Roofs in shaded areas, such as on the north side of the home or under heavy tree cover, can suffer from moss and algae growth. Fortunately, not all roofing materials are subject to this growth or damaged by it. Find out where your preferred roofing type stands before your next replacement.

#1: Metal Roofing

In a shaded or moss prone area, nothing beats a metal roof. If algae or moss does attempt to grow, you can simply rinse it off with a sharp spray of water. Often, the roof is shaded because of trees. Fortunately, tree debris simply rinse off and falling branches rarely damage metal.

Metal roofs come in a variety of designs, from standing seam style to corrugated. You can even find metal roof tiles that emulate the look and colors of a clay tile roof. Metal requires little maintenance and it can last a lifetime.

#2: Clay and Tile

Although clay and tile roofs aren't moss and algae resistant, the problem is only aesthetic and it doesn't compromise the quality of these roofing materials. Algae can leave dark stains on tile, but moss tends to only grow in the valleys of the roof.

Although not dangerous to the roof, this growth can be unattractive. Periodic pressure washing is the main method used to combat the stains. Zinc strips are sometimes installed to help prevent the algae growth, or the tiles can be chemically treated to inhibit growth.

In areas with heavy tree cover, tiles can also be prone to breakage from falling branches.

#3: Moss-Resistant Asphalt

Algae and moss resistant shingles have the appearance of standard asphalt, but they are a better option in a shaded area. These shingles feature small amounts of copper in the asphalt overlay. The copper prevents moss and algae from forming.

Resistant shingles don't remain so forever. After a few years, the copper will begin to break free of the shingles and moss and algae can become a problem again. They also have a shorter lifespan than tile or metal roofs, so you will need to plan for replacement every 10 to 30 years.

#4: Standard Asphalt and Wood

Standard asphalt and wood shingles are the worst choice in a shaded location, because moss and algae thrive on these materials. Moss can work its way beneath the shingles, lifting them up and causing a leak.

If you do decide to have asphalt or wood shingles, have zinc strips installed along the ridge line. These strips leech zinc over the entire roof when it rains, which helps inhibit growth. Schedule regular cleanings to remove any moss or algae before it cause a more severe roof problem.

Contact professional roofing suppliers, such as Danforth Roofing Supply Ltd, to choose your preferred material.