Roof Cleaning

Those nasty black streaks on your roof are not just an eye sore, they could be damaging your shingles. Windows Only provides safe, effective roof cleaning without the hassle. Let us take care of your roof today. Contact us today to schedule a FREE no obligation estimate or repeat visit.

Roof Wash FAQs

What kinds of roofs do you clean? 
We clean asphalt shingles.  Slate roofs require a site visit to determine if we can clean it or not.  We do not clean cedar shakes.

What are the black streaks on my roof? The black streaks are actually an algae called Gloeocapsa Magma.  The algae feeds on the minerals present in most roofing shingles, which may cause slow deterioration of the shingles.

How does roof washing work? First, we do not use pressure of any kind.  Pressure washing a roof can disturb the shingle grit and cause all sorts of problems.  The treatment we use is as gentle as rain. We spray a solution to kill algae, mildew, and lichen.  Once they die, they will release from the shingles and rinse off during subsequent rains.

What about my plants?  Do they need to be protected during roof washing? No need to worry about your plants.  We take care of protecting your landscaping.  A “ground man” thoroughly waters the plants and ground beneath the eaves before, during, and after roof washing to ensure that all plants are sufficiently protected.

Do you need to climb on my roof? In most cases we do not need to climb on the roof.  If we find we do need to climb a roof, our technicians are trained in safe and responsible methods for using ladders and climbing on roofs.

Why does roof cleaning seem so expensive? Roof cleaning does seem expensive, but if you think about it, how much does it cost to replace an entire roof?  Removing the algae and lichen, which may be deteriorating your shingles, may extend the life of your roof.  In addition, it may take more than one treatment to ensure that all the algae and lichen release.  We do not charge for subsequent visits.

How long will the treatment last? Depending on the amount of humidity and shade, the results should last from three to five years.

Do I need to be home while you are cleaning my roof? No, you do not need to be home.  We do not need access to the interior of your home to clean the roof.

How do I get an estimate for roof washing?  You can get an instant quote right here or contact us at or 301-654-0853.  We’d be happy to answer any questions and set up an estimate for you.