How do I fix this mess?!

[terryplumb]

Dry as a bone. It wouldn't surprise me if it wasn't put on right in the first place. We've learnt a lot of the newer additions in this house had been done on the cheap and don't seem to be super high quality!

As taking some other boards off has left some small damage, to be expected, I'm going to bonding plaster route.

Also discovered my dad does have a tile cutter, so all good on that front!

Check out British Gypsum's websites. They make bonding plaster and advise it is NOT suitable to tile onto.

 

[ChilliBob]

Thanks, Terry, that's a shame. I've looked and yes, you're right. I was actually tossing up between Bonding, Bonding 60 and Undercoat from Thistle. I can see that Bonding and Bonding 60 they say no, don't put tiles on. Undercoat (available from Tool station, yay!), it seems is okay in some cases.

https://www.british-gypsum.com/~/me...histle-Undercoat-Plaster-Convenience-Bags.pdf

Tiling
Tiles of up to 20kg/m² can be applied directly to the
Thistle finish except where the system includes a bonding
agent. As the total weight of tiles and plaster applied
over a bonding agent is limited to 20kg/m², consideration
should be given to tiling directly to the background.
When plastering to provide a background for tiles, avoid
‘polishing’ the finished surface. Polished finished surfaces
should be roughened and a suitable primer used

As these are small tiles (they'd be around 100mm tall, and probably 120-140 wide, thin small tiles, the weight wouldn't be an issue.

I did consider the plasterboard idea quite a bit, but with some plaster still rock solid and sound I would have had to cut quite a creative bit of plasterboard, plus with a few other fixes I had to do the plaster route seemed more economical.

Do you guys reckon with the undercoat it'd work? - To think I wasn't too fussed between the different bonding/undercoat ones - seems they're quite different then!

 

[terryplumb]

You are misreading their info ,which is referring to a finishing plaster on top of the bonding. Bonding plaster ,and tiling directly onto it has two issues ,suction and moisture absorption. The bonding sucks moisture out of the tile adhesive ,and makes a weak bond.

 

[ChilliBob]

Ah I see that now I re-read it. Bugger!..... If I can't go down the plaster board route, is there any form of plaster/liquid filler that I can use which I can tile over? I've read on other forums about PVA on top of undercoat but also seems this is not recommended. Such a pain just for 2-3 tiles!

 

[terryplumb]

Never tried ,as its so simple to dot and dab a piece of plaster board onto the wall.

 

[ChilliBob]

But what do I do about the fact that some of the render is still stuck to the wall, very well. Just cut the plasterboard into as close a shape as I can, then stick it to the wall?

Regarding this dot and dab side of things, this is such a small area, we're talking probably 2x plasterboard which would be say 150mm x 250mm or something... so I'd just put blobs on the perimeter of these boards say the size of a 50p, then push it hard into place on the bricks making sure it's aligned up nice?

Then just tile onto that? If there's some tiny gaps between the existing render and the plasterboard, I'm guessing that's not a huge issue? - e.g. say something you could get your little finger into - it's still a solid enough base to tile on

If I'm doing that I might get a bag of EasyFill for the other areas I need to patch repair (which then have skirting applied, not tiles).

 

[terryplumb]

A few blobs the size of golf balls should do ,and not too close to the edges of the board , something like the 5 dots on a dice if your with me. You don't need to cut the board with surgical precision !!
Any gaps can be filled with the DRI wall adhesive ,it sets Rock hard.
Existing plaster that's solid you don't need to worry about ,leave it be.
By the way ,you blob the adhesive onto the brick ,then tap the board onto it. Don't put the adhesive onto the board.

 

[ChilliBob]

Okay cool, I reckon I'll get the Knauff stuff from Wickes, 25kg, lol, I'll not need much. So if it's a 12mm depth I need I'm thinking 9mm plasterboard then the adhesive will add a couple of mm to get me to the correct depth to be level ready to tile. Golf ball sized blobs (I get the 5 blobs on a dice bit) do sound massive when you're talking a bit of plasterboard perhaps about the size of a vhs casette (quite why that's the first thing which came to mind I don't know!).

So I do the blobs on the brick wall, besides dusting, anyt other prep for the wall - spray and let dry with water, warer/pva mix or anything?

Then press on, and if some splodges out just wipe it off.

Then it should cure rock solid within a couple of hrs?

Side note - seems I'll be left with 24.5kg of this stuff, seems I Can use it as a bit of a crude filler, any other uses for it?! Otherwise it'll sit in the shed till I do a tip run Boo! hate wastign stuff

 

[ChilliBob]

Oh and thanks for bearing with me Terry, your advice is much appreciated, tons of other 'life' stuff going on around me at the moment, I'm not usually as useless! Just quite distracted.

 

[terryplumb]

I am pretty sure you can buy smaller bags .
Just wash the bricks with wet cloth to remove dust ,that's it.
Your pics look as though the area is bigger than a VHS cassette !!
You could use the stuff to fill deep holes ,but you won't really get it to a smooth finish ,its not a filler . It does however set rock hard to a fair old thickness ,and it sticks like chit to a blanket !!

 

[ChilliBob]

Must be a funny angle then. The bit that's missing I'd need two bits of plasterboard about the size of a VHS I reckon, actually, smaller tbh.

Nice, so for some rough bits left from pulling skirting this should work fine to take those in a bit before skirting is applied - not like it needs to be top drawer finish for that.

B&Q sell a smaller bag of their own stuff, but the reviews suggest it's sh1t so for 3-4 quid difference thought I'd roll with the knauff stuff.

 

[ChilliBob]

https://www.wickes.co.uk/Knauf-Gypsum-Based-Plasterboard-Adhesive-25kg/p/141933
https://www.wickes.co.uk/Knauf-Baseboard-Square-Edge---9-5mm-x-900mm-x-1-22m/p/220205

Gonna grab those two on Sunday, should do it I reckon.

 

[terryplumb]

I really did think you needed to repair a much bigger area. Are you sure the remaining plaster is solid ,even where the loose tiles were stuck with tape ?
Buying plasterboard and 25 kg of adhesive for the tiny areas you mention is a bit of overkill to say the least ,if you can't make good use of it elsewhere.

 

[ChilliBob]

Under those tiles is a possibility it would be lose, but if it is that's the height of one tile, so 100mm and the width there is about 12-1300. The rest of it is sound, tapping it's all good and feels rock solid.

Yeah, It does suck having to get all that for such a small area!

To put it in perspective I'll need to put back 3 or 4 tiles, tiles are 100 x 200 but in this area they don't go the full 200 wide. And on those tiles about 85% of it has come back to brick.

 

[ChilliBob]

I'm at work now, and out tonight but I'll pop a tape measure by it tomorrow morning to see if my guess measurements are on or not!