If you have a roof that has been invaded by moss and now needs replacement, then you may be wondering what you can do to prevent this problem in the future. Moss itself isn't damaging to a roof. Problems occur either from the moisture the moss traps against the shingles, or if the moss gets under a shingle and lifts it, thus allowing water beneath. The following are a few things to keep the new roof free of these issues:
Change up your roofing materials
Some roofing options aren't as likely to suffer any damage from moss, or even to allow its growth. Asphalt shingles, which also happen to be the most common, are the ones most commonly affected by moss problems. By switching to a metal roof or clay shingles, you are less likely to see moss growth. Algae (not moss) may grow on clay, but this only causes discoloration and does not affect the integrity of the shingles. The surface of a metal roof does not allow for moss growth since it needs a porous surface, so this may be the best choice if you previously had a major moss issue.
Install zinc rods
For those that prefer standard asphalt shingles, there is still hope. Zinc kills existing moss and prevents new moss from growing. You don't need a lot, but you need it applied consistently to the shingles to reap the benefit. The easiest way to do this is to have zinc rods installed beneath the roof cap or near the peak of your roof. Each time it rains, a small amount of zinc will dissolve and wash down your roof, preventing the growth of moss.
Schedule a tree trim
Moss needs shade to grow, which is often provided by landscape trees. If you will be getting a new roof, also schedule to have the trees trimmed back before the roofers arrive. If you can't trim the trees back completely or if you would like to keep some of the shade, then have the canopies of the trees thinned to allow some dappled sunlight through. This may be sufficient if you combine it with moss-resistant roofing or zinc strips. As an added benefit, trimming back the trees will cut down on the amount of leaves and debris that is dropped onto your new roof.
For more help planning for moss resistance, or simply to see all the roofing options that are available to you, contact a roofing contractor like WNC Roofing in your area.