ATT: Joe Bloggs

[Colour Republic]

Hey Joe,

I think you need a plasterer in that bathroom of yours:yikes:

Have you been to the sister plasterers forum?:lol:

Good luck

tilersforums.com | Tile Forums | Tiling Forum - joe bloggs's Album: J.Bloggs Bathroom

 

[Deleted member 1779]

I like it... Kinda Rustic !

 

[joe bloggs]

hmmmm.... actually rustic isn't the look I'm going for.
I have tiled on the walls of this house before when I built (apart from plastering the ceiling) an ensuite about 4 years ago. The solid walls were the same material but hadn't been messed about with and the stud walls were new. As intended I'm using this ensuite while the bathroom gets done so no pressure to rush the job, realistically months to go yet.
ensuite pics in my albums, unfortunately not in order: how do I change that?

jb

 

[joe bloggs]

OK, time for me to get on with it.
I've perused the forum and am now seeking some specific advice.

The Problem: I'm tiling my bathroom with 250x400mm ceramic tiles. Two of the walls are blockwork plastered from floor to 4' with cement render, from 4' to ceiling with c1939 lime plaster. The junction of these walls is where the tap end of the new shower bath is going and one of the walls will have a lot of plumbing embedded in it. I've taken off the lime plaster skim coat (danken herr bosch) and am going to repair any lime plaster main coat missing bits with wickes 'one coat patching plaster'. I would like then to paint the plaster with some magic solution that would stabalize the plaster making it harder and less sucky and then bring the level back up to that of the cement render with wickes stuff.

The question is what magic solution can I apply to the lime plaster. (I know PVA doesn't work, I've read the posts and I've tried it. It looks OK superficially, i.e. the plaster is less crumbly and seems firm but closer inspection (digging) shows a superficial rubbery membrane on the surface, adding nothing to the stability of the mass of the plaster.) Would the products based on SBR or latex work? I need something that's going to soak into the plaster and turn it into concrete :whatchutalkingabout

I've considered the alternatives, ie

strip the lime off and render ...I can't plaster for toffee but will have a go if there's no alternative.

board it....unfortunately the bath wont fit then, its very tight.

strip it off and board it......as above still, probably. not too sure about this. matching board height with existing render could be a problem. The render is Very securely attached.

I've taken the other two walls back to stud work (was lime plaster/expanded metal lath) and will board them.

pics are here

tilersforums.com | Tile Forums | Tiling Forum - joe bloggs's Album: J.Bloggs Bathroom

thanks

 

[joe bloggs]

Any thoughts folks?:helpsmilie:

 

[Colour Republic]

Has the room been tanked? is that the reason the first 4 foot is rendered?

 

[White Room]

Any lime should be remover if its flaking, there is not a magic solution to somethink.

A thinned down sbr can stabalize any powdery surfaces but not for strength

 

[Diamond Pool Finishers]

sounds to me like the first four foot is likely to have been damp-proofed m8, so be carfull

 

[jay]

would tend to agree with gooner best to re render area to be tiled using dampproof render if you can plaster prob would be easier if you use rock hard plaster (old style setting you trowl to glass finish) depends on your skill render could be left with float finish be my choice hope this helps:8:

 

[joe bloggs]

Has the room been tanked? is that the reason the first 4 foot is rendered?

My guess is that the following series of events took place before I moved here.

1. 1939, house was built (in a hurry I think) with separate adjoining bathroom and lavatory. The (South and West) concrete block walls, (made from mine waste round here, but that's another story) were plastered with lime plaster except for the area hidden by the iron bath. The plasterwork was painted.
2. Some time later the bath and basin were moved out, the plaster taken off to a height of 4' on both block walls of the bathroom and the bath and basin reinstated. At the bath head end (East wall, wood stud/iron mesh/lime plaster construction) the plaster and mesh were replaced with skimmed plasterboard to the same height as the render, packed out from the studs to make it level with the remaining lath and plaster. The whole bathroom was then tiled to the top of the roughly finished render and the rest painted or papered.
3. Later again the bathroom/Lavatory partition wall was removed, the lavatory doorway plasterboarded and the lavatory walls tilled. Possibly at this time an extra two rows of tiles were added to the enlarged bathroom, these tiles being above the render level.

So is it tanked? depends on your definition of tanking, but I'd say not, just a replacement of some plaster by a stronger render on part of the wall.

I'm removing any dodgy bits of lime plaster including all the top coat and am told that lime plaster is strong enough to hold the size of tiles I intend to fit, but would like to know that I'd done all I can to prepare the surface, including magic in a can, if its cost effective.

The more I think about this the more I feel like stripping it all off and rendering the lot. Good job the tiles haven't been chosen yet.

 

[Colour Republic]

Hi Joe

It is entirely possible that the property suffered from damp and it was common for the plaster to be hacked off and then was tanked with blackjack and rendered over.

The problem you have is that nobody could assure you that the lime plaster would be stable enough without seeing it first hand, as lime plaster does lose its strength over a period of time, even more so in a property that may have been subject to dampness in the past.

Judging by the pictures and what you have said, this room seems to have had many alterations over the years and has been patched up all over the place. I would think that it is time to bite the bullet and do an overhaul.

If it was me I would remove all lime plaster in the room and any other patched up areas. (Leave the render in situ) I would then put fresh plasterboard on all stud walls and then dot and dab fresh plasterboard onto the outside walls so it is flush with the existing render. Depending on what weight of tile you intend to install would then determine if the outside walls should be skimmed to give you a nice flat surface to tile on to.

Hope it helps

 

[joe bloggs]

Hi Joe
..................
If it was me I would remove all lime plaster in the room and any other patched up areas. (Leave the render in situ) I would then put fresh plasterboard on all stud walls and then dot and dab fresh plasterboard onto the outside walls so it is flush with the existing render. Depending on what weight of tile you intend to install would then determine if the outside walls should be skimmed to give you a nice flat surface to tile on to.

Hope it helps

a problem I have with dot and dab board idea is that the bath head end would need to have various holes and channels in it to fit concealed valves and pipework, would the dot and dabbed board retain its integrity when its essentially been cut in half with a big hole in the middle. I guess it will depend on how close together and where the 'dots' are. I assume that as the render goes up 4' I shan't need to tank it. 12.5mm board OK? 'moisture resistant board needed?
What is the relationship between the tile weight and need for skimming? I don't understand.

Alternatively I'm considering stripping off the lime and rendering both walls, something new for me to learn. I might practice on the garage first. If I use a 6/1/1 sand/cement/lime mix does it need any additive? should the blockwork just be wetted first?

sorry this is turning into a bit of a saga, but I really want these tiles to be a) flat and b) stay on the wall

compared to this plumbing the whole house pump and concealed valves is going to be a doddle, as is the new floor.

 

[Colour Republic]

Judging by the photos I am assuming the bath is going under the window with the longest side of the bath along the stud wall, is this right?

When you say concealed valves are you refering to a concealed shower valve or are you having a wall mounted bath mixer, are you saying where these valves and pipe work will be it is currently lime plaster and not render?

There are different tile weight limits for different types of substrate... i'll dig out the thread for you

 

[White Room]

Tiles and Adhesive Weight Per Square Metre - THE TILE SOURCE

 

[Colour Republic]

whoops, thanks Whitebeam I forgot about a link