A.Cyrus Miller, production supervisor for Common Vision Inc. in Hamden, Conn., responds: Beveled siding will not bend properly around your curved walls because of the gap created by lapping each piece over the piece below. You are, in effect, increasing the circumference of the wall at the lap. Your clapboard is tight to the sheathing at the top of the board (the thin part) and therefore is a true 4-ft. 8-in. radius. At the bottom, however, the lap means you are bending around a 4-ft. 8 1/4-in. radius. What happens is that the ends of the clapboard rise above the horizontal course line if you keep the board tight to the sheathing, or you get a gap between the sheathing and the top edge of the clapboard.
I have found two ways to deal with this without soaking or steaming the wood. The easiest is to use a non-beveled rabbeted siding — one that makes full contact with the sheathing across its back, not just at the top edge (see illustration). Since most rabbeted sidings come in 3/4-inch thickness, you may have to have this milled in 1/2-inch stock...
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