Using exterior polyfilla to skim stonework?

[Rednadnerb]

Has anyone done this? I have been asked to paint the stonework on the front of a semi detached house that was previously covered with many layers of paint and has been stripped with back to the stone with chemicals.

The surface has been damaged all over by the paint removal and has an orange peel finish. The owner has told me he would like it to look like his neighbours which is in very good condition. To acheive this I would have to go over the whole surface with filler.

The deep holes and cracks I am ok with but spreading it like butter? I am not sure how long it would last. He has provided me with Polyfilla exterior filler, Toupret and some epoxy mortar (which says not to feather it).

Has anyone done this and regretted it? I am think of suggesting a couple of coats of masonry paint, electric sanding to smooth and then a coat to finish. Anyone tried that?

Thanks, Brendan.

[stuart noble]

Skimming with exterior filler works quite well on bare render, but you're probably looking at 25kg bags rather than retail sizes. Sounds like your customer needs a plasterer before a painter

[Rednadnerb]

Well, when I say skimming, I don't really mean laying it on 3mm thick, just enough to fill the pores then rub down. It's only the stone mullions around the windows at the front of the house so not a huge area.

I have a feeling that with no depth it would soon crack and peel underneath the paint. Anyone done it?

[mail]

Dear Brendan Personally, I would use SBR and VERY fine sand or ground stone particles as my filler Chris G

[stuart noble]

SBR is a bitch to use IME. I've used it in a cement slurry but, unlike pva, it doesn't really combine with anything very well. I'd go with the filler for this application.

[Rednadnerb]

Thanks Chris, that is a serious looking product but I don't think I like the waterproofing aspect of it for this application.

[Bruce]

The waterproofing aspect is desirable because it will help prevent frost damage to the filler.

[mail]

So what is the paint type? IF it is water proof then there is no loss I suppose it all depends on the porosity of the stone and whether or not it has some vapour porosity Given that it is due to be painted I would have suspected that SBR would not be a problem in most cases and after application it could be sanded to a smooth finish which would leave some original stone not pitted without SBR and in its natural state Chris G

[stuart noble]

I've used SBR in a cement slurry and it's not easy to sand. It's classed as a synthetic rubber after all.

[Dave Plowman (News)]

Exterior Polyfilla used to be a fine mortar but I think it's now something easier to sand so not so durable. I'd probably make my own using fine sand. Or a lime putty - although that will take a long time to dry before painting.

[mail]

Good point but with patience and good machines one can do it I accept it wont be a smooth transition from surface to pit but if done weak enought to just stick in the holes (which is where its wanted) I suspect from the sanding I have done with it incorporated into finish plaster you will get away with it One point I missed and that was to add some Portland cement to the fine sand/stone dust Mea culpa Chris G