(Editor's Note:  We specialize in green remodeling, which is a good thing; this post is about a damaging kind of green.) You turn into the driveway and glance up, noticing your roof is green.  And not the eco-friendly green.  You think, 'Oh no – something’s growing on top of my house!'

You may have moss or algae growing on the roof of your home.  It’s not an uncommon problem, especially in areas that have very wet winters or prolonged rainy seasons.  Roofs that are in the shade are particularly prone to developing green growth.

No doubt, it can be unsightly to have living organisms sprouting out of the cracks in your roof, but that isn’t the worst part.  If it goes untended it can cause major roofing problems. 04apr19b2a16Typically, lichen and mosses like to grow on the north-facing slopes of a roof.  Because of our location in the northern hemisphere, these areas of the roof don’t get enough sunlight to fully dry out.  Moisture is the primary factor in the spread of algae and other green growths on a roof.

Preventative Maintenance

Mosses can grow on most roof types, as long as they have the moisture needed to survive. They thrive in areas where the roof is shaded by trees or covered in debris. Because of this, we advise homeowners to have their roofs maintained regularly by a MN roofing contractor. They will clean off all algae and lichens along with making any necessary repairs.  At Quarve Contractors we recommend that you have this done in November or December: after the leaves have fallen but before the snow starts flying here in the Minneapolis area.

Protecting Your Roof from Discoloration

There are a number of quality products on the market today that reduce the roof growths.  GAF StainGuard labeled shingles are excellent for new building projects, as they have a 10 year warranty against discoloration.  Just be sure the shingles you purchase have the StainGuard logo.   

If your home is not ready for a roof replacement, you could consider having zinc strips installed in infested areas to minimize the growth of mosses.  How do zinc strips work? When rain water hits the roof it reacts with the zinc strips, producing a solution in which organic materials are unable grow. Thus the “green roof problem” is solved.

If you have had problems with moss growth on your roof, contact Quarve Contracting today. As a MN licensed exterior remodeling company, we specialize in roof repair and replacement, including the installation of GAF asphalt shingles. We are your best solution for all roofing maintenance and renovation.