Why Roofs Are NOT Naturally Green And How To Address It

Posted on: 16 June 2017

Buying a home with a green roof may be country-quaint to you, but the truth is, roofs are not typically green, nor can you buy green asphalt shingles. In fact, if the majority of your roof is quite green, you may have a very serious problem on your hands. Be sure to call a roofer out to confirm what the problem is, and find out how to address it.

Algae and Moss

Yep, algae can grow on your roof. All it needs is a little rotting debris and lots of moisture. Shingles tend to collect a lot of moisture during the really wet seasons of the year. As for the rotting debris, tree leaves create enough of the necessary debris to give the algae room to grow. Moss is also possible under similar circumstances. When you already have a lot of moss and/or algae growing on the ground around your foundation, it is easy to see how the spores might travel up to the roof and take root there.

Why a Green Roof Is a Problem

Moss and algae show that there is a lot of rot and excessive moisture present. Because the rot remains in place, and because the shingles collect moisture, the moss and/or algae have taken root. While the roots of these plants are not very deep, they tend to hold onto moisture and rotting debris, which can contribute to water damage and a rotting roof (unless, of course, your roof is already rotten/rotting, then the moss/algae is present because the roof is feeding it).

What the Roofer Will Do

First and foremost, the roofer has to determine if your roof is rotting. Spraying a fungicide or herbicide on the roof to kill the moss or algae will have little long-term effect if your roof is rotten enough to just regrow the moss/algae. Repairing the roof, removing the water damaged areas, and then spraying to kill these plant-like invaders is what needs to be done to keep your roof healthy. The roofer may return to scrape any rotting debris from the roof and then use a powerwasher to clear the roof of these problems. If the problem is severe enough, the shingles may also need to be replaced.

Checking the Roof Annually

When you have already experienced the impact of moss and/or algae, you know that you need to check the roof again once a year. Usually late spring or early fall are good times to do this, since that is when moss and algae make their presences known. Then the roofer you hired before can come back to deal with this problem.