Spouse has been asked to paint a neighbour's back room. It's in a bad and filthy condition (don't ask) but one patch of about an irregular square yard has a damp-affected decorative surface.
It's the original applied surface from the 1930s, a low-relief 'combed' shell effect which is on all walls and continues over the ceiling. It's not Artex and not Anaglypta - there are no seams.
Spouse says that it feels like some kind of plastic.
Does anyone know what it could be and how the patch could effectively be repaired to blend in with the rest of the room? The decorator the neighbour called in originally said the only way to hide it was by plasterboard ... not an ideal solution!
It wasn't uncommon until the 50's to varnish painted walls - this often gives a plastic like surface. If the room has had many coats of paint over time and open fires and/or heavy smokers this can also produce a hard plastic like skin of oils and tars. Oil bound distemper gives a similar effect.
The original plaster would probably have been a base of half an inch of hair mortar (3 parts sand, 1 of lime mixed to stiff paste and a handful of soft chopped hair or fibre per bucketload added). For more rapid setting in repair work Plaster of Paris would have been added (one part of Plaster of Paris to 8 parts of mortar mix and water to taste).
The second, floating coat, would be the true levelling coat and about a quarter to three eighths of an inch in depth. This would be mortar as above but sometimes without the hair. The final finishing or skimming coat would be one part slaked lime to one part Plaster of Paris to two parts fine sieved sand and about a tenth of an inch in depth.
I would guess the second or final coat have been patterned and then painted with an oil distemper or oil paint/varnish.
You should be able to repair it with modern plasters (after solving the damp problem obviously, lime based plaster such as Limelite from Tilcon or those found at the url at the bottom would be the closest to the original and stands damp well.
Matching the pattern will be a challenge - possibly some experiments with home made patterning tools/notched trowels and plaster on some old wooden sheets first would be worthwhile.
Getting the same surface feel probably means emulating a significant thickness of paint but should be possible by applying several coats of thick oil based paint (or possibly gloss or eggshell finish water based paints). I presume exact colour matching is unimportant as the whole room is to be repainted.
The whole process will probably take several weeks however as various stages need to dry thoroughly.
Yes but this definitely has a textured, regular patterned surface.
That's already gone.
I'll have a look, thank you very much.
Spouse is a man of many talents :-)
Well, to be frank, the whole thing is unimportant. The neighbour doesn't care (but doesn't want to pay for plasterboard!) It doesn't have to be a perfect result for her, she wouldn't see it. Spouse wants to do the best for his own satisfaction. We still think that it was something other than a simple plaster finish though ...
Well, I don't think it will contain asbestos, it's not a building material, i.e. part of the construction. It's a finish, pure and simple. Much like Artex but more flexible. It will peel off like painted paper - but it isn't painted paper. But with all older buildings it's a good thing to be wary of the possibility of presence of loose asbestos.
there isnt anything cheaper to fill an area of plaster in with... mud? Food leftovers? If your customer isnt even willing to pay =A33 for the absolutely chpeast material...
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