What Causes Your Cedar Shake Roof to Deteriorate?
It gets “OREGONIZED.” When wood is exposed to the effects of sunlight and moisture, its surface begins to change. This change is both physical and chemical and is commonly called weathering. The color will change first. The initial change from reddish-brown to silvery gray is the result of the ultraviolet rays from the sun. This usually happens fairly quickly – well within the first year. Gradually the roof will take on a darker gray color. This indicates that your roof is being colonized by microfungi. Your roof is steadily becoming “OREGONIZED.”
As the Roof Continues to Age
The surface and sharp edges are eroded by abrasive particles carried by wind and water, and by continued exposure to heat and cold. Wood destroying organisms continue to slowly degrade the shingle’s surface and edges. The roof no longer looks new. Debris from trees may be accumulating in the valleys and between the shakes. After each rain, these areas will remain moist longer. Because of the moist conditions, other plants soon begin to grow, primarily lichens and mosses. Your roof is now “OREGONIZED” and its deterioration will rapidly accelerate.
Moss & Fungus Growing on Your Roof Does Double Damage
(1) During rain, it retards the shedding of water, which promotes leaks, and (2) After the rain stops, it prevents the surface from drying, which further encourages the growth of wood-rotting organisms.
Leaves, needles, and other debris which is allowed to accumulate has these same two harmful effects. In addition, the debris increases the fire danger to your roof. There are several ways you may choose to deal with this debris and I would be glad to go over them with you. The point is, you must deal with it or your roof will rot away at a surprising rate.