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We have stone windowsills and vertical bits (mullions?) which have a million layers of paint on. It's all flaking off now and I want to strip them back and repaint.
I did the ones at the back with a scraper but they had fewer layers and it still took forever. That was only sills as well so a lot smaller area than the front.
I've googled and everything seems to suggest chemicals are the best option but I doubt they would deal with however many layers of paint there is. Would a knotted wire brush on an angle grinder do the job?
I'm not overly arsed about a bit of potential damage to the stone as we have the house up for sale anyway. I just really can't be bothered scraping it all off.
Would a knotted wire brush on an angle grinder do the job?
Oh yeah. In fact wire wheel on angle grinder takes off just about anything. It will be pretty aggressive so a light touch is the order of the day. Though after a bit of use you'll be able to judge it as to pressure.
Be careful, last thing you want to catch in it is your jumper 😉
I'd consider heating it with a heat gun. Or maybe even steaming it off. It may soften and peal off with either of those two.
I thoroughly recomend this. We have a gnarly old stone staircase that had a million coats of old noxious paint on. That stuff got it all of easilly. Heating it could cause it to melt into the stone and be evem harder to get off.
Yeah I'm wary of using heat as I know it could just make it worse, plus I don't want to get heat too close to the uPVC window frames.
I've seen that peelaway stuff but it's at the more expensive end of the getting stuff done spectrum. Especially compared to an 8 quid wire brush for the grinder.
Ah cool, thought Peelaway had been banned!
Used it about 15 years ago for a million coats of paint staircase, worked a treat.
You need to hire/buy a needlegun scaler for that.
@northernmatt yeah Peelaway is relatively expensive but it depends on how big a surface area you need to do. We got 1 x 15kg tub and it did the staircase, a big beam and a few other wood/stone features around the house.
Paint removal is a large part of my job (stone mason)
Most effective method is “tooling off”, basically removing 2-3mm from the stone to remove paint. This also removes the hard callus that has built up as well leaving the rest to be basically sanded back. Leaves the building looking fresh! Peel away still gets used a lot but I don’t like it as it doesn’t remove everything and the stone will still need work after using peel away.
There are various pressure washing systems used to some effect. DOFF- steam based pressure washer system and TORQ- kind of fine aggregate in water. Don’t know if you would be able to get your hands on them though.
Please avoid the wire brush on a drill/grinder. It will likely do more harm than good. Probably leaving everything looking swirly!
What stone is it? Or where are you based? These answers may change the method!
That was a very brief summary! Message if you need any thing else
As a side note paint removal is often two jobs in a way. First remove the paint then asses the damage/problems left behind and sort them out. Just be aware paint often hides things that will have to deal with down the line!
Can you confirm if it is a problem after you roughly grind/sand/chip away the outer layer, that this can cause problems with degradation of the stone surface, and its required you to put some sort of coating on it or to polish it to make it weatherproof.
Havent a clue myself, but i do remember reading something about it.
On a garden wall, I used a wire brush drill attachment to get rid of anything loose.. Gently just to get rid of of anything flakey.
Then a few coats of stablalisier solution
EverBuild 406 Stabilising Solution 5 Litre https://amzn.eu/d/ekPI2Ad
And then just painted over it with masonry paint.
Dunno it that's the best thing to do but it turned out fine and seems solid.
@marksnook I'm honestly not sure what stone it is. It's a late 1800s terraced cottage in Sunderland. The ones at the back just came up looking grey-ish.
I'll be painting again once it's cleaned so swirly patterns may not be an issue. If I just take the flaky stuff off and throw more paint on it'll look terrible because of how thick the existing paint is.
@dyna-ti once paint has been removed we don’t apply anything. If tooling off the stone is down to a “new” looking area (probably an awkward way to describe it!) we just leave that to form a callus which sort of protects itself.
The problem with coatings and paint or sealers is that it can trap moisture. The moisture can then freeze, the expansion of water freezing often makes the stone crack/blow. Also damp/water can’t escape if it’s sealed in. I think it’s bad practice to seal/paint. Lime wash is the best method of painting as it does allow moisture to leave the stone
I’m southwest based and limestone (bath) is largely what we are doing this on. Processes could be different for other stone types
@northernmatt you could use some sort of chemical stripper then pressure wash it if you aren’t sure of the stone? Or maybe ask a local masonry company?
What about CO2 blasting? We have one at work for cleaning machinery - the blasting effect works by 'catching an edge' of the substrate/paint/stuff you want cleaning off coupled with the explosive nature of the CO2 pellet hitting something. It won't piss your neighbors off like sand blasting does and isn't aggressive to the substrate.
However - not sure on costs of it due to massive rise in CO2 costs recently.
Not sure on CO2 blasting - there is place in Middlesbrough but they seem to lean to industrial stuff from their website. Don't want to go the shotblasting route due to the mess. I think I'll grab a knotted brush at the weekend and test it on a small area to see what it's like. If it looks shite I can always bite the bullet and get that Peelaway stuff.
I had mine sandblasted - I wish I hadn't; lots of damage and crap everywhere
@dyna-ti once paint has been removed we don’t apply anything. If tooling off the stone is down to a “new” looking area (probably an awkward way to describe it!) we just leave that to form a callus which sort of protects itself.
The problem with coatings and paint or sealers is that it can trap moisture. The moisture can then freeze, the expansion of water freezing often makes the stone crack/blow. Also damp/water can’t escape if it’s sealed in. I think it’s bad practice to seal/paint. Lime wash is the best method of painting as it does allow moisture to leave the stoneI’m southwest based and limestone (bath) is largely what we are doing this on. Processes could be different for other stone types
I'm in the same line of work as marksnook and agree with this.
If you are contemplating jetwashing be very cautious - I am generally working with sandstones here in Scotland and it is very easy to cut through some of the softer stones with even low pressures(ask me how I know). Wire brushes can also cause a lot of damage so go easy!