Mould on your siding?
Power washers might be safe, but always check first
A how-to guru advises readers on how to best remove mould and mildew from a home’s siding.
Q I’ve lived in my house for 25 years. In the past couple of years, some kind of mould or mildew has formed on the vinyl siding on the north side. Why is this happening and how do I address it? If it is physically challenging or involves chemicals, can I hire someone to remove it? A Whatever the type of siding, algae and mould are most likely to form on the north side of a house because it stays shaded and damp.
Several factors might explain why that didn’t happen before. Perhaps trees weren’t as tall? Or it could be that the vinyl was slicker when it was new and that bits of grime that became attached over the years now give rain a better grip, encouraging algae and mildew to form.
The growth should come off fairly easily if you wash the wall with a little soap and water, using a soft cloth or a long-handled, soft-bristle brush, like one you’d use to wash a car.
Hardware stores and home centres carry specialty cleaners that are gentle and work well.
The Vinyl Siding Institute, a trade group (vinylsiding.org), recommends starting at the bottom of the wall and working up, taking care to rinse thoroughly as you finish each area.
Although it might seem to make more sense to start at the top, working up from the bottom minimizes the chance of having dirt-laden, soapy water dry on the siding and stick.
You can probably use a power washer, although the Vinyl Siding Institute recommends checking with the manufacturer first. But when siding is 25 years old or older, as in your case, the likelihood that the company is still in business, even if you know the name, is slim.
If you want to hire someone, the crew will almost certainly want to use a power washer.
As a rough guide for what it might cost, Kevco Building Services, a company that cleans siding throughout the Washington area, charges a minimum of $189 to clean one or two sides of a house, a minimum of $229 to clean three sides, and a minimum of $269 for four sides.
The price could rise if the house is large or especially tall.