Are oil based products any good for the roof?
There are a variety of options available for topical treatments. Refer to the CSSB's Care and Maintenance Brochure for the full guidelines available from this organization. Keep in mind that the CSSB does not recommend brand names of products.
I have a cedar roof on my home and it was recommended I have the shakes oiled. Is this a good idea?
In humid areas oiling shakes does not allow them to breathe and they cannot dry out properly which could shorten their life span. The CSSB recommends you try a good fungicide/preservative. Keep in mind that no by-products, such as motor oil, should be used on cedar roofs. Hot, dry climates tend to accept oils better than moist/humid climates, simply due to the fact that oils can seal unwanted moisture into the roof. Please see the CSSB's Care & Maintenance Brochure.