How To Prevent Black Streaks On Your Roof

Posted on: 6 October 2015

Black streaks can develop on your roof over time due to weather exposure. However, they are not simply discoloration caused by wear and tear: black streaks are actually indicative of small amounts of mold and mildew growth on your roof. If left unchecked, this problem can develop into a serious health hazard, as mold can cause or aggravate respiratory conditions. Thankfully, removing and preventing mold streaks on your roof is a fairly simple process.

Removing Black Streaks

Existing black streaks on your roof can be easily removed with a homemade solution. All you need is bleach, warm water, a spray bottle, and a garden hose with a spray nozzle. All of these items can be found at most hardware stores. You may also want to wear gloves and safety goggles to protect yourself from the bleach.

Mix the bleach and water together into a solution of one part bleach to four parts water in the spray bottle.

Climb up onto the roof and spray the solution liberally onto the areas that are heavily streaked.

Let the solution sit for an hour. This will kill all of the mold and mildew on your roof, but will not start to degrade your shingles.

Rinse the solution off of your roof using the garden hose. Your shingles should have returned to their normal color. If not, repeat as needed.

Preventing Black Streaks

In order to prevent black streaks from developing on your roof, you need to prevent mold and mildew from growing on the shingles. While you can climb up onto your roof and apply a bleach solution every few months, this is an impractical and cumbersome solution.

Instead, you can install zinc strips, which will passively inhibit the growth of mold and mildew. When rain hits these strips, it wears a tiny bit of the metal away and carries it down the roof. Zinc is toxic to mold and mildew and will stop it from growing.

In order to install zinc strips, you'll need the strips themselves, a hammer, a pair of pliers, and roofing nails. Again, these items are available at most hardware stores.

Unroll the zinc strips along the peak of your roof and nail the strip in every foot or so to ensure that it is secure.

If there is a roof installation, like a chimney or skylight, which will block rain flowing down the roof, you'll want to cut a section of the strip off with the pliers and nail it in underneath the installation, as otherwise the zinc runoff will be blocked and mold and mildew will be able to grow beneath the installation in question.

For more tips, or to have professional help installing zinc strips, contact a company like HomeTowne Roofing.