Painted Portland stone

[brittas2009]

I have a 1930's house with a bay window at the front. The brickwork above and below the bay has Portland stone 'corners'.

The previous owners have at some point painted the stone with White Emulsion, which over the years have flaked and looks a complete mess.

I wanted to bring the stone back to a natural clean surface. I've used a pressure washer with detergent and also had a go with a wire brush drill attachment. It's better than it was but there are still large areas where the paint just won't shift, especially where the stone is pitted with erosion.

Someone recommended I use brick acid to clean it, but I'm a bit nervous about using it - would it be too corrosive?

I'd be really grateful of any advice, thanks!

 

[SUPERSLASHER]

If you get a steam cleaner it will lift the paint from the stonework without damaging it. Do not use brick acid on real stone. S/S

 

[noseall]

brick acid (hydrochloric acid) reacts with cement or lime based products.

as far as mortar goes, it neutralises the effect of the cement thus turning the mortar back to sand.

if your stone work is say sandstone, granite or flint then don't worry. but do be aware it may affect the mortar joints.

if it is limestone......

 

[stuart45]

Unfortunately Portland stone is limestone.

 

[noseall]

The brickwork above and below the bay has Portland stone 'corners'.

oh, yeah. no acid.