Algae & Moss Prevention and Cleaning for Asphalt Roofing Systems

Posted on: July 7, 2016

Keeping your Baltimore-area roof in good condition is important to making sure that it lasts a long time. This includes cleaning off algae and moss, and taking steps to prevent it from growing on your roof. Although somewhat similar in nature – especially in the way they grow in moist conditions – algae and moss are different from one another.

What is Algae?

Algae can be identified by black discoloration and streaks on the surface of the roof. In fact, it’s often mistaken for mold or mildew. The dark pigmented sheath that causes the discoloration is used by algae as a way to protect itself from the ultraviolet rays of the sun. Once it becomes visible on your roof, it’s most likely already been present for months.

Algae won’t damage your roof, but it will affect the aesthetic value of your home and will have a negative impact on the effectiveness of cool roofs.

What is Moss?

Moss is a non-vascular plant that absorbs water through its leaves instead of its root system (like other plants). Moss spores can be spread by the wind as well as by animals. Unlike algae, moss can be damaging to your roof.

Specifically, it can cause the leading edges of your shingles to curl or lift, which increases the chance of strong winds blowing shingles off the roof. Severe moss problems can also lead to moisture damage.

Cleaning Moss and Algae

A solution of water and liquid chlorine bleach can be used to clean moss and algae from the roof. It will need to be applied using a sprayer and then rinsed afterwards using low pressure water.

Because of the inherent danger of climbing a roof to clean it – as well as the need to be extremely careful with the use of chlorine bleach – it’s recommended that you have a professional clean the moss and algae from your roof instead.

How to Prevent the Growth of Algae and Moss

There are a number of things that you can do to prevent algae and moss from growing on your roof. These include:

  • Trim any tree branches that hang over your roof -This allows the roof to be exposed by more sunlight, there by reducing the roof’s exposure to moisture. It will also help minimize the amount of debris that will accumulate on your roof that moss especially will feed on.
  • Keep air flow directed downward – Air should flow down the roof’s slope to prevent debris from being blown under the edges of your shingles.
  • Keep your gutters clean - Clean gutters will drain properly. If they become clogged, rainwater and moisture will build up near the roof.
  • Clean debris off the roof - Keep your roof clear of any debris that have collected using a leaf blower or another non-abrasive method.

Be sure to take steps to prevent algae and moss from growing on your roof. If you need algae or moss to be removed from your roof, schedule an appointment with us at Park Heights Roofing today.