Get matched with top roof cleaners in Bothell, WA

It may require stronger cleansers or chemicals, higher-pressure spray, or scrubbing to completely remove algae from a metal roof. Start with a mild cleanser; if that doesn’t work and you're comfortable doing so, use a stronger mix of ⅓ cup of laundry detergent, 1 quart of bleach, and 3 quarts of water to gently scrub the algae with a soft-bristled brush. If algae is present across large portions of your roof, doesn’t come off with gentle scrubbing and cleansers, or is in hard-to-reach areas, this may be a job better left to a pro.

A professional roof cleaning lasts about a year on average, so it’s best to do it annually. This schedule helps catch any roof problems before they become extensive and helps prevent mold, moss, and algae from forming. If you live near the coast, annual roof cleaning will help prevent salt buildup on your roof. You can add professional roof cleaning to your yearly home maintenance checklist to ensure you never miss a year.

There are several telltale signs that your roof needs to be professionally cleaned. It's best to hire a professional as soon as you notice any indicators of wear to preserve your roof's longevity. Key signs to look for include:

• Moss, Algae, or Plant Growth: Look for moss growth, black streaks (which are often a type of black algae), or any other plant life on your roof's surface.

• Dirt and Grime Buildup: A general layer of dirt and grime can accumulate over time.

• Leaf Buildup: An accumulation of leaves, especially in the gutters, is a clear sign.

• Buildup Under Shingles: Dirt and debris can get trapped under the edges of your shingles.

• Shifting Roof Shingles: While this can indicate other problems, it can also be a sign that cleaning and maintenance are overdue.

• Comparison to Neighbors: If your roof appears significantly dirtier or different from your neighbors' roofs, that’s another sign it may be time for a cleaning.

Roof cleaning can damage shingles if it’s done incorrectly—like with a high-power power washer—but it likely won’t damage your roof if you pay to have an expert do the work. A professional roof cleaner will use a gentle cleaning solution and a cleaning method that matches your roof material to ensure the process doesn’t damage the roof. Some homeowners worry that roof cleaning will shorten the life of their roof by removing shingle particles or protective coatings, but it often extends roof life by removing plants that cause damage and improves your home’s curb appeal simultaneously.