How to Build Continuous Stair Rails

Measure the length of the wall along your stairs with a measuring tape. Measure diagonally, following the line of the stairs along the trim just above the treads where the steps meet the wall. Have an assistant hold the measuring tape 3 inches before the nose of the top step and measure to the point where the trim bends to join the baseboard. Cut a piece of rounded railing stock to that measurement, plus 4 inches. Keep in mind that wood used for stair railing can be no more than 1 1/2 inches in diameter.

Mark the inside edge of the railing 2 inches from each end. Place the railing in a miter box and cut each end at a 45-degree angle, angled out toward the outside edge of the rail. The miter arm should be set so the saw hits the 2-inch mark at the inside angle of the cut.

Swap the 2-inch piece cut from the top of the railing for the one from the bottom. Dry fit the angled cuts of the pieces to the cuts on each end of the railing to form perfect 90-degree elbows with returns that are 2 inches long, measured from the inside of the elbow.

Apply wood glue to the cut surfaces. Drill 1/8-inch pilot holes through the return into the railing and nail the returns to the cut angle of the rail with 2-inch finishing nails.

Measure the length of the handrail bracket from the bottom mounting hole to the end of its arm. Add the depth of the handrail.

Run a stud finder along the wall of the staircase and locate at least three studs along its length -- one at the top, the bottom and as near the middle as possible. Studs are usually 16 inches apart. Mark the center of each stud at a comfortable point from 34 to 38 inches high -- minus the length of the bracket and depth of the rail -- measuring from the top of the tread.

Drill a pilot hole into each stud at the point marked and install the bottom of the bracket with the included screws and appropriate screwdriver.

Lay the rail so it rests on the top of the arms of the brackets, positioning it so the returns are snug against the wall. Screw the underside of the rail to the brackets with the included U-shaped fittings designed to hold it to the arm of the bracket.

Make any adjustments necessary to the positioning of the bracket and fasten the remaining screws through the upper mounting holes in the brackets. Each bracket usually has three mounting holes.