How to Build a Deck With Tongue & Groove Lumber

Lay out the deck area with stakes and builder's twine. Square the outline by measuring with a tape measure from corner to corner and moving the stakes until the measurements are identical. Rake the area clear of leaves or other debris. Slope it slightly on all sides away from the center so water does not stand under the deck. Lay a waterproof membrane secured with gravel for added moisture protection.

Mark locations for piers at the four corners, and every 8 feet in between for a big deck. Dig holes for precast concrete piers with a posthole digger, 2 feet deep or below the frost line. Buy piers with metal beam brackets installed. Set them in the holes and plumb them with a level. Lay a board on the brackets and level the tops, but allow a slope of at least 1/4-inch per foot to drain water from the deck.

Set 4-by-4-inch beams in the piers on two sides. Fasten them with galvanized screws and a screw gun through the holes in the brackets. Set a 2-by-6-inch band board on the outside edge of each beam with a 2-inch edge down, and toenail it to the beam with 16d framing nails driven diagonally with a hammer.

Measure between the inside edges of the band boards and cut 2-by-6-inch joists to fit. Lay out joist locations on the two band boards. Measure 1 1/2-inches from an end and mark a line for the first joist. Measure 15 1/14 inches from the end and mark another line for the outside of the second joist. Mark 16-inch intervals based on that second line to locate other joists. Mark both sides.

Nail joists in place through the band boards with framing nails, at least two nails in each joist end, with each end of a joist sitting on top of half of the 4-by-4-inch beam. Nail band joists between ends of the rim joists on both ends, to make a square frame.

Prefinish the edges and bottoms of the tongue and groove lumber with stain, preservative or paint to seal it against moisture. Let this dry overnight. Rip the groove off one side of the first flooring board with a table saw. Lay the board across the joists with the edge 1-inch over the outside band board and the tongue edge in. Nail it to the joists with 8d galvanized nails. Put a framing square on the ends to make sure the first board is square with the deck frame.

Slip the groove of the second board over the tongue of the first board. Tap it securely in place with a block of wood against the tongue, using a rubber mallet. Nail this board to the joists with 8d nails driven diagonally through the tongue. Use nails with a finishing head and drive them flush with the wood so they do not block the next groove.

Work across the deck with boards. Use a square every couple of boards to ensure the flooring stays square; adjust a board slightly, if necessary, if boards start to slip out of square, as may happen because of irregularities in the lumber. Measure the width for the last board and rip the tongue off with the table saw, to allow for a 1-inch overhang. Nail that board to the joists through the face.