How to Clean Algae from Your Roof: A DIY Guide

Have you noticed black streaks and stains that look like molds on your roof? If your roof is made of light-colored asphalt shingles, what you saw is a blue-green algae that grows in warm, humid weather.

The good news? The algae will not cause damage to your roofing. The bad news, though, is that it looks like an eyesore that makes your home’s exterior less picture-perfect. Before your home turns into a haunted house, thanks to your badly looking roof, you need to do something about it.

What to do when your roof has algae on it

You have two options: remove your entire roofing system and install new roof shingles to hide the ugly stains, which is the right solution if your shingles are already worn out and are nearing the end of their service life.
But what if they are not? Then go for the cheaper solution: clean your roof to get rid of the algae.

How to clean your algae-covered roof

Here are the steps on how to properly eliminate algae from your roof shingles:

  • Wet your foundation plantings to protect your plants from the bleach that you will use later.
  • Mix bleach and water.
  • Transfer the mixture to a spray pump with low pressure. Do not use a pressure washer, as it will damage your roof shingles.
  • Spray the cleaning solution to the roof.
  • Insert strips of copper or zinc (about 6 inches wide) under the row of shingling nearest to the peak of the roof. Leave 2 inches of the lower edge exposed. This step will prevent algae from appearing again on your roof.

As you may notice, it does not cost much to get rid of those annoying algae growing on your roof. You do not even have to replace your whole roofing just to maintain the clean look of your roof.