Tips for Buying and Using Rough Lumber Buy smart to get the best deals and the best wood. By Tim Johnson Start out thick Rough lumber thicknesses are measured in 1/4-in. increments. The thinnest rough-cut boards, labeled 4/4, and called four quarter, are 1-in. thick. It’s tough to get surfaced stock thicker than 13/16-in. from 1-in. rough stock. Plan to lose 3/16-in. (1/4-in.on thicker stock) when you plane a roughsawn …