Installing Tongue and Groove
Tongue and groove siding can be installed horizontally or vertically. In horizontal application, start at the bottom and work up with the groove edges facing downwards. Siding up to 6 inches wide can be blind nailed with one siding nail per bearing toe-nailed through the base of each tongue. Wider siding should be face nailed using two nails per piece. Nails must penetrate 1¼ inches into solid wood.
In vertical application, start at one corner with grooved edge toward the adjacent wall. Use a level or plumb line to ensure that the first board is installed plumb. The grooved edge of the first board may have to be trimmed to ensure a flush fit. Siding is nailed to horizontal blocking lines installed between studs or to furring strips. As with horizontal installation, pieces up to 6 inches can be blind nailed and wider pieces should be face nailed.