Q: "I just had my garage sided with white cedar shingles. I want them to turn a lovely light gray, like shingled houses by the shore. Will misting them once a month with seawater do the trick?"
—Barbara Collins, Burlington, Vt.
A: I don't know; it might. Salt water does discourage the mildew that turns raw cedar black, but you will have to go on spritzing indefinitely to keep mildew at bay. Not only that, the salt will kill foundation plants, and unless you had the foresight to use copper or lead flashing, and stainless-steel nails, it will corrode any exposed metal.
If it were my garage, I'd brush on Bleaching Oil (cabotstains.com), a lightly pigmented oil stain with oxidizing agents that gradually, over the course of a year, turn cedar shingles an even driftwood gray. We used it with good results on the Manchester TV project. Read more about bleaching oil in All About Exterior Stain.