How should I clean an interior brick wall?

September 9, 2009 6:27 AM

How should I clean an interior brick wall?

I have exposed an interior brick wall that had been living behind wood paneling for many years and it looks filthy. I've already cleaned my exterior brick with muriatic acid with great success, but I am hesitant to even attempt to use it inside. Pressure washers aren't happening -- this isn't in my basement.

Googling comes up with suggestions of dish soap and elbow grease, but I doubt this is going to work based on my experience cleaning the outside of the house. Does anyone have firsthand experience in cleaning interior brick? What products/strategies should I use?

posted by bfranklin to home & garden (8 answers total)

I've used muriatic acid indoors before with no problems.
posted by torquemaniac at 6:41 AM on September 9, 2009

Muriatic acid with other areas well covered (like you were painting because of splatter), protective eye-wear, and good ventilation (and/or an inexpensive respirator). I've done this myself a few times.
posted by mrmojoflying at 7:02 AM on September 9, 2009

Depends on what kind of filthy it is. If it's mildewy and stained, then muriatic is probably your best bet. You'll need lots of ventilation, goggles, gloves and a bucket of clean water, of course. If it's dusty and there's flaking mortar, go for a stiff wire brush to remove loose material and see how that goes. Remember, you can dilute muriatic acid. Always add the acid to the water, rather than the other way around.
posted by electroboy at 7:03 AM on September 9, 2009

Personally I'd be very cautious about using hydrochloric (muriatic) acid on indoor brickwork. The reaction with chemicals in and on the brick is likely to release some quite unpleasant vapours. If you do decide to do it, at least get a couple of fans going and open all your windows.

Here's some more extensive advice.
posted by le morte de bea arthur at 7:04 AM on September 9, 2009 [1 favorite]

I knocked a crumbly old wall off interior brick not too long ago and came in here to recommend a wire brush. It is slightly tedious work and you'll want eye protection, but it works.
posted by kmennie at 7:33 AM on September 9, 2009

I recall seeing an HGTV show that recommended a heavy scrub brush and Scrubbing Bubbles bathroom cleaner. Maybe it's worth a shot if dish soap doesn't work and before attempting muriatic.
posted by dayintoday at 8:13 AM on September 9, 2009

Yeah, seconding dayintoday and le_morte_de... advice...

When I pulled plaster off of rowhouse walls in DC doing renovations, generally the most I'd do is brush it off and use some general purpose cleanser... putting muratic inside, would worry about what else you'll get it on, how it'll change the brick - whether you'll neutralize it before sealing the brick - etc...

And, I'd seal the brick if i were u... preferably with a CLEAR (choose, matte, satin, semi-gloss) water base sealant - this'll make sure the mortar won't start crumbling out on ya, and it'll make it easier to clean if you happen to spill a mixed drink on it n-such.

Now, I have had the experience where the chosen method of interior waterproofing prior to applying plaster was a form of tar! Yuk... luckily for me the tar had turned to the consistency of dried paint ... and was able to chip off with chisels, claw hammers, elbow grease before sealing.

But I dunno how much cleaning I'd attempt... guess if it's really bad, maybe try one of the gooey paint on/peel off cleaners that one can peel away paint/stain from block/brick - usually sold in Home Despot. Not cheap, but relatively easy to work with, non-toxic (mostly) and less costic to the surface of old brick.

just my .02
posted by Jiff_and_theChoosyMuthers at 9:12 AM on September 9, 2009 [1 favorite]

Just a follow up for future askers:

- Started with a wire brush (use a copper one, not a steel one!) and clean water. Use this on the brick, not the mortar.
- Dry brushed with a stiff nylon brush.
- Mixed up a half gallon of TSP cleaner (found via le morte's link) and used a 5 gallon of clean water. Used a sponge to apply to and rinse bricks.
- Dry brush again to get sponge-bits off the surface.
- Used a roller with a 3/4" nap to apply Sakrete masonry curer/sealant. Note to anyone else doing this: if the mortar joints turn white, don't panic. It'll dry clear by morning.

End product looks great. Thanks!
posted by bfranklin at 8:08 AM on September 14, 2009 [1 favorite]