Mailbag: How Do I Remove Mildew From My Asphalt Roof?

I am going to be starting a new segment on this little blog of ours. There’s been a couple people using the Contact Us page to ask different questions about painting, staining, colors, and many other things about the coatings industry. I’ve decided to make a mailbag post of some of these questions. If you have one, just fill out the form on the Mailbag Form page.

First question comes from Eric in Alpharetta, GA:

My asphalt roof is starting to mildew and show age. Is there any products you can recommend to clean up and extend the life of my asphalt roof?

There’s actually a couple different things you can use to freshen up your asphalt roof, Eric.

First, to clean your roof, use the Defy Roof Cleaner Concentrate. The most common culprit causing the black streaks on roofs is a blue-green algae called Gloeocapsa magma and is a common sight on asphalt roofs. Defy Roof Cleaner is a concentrate and a gallon container can make you roughly six to seven gallons and will cover 700-900 square feet. Defy Roof Cleaner Concentrate can be applied with the Roof Cleaner Applicator. Using roofing cleaning products like chlorine bleach or sodium hydroxide will accelerate corrosion of metal gutters, downspouts, flashings, and roofing fasteners. Sodium hydroxide is the active ingredient found in many paint strippers, oven cleaners and drain cleaners. It is caustic and high concentrations may cause irreversible damage to asphalt shingle roofs. Besides the obvious health risks of handling sodium hydroxide and chlorine bleaches, strong bleach solutions will damage almost any hard surface that comes in contact with it. Asphalt shingles are no exception.

After a good cleaning, you can either leave it be or use a sealer like Infiniti Shingle Sealer to further increase the longevity of your asphalt roof. Infiniti Shingle Sealer is great for extending the life of your asphalt roof and will also seal the granules down and gives a satin finish. Infiniti Shingle Sealer is a 100% Acrylic (water based) sealer and you will get about 400 square feet out of a gallon can.

Of course, you don’t have to put Infiniti Shingle Sealer on your asphalt roof but it is just an extra step to increase the life. Also, if you have a newer asphalt roof and don’t want it to age/mildew so quickly, you can go ahead and put the Infiniti Shingle Sealer on there to have it last even longer.

I hope that was a good answer to your question, Eric. If anyone else has questions, please be sure to fill out the Mailbag Form and I will get to answering it as soon as possible.

Defy Roof Cleaning Concentrate Before After