Should I powerwash asbestos siding?

May 19, 2007 10:16 AM

Is it safe to powerwash asbestos/cement siding?

I have an old house with asbestos/cement siding. I'd like to remove it and put on new siding, but that job is prohibitively expensive right now. So, I think I'll just put on a fresh coat of paint. Should I prep the surface by powerwashing, or will that release harmful asbestos particles?

posted by eirelander to home & garden (9 comments total)

I had someone paint my house of asbestos/cement shingles a few years back, and they did not powerwash. However, I think they did use a special kind of paint. The shingles are very absorbent, so the issue of the paint bonding to the surface, which is why you powerwash, is not really an issue.

Powerwashing will also release a tremendous amount of particles of your shingles into the air. I powerwashed painted siding once and when I was done my neighbors car sat in their driveway with millions of little specks of my paint dried onto it. I think with asbestos/cement, it will only be worse.
posted by stupidsexyFlanders at 10:53 AM on May 19, 2007

Do you have mildew or other oddness on the boards? That is, is cleaning that off the goal? Would you be able to use a normal hose and soapy sponge?
posted by Alt F4 at 11:01 AM on May 19, 2007

This is something I would avoid. The power washer is going to release particles of asbestos regardless of how careful you are with it. Although most of those particles will be trapped in the water while you are washing it, the water will eventually evaporate and release those particles. Clean-up for something like this could cost even more money.

Just paint the siding and seal the asbestos in.
posted by 517 at 11:22 AM on May 19, 2007

All good points.

My biggest concern was premature peeling if I painted over a dirty surface. There is no mildew, but there is a little chalky surface resin that comes off when wiped with a finger.

Maybe I'll try the low impact approach and clean it with soap and water first.
posted by eirelander at 12:12 PM on May 19, 2007

It's seriously not worth the risk. My dad died at the end of February from Mesothelioma (asbestos-induced cancer) and his physician sourced it to a one-time removal of an asbestos furnace that took all of two hours when he was 19. Really, do you want to die an extended, painful death just because you powerwashed your siding and breathed in asbestos fibres? I don't mean to be overreacting here, but my dad went through five years of experimental chemotherapy before spending four months in bed so exhausted and sick he couldn't even get up to use the bathroom. So not worth it.
posted by MeetMegan at 12:57 PM on May 19, 2007

Allow me to remake 517's point more emphatically.

Power washers produce a very fine aerosol; if you use one on asbestos shingles, the droplets of water in this aerosol will contain very fine fibers of asbestos, which will be conveyed into the deepest recesses of your lungs. If I were trying to come up with a way to expose you (and anyone around you) to asbestos, I could only wish to be clever enough to come up with such an effective method.
posted by jamjam at 1:57 PM on May 19, 2007

So, I called the local Sherwin Williams and they recommended washing the walls with a 1:3 solution of bleach:water. I washed a small area by hand, rinsed with a hose, and it seems to work great. Simple bleach, water, and elbow grease removed most of the chalkiness - which I'm happy about because I'm convinced powerwashing would have been a bad idea.
posted by eirelander at 7:33 PM on May 19, 2007

I'm just gonna chime in here and say "asbestos cement" sheet is not made of asbestos. At least, not for a long time. All you people panicking about asbestos contamination are paranoid.

Bleach water sounds like a simple idea and no more labour-intensive than the powerwasher... but be real careful where it runs to. That could be a lot of bleach and it will kill your garden. Letting it run into the drain isn't much nicer.
posted by polyglot at 8:47 PM on May 19, 2007

I'm just gonna chime in here and say "asbestos cement" sheet is not made of asbestos. At least, not for a long time.

However lots of houses are still around that were built during the decades when asbestos was indeed used.

So it's not very paranoid at all, especially if you know your house was built during that time period.
posted by flug at 7:22 AM on June 7, 2007