keeping old lime plaster

[sarahj]

I habve just had a moment of madness and pulled all of the thick textured wallpaper (emulsioned of course) off the external walls of our bedroom. The internal walls are relatively modern partition walls so I haven't touched those yet. Last summer we had our stone built cottage repointed in lime and the tatty plastic guttering (that was falling off an inappropriate fascia board that was also falling off) replaced with cast iron.

Now that no more damp is coming through, I thought it was about time i exposed what was well hidden underneath the hideous wall covering painted in 'cappuchino' (old tin discovered in garage) which is more like 'gypsum pink'.

Most of the plaster is surprisingly fairly sound. There are plenty of cracks, but no holes and nothing falling off, although there are some hollow sounds in places when you tap it. A very small amount of gypsum patching on the fireplace and where an electrical socket was fitted above the skirting board.

How do i fill the cracks, and which is better for a bedroom wall - distemper or limewash, and will it be ok to use f&b cos I'm on a really tight budget at the moment and I'm likely to be doing one wall at a time and buy8ing one tin of paint at a time!.

Problem bits are a window that appears to have a history of damp because its sill is so close to the adjoining garage roof: this has all been sealed up with lime mortar on the outside, but on the inside someone has cemented (it doesn't even look like plaster) over the whole width and depth under the window, and then covered it in a brown varnish like substance which is also on the inside of the window recess.

Should I attempt to remove this cement? and how do I get rid of the varnish applied to the lime plaster?

 

[Gervase]

You can fill the cracks with ordinary filler out of the box. Or you could use a mix of 1:1 hydrated lime and silver sand. Don't worry about a few hollow sounding areas - unless the plaster has blown enough to flex when you press it and to crack, then a bit of hollowness is fine.
As for finish, distemper and limewash are both fine for the walls, though limewash is more likely to rub off onto clothes. Either way, it will be cheaper to make your own rather than pay F&Bs high prices (and their limewash is not very good, in my experience). You can pigment your wash or distemper either with natural pigments of the sort available from Ty Mawr and the green building outlets, or with simple powder pigments used for making poster paint, or even raddle powder for sheep - Netex do a great blue powder which makes a lovely azure limewash; a perfect match for the old-fashioned blue used on kitchen and pantry ceilings as a fly deterrent.
If you want to use ready-made, I'd recommend Rose of Jericho rather than F&B.
The cement under the window could just be a surface patch or it could go deeper than that (literally), If the window has been replaced in the past, it's possible that some of the stonework under the sill was dislodged and then held back together with cement. Removing the cement may also entail removing the stonework under the window, which would then require replacement - not a major job, but a bit more than just repointing.
The varnish may be soluble in Nitromors or a similar alkaline stripper. Don't use anything acidic, as this will destroy the mortar.

 

[Penners]

with simple powder pigments used for making poster paint, or even raddle powder for sheep

A great conversation piece - everyone will wonder what the ram's being doing to your wall.

 

[Jane Smith]

In your case, Penners, I can imagine. Sadly.

 

[ajbaker]

sarahj

You are just embarking on a very similar process that I am almost completing. When I removed the wallpaper in my bedroom the plaster was perhaps in a slightly worse condition than you describe. That any my desire to practice my lime plastering 'skills' (one day course!) led me to replaster. I have however gone through the same thought processes regarding surface finish...

I would have preferred to use a limewash, but sadly the room is quite small and I always brush against the wall when moving in the room. Therefore this had to be avoided as it does brush onto clothes. If your room is fairly large you may get away with it. It is possible to add linseed oil and casein (semi-skimmed milk from that I can gather) to the limewash to reduce the chalkiness.

I have no experience with distemper. Again from what I can gather this does brush off also, but to a lesser degree. I will probably try this in the future.

Another possibility, and the option I chose was a breathable paint. I chose one from Natural Building Technologies (NBT). A really lovely finish, but you do lose some of the advantages of limewash: the wonderful depth of colour among other things. It is however wipeable and does not brush off.

If you are pressed for finance at the moment consider a limewash for the time being; you can always add something else on top. A tub of lime putty costs around £5, add water, stir for ages (!) and you have will have more limewash than you know what to do with. Far cheaper than F&B. There are a few suppliers of lime putty. Where are you?

