There are a couple of things to look for when deciding on having your cedar shake roof cleaned. The most important thing is are the cleaners going to walk on your roof? If the answer to this question is yes, BEWARE! The methods of walking on a cedar shake roof involve damaging claw slip over shoes do no nothing but damage the shakes on your cedar roof.
One of the next things to watch out for are the false repairs being done to cedar shakes. Most roofs that have cedar shakes are built in such a way, that a homeowner would not typically be able to see if there was damage being done. So to make a bogus repair and call it day can be easy money for someone trying to take advantage of you.
If you, the homeowner, is having a company come out and clean or do maintenance on your cedar shake roof, beware of anybody that is nailing down your cedar shakes. Cedar shakes have a natural 3% oil, that is drawn out over time from the sun. If this oil is not reintroduced back into the cedar shakes, they will dry out and begin to curl. It is essential that INSTEAD of nailing down the shakes (which is wrong anyway), that the cedar is handled in a much more delicate manner. Our company uses chicken ladders to access parts of the roof that need repair, and we do not nail down the front of your shakes to avoid curling. Once the shakes are rehydrated, the ones that do not lay back now, get replaced the correct way.