Emergency lime plaster repair - help please

[sarahj]

Hi,

I have a week to decorate my 6 year old daughter's bedroom. I have emptied it, taken up the carpets, and the fun bit: pulling off the wallpaper - it came off in sheets, all of it!. However, a small area directly under the very low window ledge pulled off the plaster as well - right down to the stone. It is an area of about 18" by 18", and is the outside wall. (Sadly all of the other walls are modern gypsum).

I would very much like to patch this with ready made lime plaster - can I buy it from builders merchants and will I be able to do it along with the rest of the wallpapering?

I currently have her camped down in our bedroom while my husband is away for the week and the room is so small there is not really the space to do it on his return (we would both have to climb over her to get to our bed!)

I live in rural Northumberland so on the one hand I would expect local builders merchants to understand and supply lime products but on the other hand I expect that if they do local builders probably mix their own from scratch.

Thank you,

Sarah

 

[skier-hughes]

How deep is your plaster?
I suspect you'll not be able to do it in a week if you want a proper and lasting repair.
YOu'd need a first coat of haired plaster, this would be kept dampish for a week, you'd then add another coat, damp for a week and then your top coat.
I've not papered over lime plaster, but I doubt you'd be able to paper over this top coat for several weeks as it dried out properly.
You can buy ready prepared haired plaster and top coat, but I'm not sure how many normal builders merchants will stock it, you may need to get it delivered from one of the specialists.

 

[sarahj]

HI,

Thank you, I thought as much. I wouldn't be papering over the lime plaster, either, if it wasn't full of patches of lime, gypsum and filler, and thus would look horrid painted over especially with limewash and I don't want to use modern emulsion on it. At least the lining paper would be a little breathable! It's such a small bedroom (one of those L shaped ones over the stairs) that we would have to keep her out of it until the wall was done. I am getting quite stressed now, over what was going to be a nice little one week job (I don't know why I thought this as our house has had everything botched several times over and nothing has ever been a nice little job) - lifting the carpet showed that the drop in the corner (Oh, I always thought, how quaint) was actually new floorboards nailed to old beams without building up the beam in the corner, and there is a ridge half way along the floor near the skirting board where the end of the floor board sticks up which isn't going to be very good for laying the carpet. Neither is the two inch gap in the other corner where there is no floorboard and you can see into the sitting room etc etc. Why did I start this!

I've just rung a conservation-prize-winning builder for a quote on remedial damp works (we have an underground one and a half storey two hundred year old wall) and the first thing he said was 'rising damp?' Noooooo!

 

[Nigel Watts]

The easiest way to make the repair is to buy ready-made lime plaster in a tub but only highly specialist merchants will stock pre-mixed lime (I live in North London and ordered mine from Devon).

The next easiest is to make some yourself from lime putty and sand. Tubs of putty are also quite hard to find but are more readily available than premixed lime plasters (I found some in South London). A tub has infinite shelf life so long as the putty is under water and the lid kept on securely. The advantage of this method is that you can create a different mix for the backing coat and the finish coat. If you are plastering onto stone I would say that hair is not essential. It would be for plastering over laths.

The backing coat should be about 3 parts sand to 1 of lime and sand can be of a fairly coarse variety. Dampen the stone well before applying and score the surface before it hardens to give a key for the next coat. It should be allowed to dry slowly, for about a week. Finish coat should be more like 2 sand to 1 putty, or even 3 to 2, using a fine silver sand. Again, dampen well first and allow to dry slowly. Ideally you should wait six months or so before papering over.

 

[JohnB]

Could you do what we discussed in this topic, and cover part of the wall with wood panelling with an air gap behind? It could be done quickly, and is easily removed if/when you have the time to do the job properly. Or cover the area with shelving, built in furniture or something, again making sure there is ventilation.