How to Lay Out Stair Stringers for a Deck

Mark your run dimension on one leg of a framing square and the rise dimension on the other with black electrical tape. Lay the framing square at one end of the first stringer so the marks created by the tape are flush with the edge of the stringer.

Outline the rise and run for the first step on the outside edge of the framing square with solid dark lines. Continue marking subsequent steps. Add dotted lines to represent the outline of the actual tread that will rest on the cleat, based on your measurements of the tread. Typically a deck board, measuring either ¾ or 1 inch thick, can be used for the stair tread.

Mark the bottom of the stringer to denote a cut to allow it to rest flat on either the ground or a cement pad. Mark the top to note a cut where the stringer rests against the deck’s rim joist. Cut the wood along these marks with a circular saw. Repeat the process in steps 1 through 3 to create a second stringer that's a mirror of the first.

Screw galvanized cleats at the bottom of each outline of a tread with 1 ½-inch lag screws. Screw galvanized angle brackets to the top of the stringers to prepare them for installation on the deck.