Simple Deck Stairs Installation
Updated: Apr 4, 2019
Deck stairs can remain natural wood or be painted to suit your preference.
Deck stairs, also known as steps, provide a convenient transition from a yard to a deck or from the deck to an exterior door. For a yard, it’s necessary to install a concrete pad as a base for the steps. For an exterior door, the upper end of the steps attaches to the house and the lower end attaches at the deck. As long as the transition from the deck to the next level falls within the minimum code requirements, you can build a set of steps using materials and a stair-cutting guide that you find at home centers if you have basic carpentry skills and the right tools. As with many home-improvement projects, building a simple set of deck stairs starts with taking some measurements.
Determine the rise, or vertical distance, of each step by measuring down from the surface of the deck to the yard. Alternatively, measure up from the deck to the underside of the threshold at an exterior door. Divide the measurement by 7 inches, which is the standard height of a single step. If necessary, adjust the rise by increments of an inch until the result works out evenly. For example, if the overall rise is 30 inches, you will build four steps, and each step will have a 7½-inch rise, as opposed to 7 inches.
Use the number of steps to determine the run of the steps, which is the distance the steps extend out from the edge of the deck or the side of the house. For example, for four steps made of two 6-inch-wide deck boards laid edge to edge, the run will be 48 inches, or 4 feet from the edge of the deck or house.
Determine the length of 2-by-14-inch construction grade redwood or fir board needed to make the stringers that support the treads of the steps. In this example, each stringer will be 4 feet in length, plus 6 inches to allow for angle cuts at the upper and lower ends of each board.
Determine the number of stringers you'll need, based on the overall width of the steps. Stringers should be spaced no more than 24 inches apart for maximum support. For a set of steps 48 inches wide, you will need a stringer at each side and one in the center. For 60-inch-wide steps, use four stringers.
Cutting the Stringers
Begin by marking and cutting the notches in one stringer that will be used as a pattern for the rest. To do this, place a length of 2-by-14-inch redwood or fir flat on sawhorses. Refer to the stair-cutting guide and mark the cutouts for the steps based on your rise and run determinations, using a framing square. The guide will tell you that rise measurements are on the short leg of the square and run measurements are on the longer leg.
Refer to the guide and use the square to mark the plumb, or vertical cuts, at the upper and lower ends of the stringer. Finally, mark the level cut where the lower end of the stringer attaches to a concrete base or the deck.
Put on safety glasses. Cut out the notches for the steps with a circular saw and a framing blade. Cut the vertical marks at each end and the level mark at the lower end.
Place the stringer flat on another piece of 2-by-14-inch lumber. Align the straight edges of both and mark the second stringer. Set the pattern aside and cut the next stringer as before. Repeat this to mark and cut the remaining stringer or stringers based on the width of the steps.
Installing Stringers and Treads
Measure down 1 1/2 inches from the surface of the deck at the area where the stairs install, and mark the rim joist at this point. Alternatively, measure down from the underside of a threshold and mark the siding on the house. Use a 4-foot level as a guide and mark a level line as a reference for the upper ends of the stringers.
Determine one side of the stairs as a starting point. Fit the vertical cut at the upper end of a stringer against the rim joist or house, and align the uppermost corner of the stringer at the level reference line. Attach the stringer to the rim or house using 1 1/2-by-6-inch framing angles at the inside corner where the stringer meets the rim joist or house. Drive 5-penny common nails at each of the provided nail holes in each leg of the framing angle, using a hammer.
Measure across from the outer edge of the installed stringer, and mark the level line at the width of the stairs. Install the stringer at the opposite side of the stairs, using another framing angle and nails at the inside corner, as before. Use the level line as a guide to install the remaining stringer, or stringers, evenly spaced between the outer stringers.
Determine the amount of overhang for the deck boards that make the treads at each step, such as 2 inches. Alternatively, the outer ends of the boards may be even with the outer faces of the stringers at each side.
Count the number of steps and cut two pieces of 2-by-6-inch redwood deck boards to the desired length to serve as treads for each step. Mark the pieces for cutting with the framing square to ensure the ends will be square and uniform. Make the cuts with the circular saw.
Start at the lower end of the installed stringers. Place one of the deck boards flat across the first step and fit the rear edge against the face of the vertical riser cuts at the rear of the step. Align the piece so the ends and any overhangs are uniform and even. Attach it by driving a pair of 3-inch deck screws, evenly spaced from front to rear, through the tread and into the corresponding stringer, using a screw gun.
Place the second board across the first step and align the ends as before. Position it to allow a 1/2-inch gap between its inner edge and the outer edge of the installed piece. Attach it with pairs of screws at each stringer.
Repeat the procedure to install the remaining deck boards on the remaining steps.
Things You Will Need Measuring tape Saw horses 2-by-14-inch construction grade redwood or fir planks Framing square 4-foot level 1 1/2-by-6-inch metal framing angles 5-penny common nails Hammer 2-by-6-inch redwood deck boards 3-inch deck screws Screw gun Tips Check with the local building department to determine the minimum code requirements for your locality. Many localities require handrails when a transition exceeds a particular footage, such as 32 inches above ground. Talk to a sales representative about using stair gauges that fit onto the legs of a framing square and reduce the time needed to lay out and mark the stringers.For attaching stringers at a stucco or masonry wall, use 3-by-6-inch framing angles that have predrilled holes for bolts. Secure the angles using 2-inch lag bolts and expanding anchors or whatever local code mandates.
About the Author
William Machin began work in construction at the age of 15, while still in high school. In 35 years, he's gained expertise in all phases of residential construction, retrofit and remodeling. His hobbies include horses, motorcycles, road racing and sport fishing. He studied architecture at Taft Junior College.
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