Installing a new roof lead inevitably to moments of discovery. The western half had not been re-roofed in a long time, and although there were no underlying shingles, there was also no underlying sheathing or waterproofing. Some of the boards were as much as 18 inches wide. Gaps between boards had been infilled with wood strips, but many of the old boards were badly split and broken. Needless to say, we installed new OSB over the old boards, before proceeding to install new asphalt shingles.