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.

 

[John74813]

Ok so the conensus is to leave the Stormdry to when it's warmer weather. While the scaffolding is still up though I hope to clean the bricks. Is everyone in agreement this is the right method? https://www.amazon.co.uk/dp/B0087YSTBI (Feb Brickclean External Brick Cleaner | Cleaning and Deagreasing Solution for Brick, Concrete and Stone Surfaces)

I'm a bit anxious about messing it up / damaging the mortar or something. I contacted a local handyman who suggested a render cleaner which clears off algae and lichen. Spray it on, wait 15mins then rinse it off. Problem is I've already tried this: https://www.amazon.co.uk/Spear-Jackson-Spray-Concentrated-Remover/dp/B011KT373Q?th=1 (Spear & Jackson - Spray and Leave Concentrated Mould, Algae and Lichen Remover) and it doesn't seem to have done anything!! Not really sure what to do

 

[noseall]

Ok so the conensus is to leave the Stormdry to when it's warmer weather. While the scaffolding is still up though I hope to clean the bricks. Is everyone in agreement this is the right method? https://www.amazon.co.uk/dp/B0087YSTBI (Feb Brickclean External Brick Cleaner | Cleaning and Deagreasing Solution for Brick, Concrete and Stone Surfaces)

I'm a bit anxious about messing it up / damaging the mortar or something. I contacted a local handyman who suggested a render cleaner which clears off algae and lichen. Spray it on, wait 15mins then rinse it off. Problem is I've already tried this: https://www.amazon.co.uk/Spear-Jackson-Spray-Concentrated-Remover/dp/B011KT373Q?th=1 (Spear & Jackson - Spray and Leave Concentrated Mould, Algae and Lichen Remover) and it doesn't seem to have done anything!! Not really sure what to do

What are you trying to achieve? Shiny-shiny spanking new brickwork? The methods getting it thoroughly clean can be very aggressive and harmful, unless you want to spend weeks picking away at blemishes etc. Regardless, the weather will win out in the end eventually, anyhow.

 

[Ivor Windybottom]

If the darker stuff is living matter, e.g. algae, lichen etc, then it will die and fade away over the years just from the StormDry being applied, as it won't have as much water to drink and will probably get poisoned by the stuff.

The biggest issue I can see from your photos is the messy recent repair. But that should fade and blend in a few years with a bit of weather.

It's just a wall, not antique furniture.

 

[Ivor Windybottom]

The spray and leave stuff may have already killed it, but it just hasn't yet had time to fade away.

 

[John74813]

Ok thanks all. I'll just use spray and leave and then Stormdry it in Spring