Cleaning Brickwork prior to applying Stormdry

[opps]

My mate, Colin the Pointer, uses hydrofluoric acid. He wets the bricks, brushes it on and then uses a pressure washer.

HF20 – Code 30

Specially formulated gelled, hydrofluoric acid cleaner to cope with the difficult cleaning problems encountered when cleaning siliceous masonry on old buildings.

chela.co.uk

I believe it is a trade only product. And you definitely have to use the proper PPE

 

[Ivor Windybottom]

I'm pretty sure you'd need a full grind-out and repoint after that stuff's dissolved the cement away.

 

[opps]

I'm pretty sure you'd need a full grind-out and repoint after that stuff's dissolved the cement away.

Agreed, it may well damage the pointing. I should have mentioned that he uses the hydrofluoric acid prior to then racking out the pointing.

I don't think it does though. I need to ask him when I see him next.

From memory, he has used it on walls that did not require repointing (red rubber bricks).

When pointing red rubber bricks with lime mortar, he uses hydrochloric acid (brick acid) to remove the smudges. I doesn't damage the new pointing but it will slightly change the colour of it.

 

[noseall]

I'm pretty sure you'd need a full grind-out and repoint after that stuff's dissolved the cement away.

Most brick cleaning solutions are only active of a short time, before the solution neutralises. That said, a nice crisp smoothly struck pointing surface, will become etched. It's a bit like aging the pointing by about 3 years, each time you apply a coat.