Here’s the thing: there’s no such thing as an anti-moss shingle. It just doesn’t exist. There are shingles that are anti-algae, but nothing that will keep the moss off without regular maintenance.
Some roof experts will tell you, “Go ahead and put this shingle on and you’ll never have to deal with growth again,” or they’ll tell you it will last 7-10 years. So the homeowner thinks they don’t have to do maintenance. But that’s not true. It may stop the algae, but moss is a different animal.
There are two reasons a roofer would do that. One is that they honestly don’t know; they think it will stop the moss. Either that, or they’re simply lying to the homeowner.
For the first couple of years, nothing’s going to grow on your roof, just because of the manufacturing process. It has oils and things like that that are going to leech off the roof. Let’s get a couple of winters and summers into that roof, and the dirt starts to stick to it. Now you start to grow the moss.
Here’s another thing about the anti-algae shingle: it doesn’t stop them all. They are two specific algae they don’t stop. Guess where they grow most? Right here in the Pacific Northwest. So even though it stops most of the algae, there about 2% of the algae that it won’t touch, and it unfortunately grows out here.
We live in a really green state. We get a lot of rain and sun, and moss just loves it out here. So you’re going to have to maintain your roof. You’re still going to need to call Roof Life of Oregon, have us come out, look at the roof, and prescribe the right way to take care of that moss.