Your Place: Power wash siding before painting

Posted: April 20, 2013

Question: Our house was fitted with white aluminum siding by the prior owners decades ago. We've been in it about 16 years now.

The siding has held up OK except in the front above the porch, which gets the morning sun. It is losing its paint. Is there a preferred method of dealing with this?

Answer: Yes there is. And for advice about anything paint, I turn to the experts at the Paint Quality Institute in Spring House.

First, how should you prepare old aluminum siding before painting? And what type of primer is the best for siding?

Remove as much chalk, dirt, and mildew as you can. Chalk is powdery pigment on the surface of weathered siding that comes off when you rub the palm of your hand over it.

Removal is done by power washing or by scrubbing and rinsing.

The only times a primer would be needed are if any bare aluminum is exposed or if there is still much chalk left on the surface.

In the first situation, remove any white oxide with a nonmetallic scouring pad such as ScotchBrite, then wash off and rinse to make way for a latex corrosion-inhibitive primer. In the second scenario, apply a quality exterior alkyd - "oil-based" - primer recommended for aluminum siding by the manufacturer.

One consumer asked the institute experts whether he should wipe the siding with mineral spirits before priming, having had to use a sander to remove road salt from the surface that was now badly pitted.

The answer is no - unless you have some oily contaminant such as road tar on the siding. The road salt removed was probably white aluminum corrosion (aluminum oxide).

If you do prime everything, you will get a more uniform appearance from the paint, compared with if you only prime some parts.

Here's a great resource: Bookmark the institute at

A familiar topic. Chicago reader Sam Portero wrote to weigh in on discussions concerning how to get rid of lingering cat-urine odors in the basement.

He said the house he and his partner owned before they bought their current condo had the same cat-urine issue.

Locating the affected area was difficult, but they found it was concentrated in one area, Portero said.

"After trying all kinds of solutions, we finally went to a pet store and bought a product for removing urine odor that was an enzyme-eating solution," he said.

"Two gallons at full strength, applied slowly, and in liberal doses to allow it to seep into the affected area without running off eventually did the trick in a couple of weeks."

"It does takes time for it to work," Portero said, "but that enzyme did seem to be the key. Most everything else was just a cover-up."

Q: Do you know of a good grout and stone sealer?

The stone is on a kitchen backsplash. The floor tiles have grout that is supposed to be resistant to stains and grime, but to be on the safe side, I would like to protect it.

A: A good resource to check out is, the website of Stone Care International, a company that I came across several years back at the Kitchen and Bath Show in Chicago.

Not only do they manufacture stone care products, but their site offers a bucketful of care and maintenance tips that I have used on my floor tile and slate backsplash to keep them looking new.

Regular maintenance is the best defense in the homeowner's bag of tricks. Once you get into the routine of tackling small problems as they arise, they don't often get much bigger.

Questions? E-mail Alan J. Heavens at or write him at The Inquirer, Box 8263, Philadelphia 19101. Volume prohibits individual replies.

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