Cleaning Asbestos Cement board siding

fpgoaJune 18, 2013

We have a late 1950's split level in suburban NJ with what I believe has been referred to as asbestos board cement siding. One of my elderly neighbors (original owner) recently had a fly by night painting service come to his identical house and did some sort of powerwash/ sanding process and then paint it and it looks terrible. It has shiny spots, rub spots (visible from the street) and it basically looks like a fly by night job.

We are not well off enough to get new siding nor painting but want to get the green "shotgun spore" build up off of the north side of the house and clean various other dirt which makes it less than spotless white around. My wife wants the guy who cleans out our gutters to powerwash the house while I am concerned that powerwashing might chip or be too abrasive on the ancient siding.
What is the best way to clean this style of siding?

Thank you for reporting this comment. Undo

I'd obviously avoid any abrasive processes, but a gentle scrubbing with a RV brush would probably get it fairly clean. Use a house-wash attachment to your hose to apply the cleanser, scrub, rinse. Look for a cleanser that announces its particular effect on mildew. If the siding is still stained after physically scrubbing, maybe look into an application of bleach.
Oh, yeah, protect the plants from the cleanser and definitely from any bleach.

    Bookmark   June 18, 2013 at 7:28PM
Thank you for reporting this comment. Undo

I'd try what Casey has suggested in an inconspicuous spot. If it works do the whole surface.

But start at the bottom, not the top. Sounds counter-intuitive because you'll be washing the upper ick down over the lower, already- cleaned walls. But the lower walls be wet and the stuff from above will slide right off. If you start at the top, you may get the stuff running down and making stains. Finish up each vertical section with a thorough rinse from the top down.

Work vertically in sections about 4 to 6 feet wide. That is pretty much as far as you can reach from side to side once you're up on a ladder.

There are all kinds of scrub brushes: flat, rectangular floor ones, ones with splayed-out bristles (good for cleaning the under-edge of a siding lap); narrow ones which work particularly well in the right angle between boards, etc. Even tooth and nail brushes may come in handy. Be prepared to try an assortment. I have washed a few houses by hand, and I find the OXO brushes pretty comfortable in the hand, but start with what you already have.

When rinsing or using the hose be particularly mindful of not spraying up at too narrow an angle which might drive water under the laps. Try to get the water on more at a right angle, where it will just cascade down.

If you're going to work on a ladder you might try getting one of those U-shaped metal stand-offs. They make it easy to scrub against a house. You can take the cleaning solution up in a bucket and just hang it over the ladder rung with a paint bucket hook.

You're going to get wet doing this, wear old clothes, and do it on a warm day.



    Bookmark   June 18, 2013 at 11:08PM
Thank you for reporting this comment. Undo

An 'acid brush' on a painter's pole should do fine.

    Bookmark   June 19, 2013 at 9:42AM
Sign Up to comment
More Discussions
Are colored appliances going to come back?
I hope so. I have a stainless steel stove (front only)...
Ceiling after dormer
Riddle me this. I am living in a 1910 1 3/4 story bungalow with...
Old-Growth Heart pine paneling -- reused as flooring?
Hi, My new 1939 colonial has a family room and foyer...
stone house
Do any of you out there own a real stone house? Not...
Anyone know what this is?????
Does anyone on the forum know what this is? Found it...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™