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Remove Moss on Roof...or Replace Your Roof. Which Will It Be?
Moss on Roof

Moss on Roof

© Lee Wallender; licensed to About.com
See the picture above? This is a picture of an unnamed neighbor's house, with moss growing like a lawn. Think that's bad? I've got another neighbor whose roof-moss is so thick, you cannot see shingles anymore. The moss is a good 1" thick. It has practically become a living roof.

When I first moved to an area where moss is prevalent in shaded areas, I thought: How picturesque! It sure looks fairy tale-like, I thought. But owning a house with moss on the roof is quite a different matter.

Recently, the neighbor whose roof is shown above had to completely replace it because of this moss--over $10,000. He has a small roof, and he contracted with a super-bargain roofing company.

Liquid or Dry Applications

I like my Pacific Northwest home, but the same directional rule of thumb that applies to trees (moss grows on the north side of trees) definitely does apply to my house and everyone else around here.

As such, due to the shorter daylight periods, moisture, and general gloom, I use moss-killer from Fall to Spring. Summer is the only season when moss does not grow.

I have used three different types of moss removal products: a liquid-sprayer application that is zinc-free and two dry, powdered substances that contain zinc:

Remove Moss or Replace Roof? Your Choice.

The cousins to home renovations are home repair and maintenance. A person remodels a house because it's no longer stylistically suitable; because it's not meeting functional needs; or because major repairs need to be made, and it turns out easier in the end just to completely remodel the thing.

No one has ever replaced an otherwise functional roof simply because it doesn't meet stylistic needs.

In most cases, roofs get replaced because they have reached the end of their natural lifespan or they have not been properly maintained.

If you maintain your roof well enough, you probably will not be replacing it. Have I driven the point home enough yet? I hope so, because now we're going to kill some moss!

How Moss Will Destroy Your Roof

Moss develops in perennially shady areas in areas that tend to be cool and damp. You can live in a cool, damp area, but sections of the roof that get a couple of hours of sun per day may not develop moss. It's that third factor--lack of sun--that promotes moss growth.

Moss begins as a thin green layer on the tops of the shingles. The areas between shingles and the shingles' edges also get moss because they are even more shaded.

As moss thickens, it will get under the shingles, acting like a jack and raising and pushing them upward. It's bad enough with asphalt or composite shingles, but if you have wood shingles it's disastrous. Wood's porous surface is prime real estate for moss growth. Once moss has adhered to wood shingles, it's tougher to get off than the relatively smoother planes of composite or asphalt shingles.

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