Reply With QuoteOne thing I was advised is that stabilising solution isn't breathable, so applying it to damp wall traps the moisture in. Sandtex is a very good product and I'd suggest contact their advice department who'd be able to answer your questions.
R
Just looking for some advice on external masonry paint products and the required preparation before decorating.
Firstly the preparations side of things.
I live in a 1930’s-built house and the external walls consist of brickwork, no cavity with pebble dash render (previously painted). I have a few areas of penetrating damp that is staining the internal plaster finish and having reviewed the render adjacent it appears there are a number of hairline cracks, so I assume this is the cause of water ingress, causing the damp staining.
The hairline cracks are all so fine I will not be able to press any filler into the crack and the pebble dash finish makes this even harder to achieve. Would these cracks need to be grinded out and then filled before decorating?
The existing paint has perished in areas and has exposed the render with spot areas of mould growth. Would this need to be cleaned with fungical wash? Due to the paint finish being poor would it then also need a stabilising solution?
Secondly, the paint I can apply.
The product previously used to decorate the render was Johnstone’s Trade Stormshield Pliolite based masonry finish. This is a solvent (oil) based paint.
I am not sure how breathable solvent based paints are, or if they are breathable at all. This is why I would like to apply a water based paint (Sandtex).
Please can advise be provided, if I can apply a water-based paint on to a weathered solvent-based paint (I have heard people say this can cause an issue and is not recommended). I know a water-based paint can be applied onto a water based paint and Solvent based paint onto water based paint.
Any advice or feedback from someone in the know would be appreciated.
One thing I was advised is that stabilising solution isn't breathable, so applying it to damp wall traps the moisture in. Sandtex is a very good product and I'd suggest contact their advice department who'd be able to answer your questions.
R
Last edited by ralphy; 12th February 2023 at 23:43.
Ignorance breeds Fear. Fear breeds Hatred. Hatred breeds Ignorance. Break the chain.
Just seen your in Bristol, not a million miles down the road in Weston super mare there is WDS https://www.winterstokedecorators.co.uk/ give them a call on the paint and ask there advice, I used to buy paint wholesale from them a few years back and the knowledge and advice was always top notch and when they didn't know they would call back, I'd suspect it would be sandtex but maybe wrong.
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Definitely worth seeking more advice on the oil based/water based situation.
Have a look at Bedec paints. I was advised to use their masonry paint on old render which had hairline cracks in. You can have the colour matched to pretty much anything. It still looks good five years on, just wish we still lived in the house
Are the gutters and drain pipes all in good condition? Are the damp patches adjacent to any chimney breasts? I assume you've ruled out condensation? Hairline cracks in render wouldn't immediately spring to mind as the cause of penetrating damp.
All the gutters and down pipes are in good condition and not leaking. Damp patches are located away from chimney breasts and I don’t expect it to be condensation because all clothes are dried in the tumble dryer and I have a dehumidifier that I use occasionally to keep the relative humidity down.Originally Posted by hogthrob
I didn’t think hairline cracking would be cause initially but it’s the only visible sign I can see that would let rainwater enter the property.
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