 

[L1zzy]

Hi I can help - I can heartily recommend Rose of Jericho Distemper (no it doesn't come off easily in fact when I used it not at all.) Peter Ellis at Rof J is a really helpful chap as well and if ever I've emailed he's replied same day. I am about to order Pale Yellow Ochre Distemper to do all my walls. After experimenting with pigments (also from Rof J) I've decided their ready mixed distemper is too good to miss. and I could fiddle around for ever trying to get teh colour I'm after. I used one of their samples initially and although its a tad tricky distempering on your own you need to keep a wet edge to your work) and you need to work fast the resulting soft,deep colour is gloriously velvety to touch - I'll never go back to modern paints now even if they are F&B! Be aware distemper doesn't keep - it goes sour in about 12 days if you don't use it. happy painting!!

 

[L1zzy]

Netex do a great blue powder which makes a lovely azure limewash; a perfect match for the old-fashioned blue used on kitchen and pantry ceilings as a fly deterrent.

Gervase can you give me some contact ino on Netex only I can't find on I/N.

Ta

 

[Nemesis]

The blue - it wasn't the colour apparently, it was the chemical which produced the blue the flies didn't like.

 

[Gervase]

I get the raddle powder from my local farmer's co-op here in West Wales, but a quick Google brings up: http://www.farmrite.co.uk/category.ds2?c=343 ta-dah smiley inserted

 

[Gervase]

The blue - it wasn't the colour apparently, it was the chemical which produced the blue the flies didn't like.

Don't you go coming over all scientific with me, madam. I'm sticking to the aesthetic argument - "Bzzz, either that paint goes or I do..."

 

[NT]

Distemper does not rub off, I know because I've lived with it for many years. I gather it was the standard interoir paint before smulsion came along.

It is entirely possible for incorrectly homemade paints to produce borderline results of course, but decent distemper has no such problem.


NT

 

[Penners]

Be aware distemper doesn't keep - it goes sour in about 12 days if you don't use it.

You're supposed to slosh it on the walls, not drink it.

 

[michael]

Sarahj with regard to the paint finish you should refer to my discussion on Classidur - an alternative to limewash? Just enter the word "classidur" in the search box to find it.
In trying to find the best paint finish for my particular application where I have a number of different surfaces to coat including old and new horeshair lime, modern gypsum and emulsion coated surfaces, I considered and discussed a number of options on this site from "Classidur", a very expensive breathable paint from Switzerland right down to a very cheap Contract trade emulsion. The later emulsion product was recomendedto me by The SPBA as the cheapest and most effective multi surface breathable paint and this was apparently decided by the Traditional Paint Forum founded by Colin Mitchell Rose. I did listen to peoples advice on Limewash and distemper all of which are commented on in the above discussion. My understanding is that:
DISTEMPER even with the various additives can still rub off even more so than limewash. Distemper it would seem is more suited to ceilings and ceiling details. I also understand that some of the additives can reduce the breathability and can also support mould growth.
LIMEWASH apparently needs water and vigorous rubbing to remove.If your walls were entirely lime plastered then I would have gone for the limewash option. As your walls are a mishmash of materials it may be worth considering some of the specialist pigment paints, clay paints etc however advice couldnt be given on these by the SPBA as they felt that they hadnt been fully tried and tested over a long period of time.
If you're strapped for cash then I'm sure you wont go wrong by using the cheap and cheerful, breathable,SPBA recommended Contract Trade Emulsion.

 

[michael]

P.S I think distemper rubs off only if theres moisture involved e.g with a wetted finger.

 

[Gervase]

if you want a finish that is breathable but which doesn't rub off, try an oil-bound distemper. These use a gelatine and linseed oil binder rather than the water-soluble protein binders used in ordinary distemper.
For a good overview of the types of natural paint, have a look at Rose of Jericho's sheet here and the data specs here.

 

[stickybeak]

Blue tints:
You need to be a bit careful when adding blue to limewash- it has a very short useful life of just a few hours as the alkali tends to 'bleach' the colour very quickly, so mix it and use it without delay. (from a Rory Young session via SPAB).

Saponification:
You also need to be careful when limewashing a freshly lime-rendered wall as the addition of all but a tiny proportion of any oily substance may lead to saponification, i.e. the oil reacts with the alkali in the lime render/plaster to produce a 'soapy' surface which can then mildew and go black. It is recommended by them wot knows to leave a freshly rendered/pastered wall for at least three months and sometimes a year or more to ensure that the lime has properly cured before coating with an oil-based paint, even a doctored limewash. Nothing to stop you limewashing first and then waiting some time to put on an oil-based topcoat of course.