SHOULD YOU RESTORE THE
NATURAL COLOR OF YOUR ROOF?
The original color of a shake roof is reddish brown. This is the natural color of the inside of a cedar tree.
After exposure to the ultraviolet rays from the sunlight, the natural color turns to a silvery gray. If you cut a shake in half you will see the inside is still a reddish brown color. The lighter natural silvery gray color reflects more of the sun's rays, keeping the cooler and increasing the life of the roof.
Staining your roof to obtain the "natural" color can result in drying out the shake and increasing its flammability (due to a petroleum base). Staining will also cause the shake to absorb and retain more heat from the sun. This can result in premature splitting and dry rot.
HOW OFTEN SHOULD YOU
REPLACE THE "NATURAL" OILS
IN YOUR SHAKES?
The idea of replacing natural oils in cedar shakes has been around a long time. Until recently, this was a concept to which most of us blindly nodded our heads. Here is some of what Oregon State University Extension Service (Publication EC1271) has to say about the so called oil replacement:
"These oils account for less than 3% of the total mass ...applying replenishing oils to weathered shingles may be of questionable value... unless you include an effective mildcide or preservative, an oil-like linseed may provide an additional food source for the mold, mildew and fungi... furthermore, petroleum based products are likely to be oxidized (broken down) by sunlight, to have only a short lived effect and to increase flammability of your roof."
HERE'S HOW THERE CAN BE
SUCH A DIFFERENCE:
The shake beneath the flashing is good because the zinc leaching out on it kills the moss, lichen and fungus. The natural oils whithin the shakes are still doing fine. The reason the other shakes dried out and became brittle is not from a lack of oil in the shake, but rather an excess of growth in the shake. How often you should replace oil (barely present to begin with) which can actually encourage fungus growth, works for a short period of time and can make your roof more prone to fire?
SHOULD YOU USE A METAL
As mentioned above, the streaks you see on most roofs come from the zinc leaching out of the flashing. A metal based treatment does kill moss but it will also kill everything in its path. The run-off will not only harm the immediate plants and animals around your house, but also ends up in the ground water, streams, rivers and lakes.