Lime Plaster and Bathrooms

[Woody3]

Hi,

Is lime plaster compatible with bathrooms/wet rooms? A quick search didn't really provide anything conclusive.

We've just removed the not so gorgeous pampus green 1970's tiles from the bathroom walls (the bathroom was fully tiled) and have found that the plaster underneath is mainly gypsum with a few areas of lime.

There is one external wall (stone) that has 80% of "blown" lime plaster. We are undecided if to just strip the unusable plaster and repoint the stone work and limewash/leave exposed. Are there any reasons why this may be a bad idea?

The remaining three walls are internal and are of brick construction and are mainly gypsum plaster. We are hoping to get away with just having splash backs, with maybe one wall (behind the shower/bath) fully tiled.

Obviously "back in day", bathrooms didn't technically exist, so we just want to make sure if we remove the remaining gypsum and patch the room up with lime plaster, would it cope with:

1) The extra humidity of a bathroom

and

2) Wall Tiles.

Hope that all makes sense.

Cheers,

W.

 

[JohnB]

How about tadelakt?

http://canadianfamilyrobinson.com/tadelakt-shower/

 

[skier-hughes]

Our bathroom is 100% lime plastered, was done 12 months ago. No problem coping with my wife's long hot baths. We have a shower cubicle, and it has wetboards on it. Free standing bath so no tiling to the walls. No tiling (splashback) with sink yet, but this needs doing.
We used casein distemper to paint with, hardier than limewash.
After a real good hot bath you can see patches where the water has "soaked" in, but an hour later all looks the same again.

 

[MatthewC]

I had this sort of question over two years ago. I was replastering the bathroom entirely as it had been so damp so it was all done in lime. I realized that the breathability of the internal walls did not matter, so I tiled large areas of those for the bath and shower. Then I tiled smaller areas near the loo and washbasin which were against the external wall, reasoning that the wall will still breathe but not as well. On the bare plaster I used breathable emulsion which I think was NBT Trade Emulsion from Mike Wye.

The key thing was to make sure there is a good extractor fan and that it has been installed properly. Mine didn't, so I checked on my electrician's lad and found that above the ceiling he had used a huge length of flexible hose rather than cut it, with the result that the fan couldn't push the air hard enough to work.

Since then it's not been a problem - the walls get damp but they dry out fairly quickly, but I do always leave the bathroom door open after a shower to help the drying process.

 

[Woody3]

Thanks for the replies chaps.

We will definitely lime plaster the external wall.

Did you find it ok to tile straight onto lime plaster? Any special adhesive required?

We were hoping not to have an extractor fan. I think we'll see how we get on with just opening the window and if needs be, install one at a later date.

Thanks again,

W.

 

[MatthewC]

Thanks for the replies chaps.

We will definitely lime plaster the external wall.

Did you find it ok to tile straight onto lime plaster? Any special adhesive required?

We were hoping not to have an extractor fan. I think we'll see how we get on with just opening the window and if needs be, install one at a later date.

Thanks again,

W.

I used ordinary tile adhesive directly to the unpainted lime plaster and the tiles are all still attached (unlike the ones in the new extension which has gypsum plaster!).

 

[skier-hughes]

We have tiles on the casein distemper suing normal tile adhesive and all ok as a splash back in the en-suite.
We don't have a fan in either en-suite or bathroom and rely on opening doors and windows which is plenty.

 

[Woody3]

Thanks chaps.

I'm lime plastering the lot then.

What strength NHL did you all use? Is NHL2 strong enough, or would 3.5 be better (I've got 5 bags of 3.5 left over from repointing that's all and don't want them to go to waste!)?

 

[skier-hughes]

I had plasterers in to do it, and they said I could pay them to mix it up or I could just buy it ready mixed, probably cheaper, so I bought ready mixed
http://www.lime.org.uk/products/mortars-and-plasters/lime-plasters/
Base coat with hair and top coat.
NHL isn't the best for plastering