If you find moss, algae, or mold growing on your asphalt shingles, it can be unsightly. But the way they distract from your curb appeal isn’t the only harm they do. They compromise your home’s structural integrity, and they shorten your roof’s lifespan.
The Culprits
Algae looks like dark green stains or black streaks on your roof. It’s often mistaken for dirt. Algae feeds on the limestone filler in your asphalt shingles.
Moss appears as spongy, thick, green patches on your roof. It has a root-like system that attaches to your shingles.
Mold is the slimy, fuzzy, black or brown spots you see. It’s a fungus that thrives with moisture. It can spread into your attic where it poses a health risk.
How Algae, Moss, and Mold Damage Your Roof
All of these lead to shingle deterioration. While the algae is eating away at that limestone filler, moss traps moisture and can lift shingles, leading to deterioration. Your shingles will become brittle and lose their granules.
Moss will grow under the edge of your shingles. As a result, it lifts and curls them. This ruins the watertight seal that shingles normally provide. Rain will be able to find its way under the shingles, leading to leaks.
Both moss and algae retain moisture and hold it against your roof’s surface. Constant dampness will cause the wood in your roof deck to rot.
Algae also reduces your home’s energy efficiency. Those dark streaks and stains absorb more sunlight. This increases the interior temperature of your attic and raises the cost of cooling your home.
Preventing and Removing Algae, Moss, and Mold
Tree trimming is an effective preventative step. By cutting back any overhanging branches, you’ll increase the amount of sunlight reaching your roof. It also reduces the amount of debris that collects on the roof’s surface.
Keep up with gutter maintenance. When they’re clean, the water drains from your roof properly. This prevents moisture from backing up on the shingles.
Once algae, moss, or mold begins to grow on your asphalt shingles, many homeowners remove it with a 50/50 solution of chlorine bleach and water. There are also commercial roof cleaning products available, but the best thing to do is to contact a professional roofer.
Your roofing contractor may install zinc or copper strips near your roof’s peak to prevent future issues. When rainwater runs over these metal strips, they release ions that hinder the growth of algae and moss. When it comes time for a roof replacement, consider shingles that have built-in copper granules for long-term protection.
You can talk to your local roofer about all of your options for combating moss, algae, and mold. Call Home Roofing Solutions in Etna, ME to learn more about caring for asphalt shingles.
