Roof Cleaning & Treating

What Are Those Black Streaks?

roof cleaning in Delaware & Philadelphia

For many years, roof discoloration caused by algae has been observed throughout the United States and Canada. The discoloration usually has a brown to black appearance, and may be mistaken for soot, dirt, moss, or tree droppings.

The primary species of algae being observed is called Gloeocapsa Magma. This type of algae is contained in and transported through the air, and tends to collect and grow upon roofing structures. Natural pigments produced by this algae may cause a white or light colored roof to gradually turn brown or black. The algae discolorations should not be confused with moss or tree droppings, which typically produce only localized discolorations.

Besides looking bad, this algae also feeds on the limestone filler in your shingles. It is literally eating away at your roof!

remove roof algae

Algae on roof

remove roof algae

No more Algae!

Got Algae?

Call Vesta Wash! We have a proprietary method of killing the algae, washing, and treating your roof using the standards and procedures set forth by the Asphalt Roofing Manufacturers Association (ARMA). This is a safe, NON-PRESSURE, chemical wash that will NOT harm your roof or your landscaping. And, because it is approved by ARMA, it will NOT void your roof’s warranty!

We learned our methods and chemical solutions from one of the oldest, most well-established roof cleaning companies in Tampa, Florida, where their humid climate has made roof cleaning a necessity for decades.

Should I Replace My Roof Or Have It Cleaned?

If your roof shingles are still under their warranty period (typically 25 to 40 years) and still in good shape, call us to have it cleaned. If there are any leaks due to minor shingle damage or a few missing shingles, call us anyway and we can make simple repairs first! Pay a fraction of the cost of a new roof!


We can clean those unsightly BLACK streaks off of your Roof. This will make your roof last longer and look new longer!

Q. Do I have to replace my roof to make it look new again?
A. If black streaks are your problem, you usually don’t have to replace your roof. Shingle manufacturers recommend that you clean your roof every couple of years; this will prolong the life of your roof and keep it looking new.

Q. What are the black streaks?
A. Black streaks are caused by a hardy type of algae called Gloeoclapsa Magma. This algae feeds on the limestone in your shingles. The streaks form as the rain slowly spreads the algae down your roof.

Q. Is cleaning my roof merely a cosmetic repair?
A. NO. The black streaks will prevent your shingles from deflecting the sun properly and can increase your cooling costs. Also, since the algae is feeding on the limestone in your shingles, it is slowly breaking them down. By not cleaning your roof, you are reducing the life of your shingles by up to 50%!

Q. You’re a pressure washing company, will you damage my roof with high pressure?
A. NO. We do not use a pressure washer at all when cleaning roofs. We use a specialized LOW PRESSURE system designed to gently clean the algae from the surface of your roof. Our system uses no more pressure than your garden hose! We simply apply the cleaner, allow it to dwell and rinse it clean.