Masonary Paint Removal

[Dave Liquorice]

Need to repaint the outside of the house, the old masonary paint is flaking off, though some bits are still sound. Manually scraping or wire brushing two windowless, 8m wide, two storey gable ends and another 10m wall doesn't appeal...

I'm thinking that a compressed air driven needle gun is the way to go but not sure how vicious (or not) such a device is. The substrate is stone and the pointing may well need looking at and chasing out in places before repainting.

So is the needle gun a good idea or is there something better out there?

[Tim Watts]

On Tue, 15 Jun 2010 14:18:08 +0100, "Dave Liquorice" wibbled:

Would a pressure washer work?

[js.b1]

A pressure washer can be fitted with a sand blaster attachment. That may be too severe, or at least risks brick face damage.

However I'm sure Tommy Walsh had an angle grinder (looked like 9") with a large flat disc with a pad on it which was specifically to remove paint without damaging the face of bricks. Once the face has gone you are screwed, a few wet winters will trash them quite quickly.

The material on the disk was arranged in a raised spiral pattern, I suspect not too different to a 3M Clean n Strip disc - but much harder because they wear down very quickly when removing even small paint spots from brickwork.

[stuart noble]

I took mine off a rendered surface with paint stripper (generic brand from a trade outlet rather than the Nitromors). Took about 15 litres IIRC. Piece of cake if the wall is flat. Forget it otherwise.

[Phil L]

They're stones, not bricks.

Having it professionally blasted would be ideal but as you can imagine this is going to be expensive. manually with a wire brush is going to take forever. Which leaves mechanically, and doing it with a needle gun wouldn't work neither IME as I think the needles would just compress spots of paint into the stone.

a grit blaster /pressure washer and can be had for about £50 a week, although I'd be a bit wary of water ingress, especially if it requires repointing in places

[The Medway Handyman]

Even a big bugger would only take the flakey stuff off.

[Tim Watts]

On Tue, 15 Jun 2010 18:31:18 +0100, "The Medway Handyman" wibbled:

Isn't that's all that's needed - he's repainting it?

As you're the man, can you get extra long lances on the for-hire big machines for this sort of job?

I live in an old bolloxed house, but at least the walls aren't rendered or painted - I think that's one job I'd hate more than anything...

[newshound]

I've used a needle gun on mine, but of course it doesn't do a very big area. Good for getting off the stuff that's a bit flakey but won't actually fall off. To my mind, if the gun won't take it off you can paint over it. It's also not bad for digging into some of the irregular pointing on my random stone, if that's what you have. I'm repointing with lime mortar and painting with home made lime wash.

[Lobster]

I'd say so - I originally bought my pressure washer for exactly this purpose (crappy masonry old paint over crappy older pebbledash). TBH the pressure washer was too powerful in that it tended to bring off the render too... cearly that's shot and ideally wants redoing; however pressure wash/stabiliser/Sandtex treatment worked miracles.

David

[The Medway Handyman]

Fixed lances go to about 2m. You can get telescopic lances up to 7.2m

do take a bit of hanging on to :-)

Doubt if many hire shops would have them though.

[Dave Liquorice]

I'd like to get as much of the old layers of paint of as possible so I can clean/stabilise the stone, repoint as required and apply a modern breathable paint. By "old" I would guesstimate at 20 or 30 years and it's those old layers that are failing.

There is fair bit of kick from a normal short lance ona domestic washer let along a BFO one with a long lance. You wouldn't be able to see what you are doing either.

Render I hate, I always feel it's there to cover up a problem with the wall. Last winter a great slab of it fell off one wall, base coat is pretty soft with a hard thin layer. Who ever put it on didn't remove the existing paint, that paint has now failed thus the render has fallen off... I shall probably remove all that render as the rest of the wall is bound to go the same way.

[Dave Liquorice]

Mixture of pebble dash, render but with a coarse sand surface and random stone. Definately not flat and SWMBO'd would object to nasty chemicals getting anywhere near the borders...

[Tim Watts]

On Wed, 16 Jun 2010 09:49:53 +0100, "Dave Liquorice" wibbled:

Fair enough - I would want to do the same now I understand what you have.

How about paint stripper then pressure washing?

I was just thinking hanging off a ladder with a pressure washer lance with crap flying everywhere might be a bit dicey - or do you have a tower/ scaffold?

[Dave Liquorice]

If used straight on I can see that being a possibilty but when used at an angle and the needles worn into lots of little chisels?

Interesting, thanks for the link. I think you'd need to add the hire of a suitable PW onto that =A350/week though. As there is quite a bit of "growth" behind the flaky paint a good wash down of the wall is something that will have to happen anyway.

Ha, we get proper wet up here driven by storm force winds... not quite the same as a PW but a lot more than most buildings get exposed to.

[Lobster]

PS - something else I thought of - *against* the idea of using a pressure washer: when I did our house, the entire garden (probably the neighbours' too) was filled with flakes of white. It went everywhere, all over the flowerbeds too, and probably took about a year or two until all traces had finally disappeared. *She* was not a happy bunny.

David

[The Natural Philosopher]

Mmm. try a pressure washer straight then.

Of possibly industrial grade

It will certainly rip loose flakes off, and general crud.

You make need to get close in with a domestic sort. Will take a long time.

If the surface is that rough anyway, you really don't care about a smooth finish: just removing the flaky is all you want.

[The Natural Philosopher]

But that is really all that is needed. Te issue is to remove stuff that would likely fall off anyway, then the new pain will fill all the gaps that are left.

In essence all you want to do is hit the paint harder than the wind and weather will in the future. Pressure washer is perfect for that.

[The Natural Philosopher]

No, sometimes its part of the intended structure of the house.

Last winter a great slab of it fell off one wall, base coat

Ah well, mine is all laid over metal lathe, and painted to the hilt. Lovely.

[Lobster]

Which will be as nothing compared to the time the painting is going to take. Painting fresh pebbledash/Tyrolean render is one of the most tedious jobs I've ever had to do.

David

[<me9]

Even worse than fresh spiky artex?