If you have a wood roof, it’s more than likely a ½ inch #1 cedar shake. They usually are the lowest grade in the #1 grade arena for cedar shake roofing materials. In the trade, they’re known as “builder’s grade” because they are very economical for building entire housing developments.
These types of shakes require repair and treatment every five years to help them last 30-35 years. If left unattended and un-maintained the average shake roof will start causing you problems at about 12-15 years, if not replaced.
After 2-3 years in Portland, a heavy growth of fungus covers the wood roof and at about 5 years of age the moss sets in pretty heavy. This growth really makes the shake roof look unkempt and is unsightly for 9 months out of the year during our rainy seasons.
You’re probably wondering why people use shakes if this is happening to their wood roof. The truth is they look pretty good when they are less than 5 years of age and they represent quality and help sell the home. They are also a renewable resource and take very little energy to produce compared to other roofing products while providing twice the insulating value.
So, if you have a home that has a builder shake and you want it to look better and last longer you’ll need to keep it blown free of tree debris (once every year depending on amount of tree fall) and repair and treat the roof once every five years.