Roof Cleaning

What are the black streaks on my roof?

It’s an algae called Gloeocapsa magma. It spreads through the air and feeds on the limestone in most asphalt shingles. Mostly it just looks bad, but it holds moisture, which can wear out shingles faster over time.

What kinds of roofs do you clean?

We mostly clean asphalt shingle and slate roofs. We don’t clean cedar shake roofs. We look at every roof in person at the estimate to make sure it’s a good fit.

Do you pressure wash roofs?

Never. High pressure can knock the protective granules off your shingles and damage the roof. The roofing manufacturers warn against it too. We use a gentle, bleach-based cleaning solution with no pressure, the method the roofing manufacturers recommend.

How soon will my roof look clean?

It should be most of the way there when we leave. The rest fades over the next few weeks as the rain rinses it away. On some roofs we rinse when we’re done, and on others we let the rain finish the job. It depends on the roof.

What if some streaks are still there after a while?

Roof cleaning can be a slow process, so not every spot is gone the day we leave. If you still see spots after a few rains, let us know and we’ll come back and touch them up at no extra charge.

What about my plants?

We water the plants around the house before we start, keep rinsing them with clean water while we work, and rinse them well again when we’re done. If you have delicate plants, a pool or a pond, let us know.

How long will it last?

Usually three to five years, depending on how much shade, trees and humidity your roof gets. The algae does come back eventually, so many customers have it done again every few years.

Is roof cleaning worth it?

It costs a small fraction of a new roof. It makes the whole house look better, and getting the algae and moss off may help your shingles last longer.

Do I need to be home?

No. As long as we can get around the house and use your outside water spigot, we can do the work while you’re out.

How do I get ready?

Turn on the outside water, move cars away from the house, and move patio furniture and potted plants that sit right next to the house (or ask us to help). Please keep pets inside while we work.

What if it rains?

We do work in the rain, but we always err on the side of safety. If weather is an issue, we’ll contact you the morning of your appointment to make other arrangements.

How do I get an estimate?

You can request a free estimate here or email us at windowsonlyllc@gmail.com. We’ll set up a time to come out and take a look.