesive dabs (use through frame fixings next day after its set) or you will crack the boards when pulling them up. No real need to tank the boards unless you have a wet room of very powerful shower, just reinforce tape the joints & fill with adhesive as you tile. What size/type of tiles are you using? Are any of these walls external solid brick?

Tiling isn’t rocket science but there are still many things that can catch you out. With walls, you need to consider tile weights, prep & materials & suspended timber floors need special consideration. I would advise you read the Tiling Sticky & Forum Archive posts before doing any work or buying materials, it could prevent you making disastrous & potentially expensive mistakes. It’s also important to use only quality trade tilling materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap.

Post back if you need more info.

 

[LdA]

I had done the tiling previously (about 8 years ago), but was given bad advice and had fixed them to plywood. The shower tray was also cheap and badly seated so the sealant around the tray failed frequently, causing the ply to wick up the water and rot and then proceed to rot the floorboards underneath. Needless to say, I'm now quite paranoid and so was hoping to make it as water-proof/resistant as possible, hence the tanking.

None of the walls are external. The brick wall is the one between mine and next door, but is the one that is the most concern to me. It needs some sort of facing as it's very uneven.

Can I tank and then tile directly onto the concrete blocks? The bal waterproofing kit implies I can. It would give me much needed extra space in there.

The tiles are 100x200 metro tiles. I imagine larger would have been better, but they were cheap and I like the look.

I'm now reading advice about upstands so I'm glad I haven't bought a new shower tray yet!

 

[Richard C]

I had done the tiling previously (about 8 years ago), but was given bad advice and had fixed them to plywood.

Yes I’m afraid that was extremely poor advice.

None of the walls are external. The brick wall is the one between mine and next door, but is the one that is the most concern to me. It needs some sort of facing as it's very uneven.

That’s fine; sounds like an ideal candidate for direct fix boarding.

Can I tank and then tile directly onto the concrete blocks? The bal waterproofing kit implies I can. It would give me much needed extra space in there.

Can you tell me exactly what type of concrete blocks they are? Again, you can tank but it’s not usually necessary although it may be advantageous in this case depending on what type of blocks they are; you will need additional prep if they are lightweight blocks as opposed to the older medium/high density blocks.

The tiles are 100x200 metro tiles. I imagine larger would have been better, but they were cheap and I like the look.

Hmm I don't like those things much; always reminds me of old Victorian public tiolet blocks you used to see in market squares. They look OK as a straight tiled splash back in a kitchen but you need to think carefully about how you fix them due to the beveled edges, especially in corners & trying to lay them brick weave will give you a whole lot more problems; get it wrong & it’ll look like a pigs ear. You should be OK with a decent tub mix with those but I'll confirm later.

I'm now reading advice about upstands so I'm glad I haven't bought a new shower tray yet!

Again, not particularly keen on trays with upstands; personally I prefer to fit a decent stone stone resin tray if I can; no less reliable if correctly done.

 

[LdA]

Can you tell me exactly what type of concrete blocks they are? Again, you can tank but it’s not usually necessary although it may be advantageous in this case depending on what type of blocks they are; you will need additional prep if they are lightweight blocks as opposed to the older medium/high density blocks.

Hmm, not really sure. I'm going to take a wild guess and say the shower enclosure was built about 20+ years ago. They're not the sort with a hole in the middle, if that helps.

Hmm I don't like those things much; always reminds me of old Victorian public tiolet blocks you used to see in market squares. They look OK as a straight tiled splash back in a kitchen but you need to think carefully about how you fix them due to the beveled edges, especially in corners & trying to lay them brick weave will give you a whole lot more problems; get it wrong & it’ll look like a pigs ear. You should be OK with a decent tub mix with those but I'll confirm later.

Yeah, that's pretty much why I like them. I've actually got them brickweave in the kitchen as well - including corners. The tiling bit I'm quite good at (if I say so myself), but experience tells me that I need to prep much better than I did in the past - in a shower at any event.

Again, not particularly keen on trays with upstands; personally I prefer to fit a decent stone stone resin tray if I can; no less reliable if correctly done.

OK - good to know. I've read various on this forum. The ones with upstands are harder to find, but the tray was my biggest issue with the previous installation. Firstly because whoever installed it initially (not me!) just propped up a lightweight acrylic base on loose bricks, which made the whole plywood thing more of a disaster than it would have been on its own. I'll check the sticky for shower tray advice before buying one.

 

[Richard C]

If they are only 20 years old they are likely to be lightweight blocks, do they look like Thermalite’s?

 

[LdA]

Hmm, hard to say. They don't have the curvy pattern in them like the photos online, but the material looks the same - colour and texture.

 

[Richard C]

Is it very soft, can you almost scrape it off with your fingernail?

 

[LdA]

Oh no. It's hard - like proper concrete. It would be a complete nightmare to take down, I expect, which is why I'm pretty well stuck with the pathetically small size of it!

 

[Richard C]

Direct tiling onto lightweight blocks isn’t recommended with ready mix & you need to prime with powder adhesive but if you really want to tank it, then you should be OK to tile straight over the top of that with some thing like BAL Grip or White Star as long as the surface is reasonably flat, if not switch to powder as you can lay that on much thicker.

 

[LdA]

Brilliant. Thanks very much for all your help!