How to Install a Deck Against Siding

Determine what type of deck planking you are using and read the manufacturer’s guidelines for specific instructions on spacing against the termination point of the house. Different deck materials have different spacing requirements, with the average gap required being between 1/8 inch and 1/4 inch. Use 1/4 inch if in doubt, but understand that manufacturer’s guidelines always trump installation preferences.

Lay a full deck board along the outside edge of the deck away from the home, which is the most visible area. Lay the deck board down across the deck joists so that it spans the distance between them. If the board terminates in empty space between two joists, you need to cut the board off where it crosses the last joist so that it splits the joist and can share the same joist with the next board in the row. Cut the ends off with the miter saw.

Nail the boards in place across the deck joists. Use the nail gun. Keep the nails at least 1/2 inch away from the outer edges of the boards so you don’t split the wood. Nail the deck boards down onto the floor joist. Nail your first row down along your starting area. Place a second row back from the first row, spacing the boards out at least 1/8 inch, or according to manufacturer preferences.

Work your way back row by row until you reach the house where the deck needs to butt up against the siding of the home. Measure the width of the gap to see if it is the same size across the length of a board, or if you need to angle the cut. Remember that you need to subtract the width of the manufacturer’s recommended joint between the cut edge of the board and the actual siding to provide space for movement.

Place those measurements on a board, with a measurement on each end of the board. Snap a chalk line between the two marks to give you the actual line of the cut across the length of the board. Set the depth of your circular saw to the thickness of the deck planking. Cut the piece of deck material along the length of the chalk line and install the piece of wood as you did the other deck planks.

Caulk the gap between the deck boards and the house siding if the manufacturer calls for it, or you can leave it open. The gap is necessary because all materials swell in the heat of the summer in what is known as seasonal expansion, and if no space is left, the deck will press against the siding and cause it to crack or the deck boards to buckle.