Q: Can we install outdoor light fixtures over cedar lap siding? I'm afraid there will be ugly gaps between the back of the fixtures and the house.
—Pam Kushnir, Apollo, PA.
A: Anything destined for an outside wall—light fixtures, outlet boxes, and dryer vents—should be attached to a mounting block that rests against the sheathing to keep water from getting past the fixture and underneath the siding.
The trick is to make this attachment weatherproof so that no water reaches the sheathing. Here's how to go about it.