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Cleaning old paint and grime off bricks

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  • Aug 15th, 2017 9:37 am
[OP]
Deal Addict
Nov 24, 2004
4564 posts
1126 upvotes
Toronto

Cleaning old paint and grime off bricks

I'm looking to clean some areas of the brick exterior wall of my circa-1920 Toronto semi. Significant portions of the wall have old paint residue or dried excess mortar on them, or have bricks that have become discoloured with grime or just plain "age".

Looking online, I see recommendations ranging from chemical cleaners with TSP or hydrochloric acid, wire brushes (plus elbow grease) to pressure-washers. I'd appreciate recommendations from anyone who has done this cleaning themselves -- which techniques work best?
3 replies
Deal Addict
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Oct 9, 2010
3128 posts
1310 upvotes
Windsor
Maybe sandblasting?
One who is offended by truth, has no place among those who seek wisdom.
Deal Fanatic
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Oct 12, 2007
8111 posts
6716 upvotes
Ottawa
Frankly, I've never experienced anything on brick where elbow grease is better than a good pw.

We need pics for an idea of scale or what you mean by "significant". What you use depends on how well attached the stuff is. But assuming that you and I see "significant" the same way:

To start, I would pick a cloudy day (to help keep the surface nice and moist) and use a good (ie gas) pressure washer on a medium setting to slowly go at the paint and grime and then wait for it to dry to see what is left to do. If the grime is greasy and persistent, TSP mixed in a pressurized garden sprayer should help there. Let it sit for 15-30 minutes, hose it off, then pressure wash again. For stubborn excess mortar, you may need the highest setting on your pw and go at them slowly.

Make sure that you protect yourself and the garden when doing this.

Also, I would avoid sandlbasting except for extreme situations
[OP]
Deal Addict
Nov 24, 2004
4564 posts
1126 upvotes
Toronto
I'll post some pics tonight. It's a mixture of what I'd call discoloration (some bricks have turned near-black in spots, for some reason), what looks like adhesive residue, paint residue that has to be several decades old at minimum, and mortar "drippings".

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