We’re replacing a asphalt shingle roof that has lot’s of mold and moss growing on the surface (densely wooded lot). The owner is concerned about mold growing on the new roof. Most shingles have anti-mold agents inherent in the material. Is that enough? I’ve heard about using zinc strips at the ridge, rainwater drips over the strip and the zinc water helps prevent mold. Is this true? (never heard of it before). Any other suggestions?
Thanks,
RobW
Replies
The strips shouldn't be necessary with algea (algae?) resistant shingles. These shingles have flecks of copper mixed in with the aggregate and basically do a time release.
REMEMBER THE BOSTON BATWANGER.
I'd be surprised if "most" shingle have the agents in them. Check the specs carefully to be sure.
Zinc oxide does prevent mold and algae. That's what some of the shingles have. You could also install a strip of zinc under the ridge shingles (exposed to the weather, of course). As the zinc oxidizes it runs down the roof and provides protection. But, it is only effective partially down the roof. It would not hurt to use it even if the shingles contained it too, because it is so cheap to install.
Any branches that could be trimmed to get better air circulation, and, better yet, sunlight onto the roof would help, too.
I'd be surprised if "most" shingle have the agents in them
It depends on where you are. The further south you are the more likely they are to have it. Pretty much everything that's sold in KY is advertised as "algae resistant". REMEMBER THE BOSTON BATWANGER.
The zinc (or copper) strips are cheap (compared to the cost of the roof), inobstrusive, and can't hurt anything. I'd be inclined to use them, since you know this is a "problem" location.
Also note that copper/zinc is only moderately effective against moss, though much more effective against algae. So the more "bang" you have there the better.
Any other suggestions?
cut back the trees.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
IMHO zinc strips aren't worth the effort or money after the first 3 weeks. I'm happy to do it for HOs, but I find that the preventative measures as posted are good. And if things get bad up there sprinkle "Sunlight" washing powder liberally over the roof. Sure, it makes lovely bubbles in the eavestrough, but it also kills the moss, etc, too.
cheers
***I'm a contractor - but I'm trying to go straight!***