How Often Should You Wash Your Siding on the North Shore?

If your siding has a green tint creeping up the north side, you're not doing anything wrong. Homes between Duluth and Grand Marais sit in some of the best algae-growing conditions in Minnesota: damp air off the lake, long stretches of shade from mature trees, and a freeze-thaw cycle that keeps moisture in every crevice.

The short answer

For most North Shore homes, a soft wash every two to three years keeps siding looking like it should. Homes with heavy tree cover, north-facing walls near the lake, or cabins that sit closed up most of the year often need a wash closer to every other year.

Why it comes back

The green film is algae, and it feeds on moisture and shade. You can't change your lot's shade or the lake's damp, so the realistic goal is staying ahead of it rather than beating it once. Waiting until the whole wall is green doesn't just look rough; the growth holds moisture against the siding, and that shortens the life of the finish.

Soft wash, not pressure wash

Siding should never meet high pressure. Blasting vinyl or wood can force water behind the panels and strip the finish, which is why siding manufacturers recommend low-pressure washing with a cleaning solution that does the work. That's how our crew does every house.

What you can do between washes

Keep sprinklers from hitting the siding, trim branches that keep walls in permanent shade, and rinse off grill smoke or pollen with a garden hose when you see it. None of that replaces a real wash, but it stretches the time between them.