With all the moss removal products on the market, you may be wondering if moss is really that big of a deal on the roof. It's not like it has true roots that can burrow into shingles and roof cladding, right? If you live in an area where mossy roofs are a common concern, the following guide can help you determine the best course of action.
How can moss damage a roof?
Moss on its own doesn't lead to roof damage. Damage occurs due to the moisture concerns moss poses. At it's worst, it can begin growing beneath the edge of a shingle. Over time, this lifts up the shingle so that moisture can seep beneath. Eventually, this moisture will cause the sheathing beneath the shingle to rot, and a leak will occur. Replacing both shingles and rotten sheathing is much more time-consuming and expensive than simply having new shingles placed.
Another form of moisture damage occurs due to the trapped moisture in the moss itself. This constant exposure to moisture can cause your shingles to degrade prematurely, meaning you will need to replace your roof more often.
How can you spot damage?
If you can visibly see moss on your roof, damage is a possibility. Of course, one or two pockets of moss isn't as alarming as heavy moss coverage. For minimal issues, keep an eye on the shingles to make sure they are laying flat. If they seem lifted or uneven, moss may be forcing them up and allowing water underneath.
Can you remove moss?
Moss can be removed, but care is necessary. Pressure washing is one option, although this can damage asphalt shingles. If you pursue this route, contract with a professional roofing service to ensure it is done correctly. Moss cleaners are also available. These contain a mild bleach solution or comparable moss killer, which is sprayed onto the roof. Once the moss dies, it can be cleaned off with a sharp spray of water or light scrubbing.
Is it possible to prevent future growth?
Many commercial moss cleaners are designed to temporarily sterilize the roof, which will slow the return of the moss. Of course, if the roof is shaded and in a moist area, moss may eventually return. In this case, zinc strips may be the answer. These strips are installed near the peak of your roof. Each time it rains, a small amount of zinc leaches onto the shingles below. You can't see this zinc layer, but moss can't grow in its presence.
For more help with roof moss, contact a home roofer in your area.