filling gaps in plaster

[Mark D Smith]

Hi

following the removal of some woodchip i have revealed a 1" wide by 10" long full depth break in the old 100yr+ plaster. it goes back to the brickwork. either side seems solid so i am wanting to just fill and sand it to make good. what is best method to repair it. ultimately it will be papered over.

Mark

[TonyB]

From a previous post - papier mache?

TonyB

[Andrew Gabriel]

Firstly, I assume the brickwork behind is dry. If it isn't, post again and we can discuss some other options.

If you are not familiar with using plaster, then polyfilla is probably the easiest to use. If the existing plaster is crumbly or easily sheds particles from the exposed edge (i.e. lime plaster), I would start by painting the edge with plenty of diluted PVA (1 part PVA to 5 parts water) which will soak in and stabalise the exposed edge, and also help prevent it coming away from the brickwork. Then mix up polyfilla and put it in the hole. Given the large area of the hole, I would do this in at least 2 goes, the first still leaving the polyfilla surface 2-5mm below the plaster surface, and when this has set, do a second thinner coat which is much easier to finish off level with the plaster, without slumping, and without the need for any sanding afterwards.

[Mark D Smith]

Hi Andrew

brickwork is dry. i think PVA wash is the first step as the old edges are a bit crumbly. have used polyfilla before but i always got that slumping. guess i tried to fill too much at once.

thanks for tips.

Mark

[William Gould]

yeah sounds good.... i used watered down pva to seal and then pre-mixed bonding plaster from Wickes to fill gaps in 100+ year old 'horsehair plaster'. I then finised off with a fine ultra lightweight filler... results were excellent after a few rub downs.

Cheers.

Will.