In Portland over the last 25 years, homeowners have repeatedly told us that they want their roofs to look good, work right, and last longer. Using that as our premise, here is the problem with moss buildup on your tile roof…
Of course, the first issue is appearance. Compare a moss-ridden tile roof to a clean, well-maintained tile roof….you make the call. Most of the reasons for a tile roof are for the beauty and longevity with no hassles to the homeowner. Let’s face it, the appearance of your home says a lot about you, and since your roof makes up 1/3 to 1/2 of your home’s appearance, having a good looking, well working roof is a top priority in Portland, Oregon. The only time function takes over 1st place is when a client is concerned about a leak.
All roofs are designed and engineered to traffic water vertically (down the roof). When moss is allowed to grow and tree debris is allowed to accumulate the growth and debris diverts the water horizontally.
Leaks caused by high winds, or a puncture from a falling tree limb is just another day in your roof’s life in Portland. But 95% of all other leak calls that seem to develop out of nowhere are generally caused by the buildup of moss and/or tree debris.
Another leak issue with tile roofs is that as moss and debris sloughs off, it falls into the valleys (drain areas that carry a lot of water off your roof). Unfortunately, most tile roofs installed in the Portland area used a closed valley system because some people think it looks better than an open valley. After fixing hundreds of tile roofs and their valley failures, I think that the problems caused by using a closed valley far outweigh how it looks. As the moss matures, it dies and falls into the valleys and other flashings. As the decaying matter builds up under the closed valleys of your tile roof, a lot of water is fed into the attic and ceilings of your home. This is when you call us and say, “I don’t know what happened it just started leaking.”
The best advice I can give you to extend the life of your roof, is to maintain your roof no matter its type or age, and you will receive in return a roof that will keep you as dry as possible and will do it for a long time.
Do you have a roof question? Leave it in the comments and we’ll include it in a future blog post.