Removing masonry paint from rendering

[Keefiedee]

Have googled this and not come up with any helpful answers - probably because there isn't one! No harm in asking here though if anyone has any suggestions. The original render is only about 20 years old, and is very flaky in places, so you think it would all be very happy to be scraped off. No such luck. Some of it comes off really easily and some just doesn't want to shift at all. Would it be safe to assume that the bits that don't want to come off will be happy to stay once repainted? I assume I will need to use stabiliser on the bare render

- is there any problem painting it over the bits of paint that won't come off.

Keith

[The Natural Philosopher]

yes. Pressure washer is likely a good way to remove anything that wants to come off, and not damage the render, assuming its in reasonable nick.

No need to use stabiliser. I didn't on fresh render. A piss coat was enough to seal it and I reckoned paint would stick to itself at least as well as to a stabiliser.

[Dave Liquorice]

doesn't

Confused, flakey render that is coming off in patches or are you refering to flaky paint on 20 year old render that is coming off in patches?

That's what I'm using to strip the paint off our exterior walls. Small domestic machine with a "dirt blaster" lance. Messy business though, even with tarpaulins down to collect most of the flakes I reckon there will still be white bits in the borders for years to come. Old water proofs a must and after a session I find bits of paint in many interesting places...

Agreed reading the instructions for the stabilsers they are for old, dusty, paint, rather than clean sound masonry/stone/render.

The first coat of paint I apply will be watered down a bit, in the hope it will get into smaller cracks and deeper than neat paint. The PW isn't getting all the paint off I may well quickly go over with a wire brush to make sure the bits that are still stuck are firmly stuck.

[Keefiedee]

Flaky paint coming off 20 year old render

Didn't realise that - somehow thought they were for render.

Thanks

[stuart noble]

They're for anything porous, which may include new render. The idea is to seal the surface so that the paint doesn't over penetrate. They used to be solvent based but I suppose that will have changed by now. IME watered down paint doesn't perform this function this very well. Cue argument about walls breathing....

[The Natural Philosopher]

Well it worked for me (piss coat: then full coats)

I'll neatly perform an arabesque and sidestep the argument over whether render is there to let the water out, or stop it getting in :-)

[Lino expert]

May I be the first to say....angle grinder.

[Frank Erskine]

Bravo!