Building Stairs with Landings Part 3 of 3
A landing functions essentially as a large step that interrupts a tall stairway. For the builder, the landing provides a convenient spot from which to change the direction of the stairway. For the homeowner, the landing provides a spot to catch your breath momentarily while climbing.
Designing and building a stairway with a landing can be one of the most challenging elements of a deck project. Precision is crucial, since building codes have very exact standards for stairway construction. To ensure that the steps for both the top and bottom staircases have the same vertical rise and tread depth, the landing must be set at the right position and height.
Even for professional builders, designing a stairway layout is a process of trial and revision. Begin by creating a preliminary layout that fits your situation, but as you plan and diagram the project, be prepared to revise the layout to satisfy code requirements and the demands of your building site. Measure your site carefully, and work out all the details on paper before you begin any work. Accuracy and meticulous planning will help ensure that your steps are level and uniform in size.
Remember that local building codes may require handrails for any stairway with three or more risers.
The goal of any stairway is to allow people to move easily and safely from one level to another. When designing a deck stairway, the builder must consider the vertical drop—the vertical distance from the surface of the deck to the ending point; and the span—the horizontal distance from the starting point to the end of the stairway.
During the planning stage, the vertical drop is divided into a series of equal-size steps, called rises. Similarly, the horizontal span is divided into a series of equal-size runs. On a stairway with a landing, there are two span measurements to consider: the distance from the deck to the edge of the landing, and from the landing to the end point on the ground. In general, the combined horizontal span of the staircases, not counting the landing, should be 40% to 60% more than the total vertical drop.
For safety and comfort, the components of a stairway must be built according to clearly prescribed guidelines, as listed in ‘Anatomy of a Stair with Landing’.
Anatomy of a Stair with Landing
The challenge when planning a stairway is adjusting the preliminary layout and the step dimensions as needed to ensure that the stairway fits the building site and is comfortable to use.
Rises must be no less than 4" and no more than 8" high.
Runs, the horizontal depth of each step, must be at least 10". The number of runs in a staircase is always one less than the number of rises.
Combined sum of the step rise and run should be about 18" to 20". Steps built to this guideline are the most comfortable to use.
Variation between the largest and smallest rise or run measurement can be no more than 3⁄8".
Stair width must be at least 36" so two people can comfortably pass one another.
Stringers should be spaced no more than 36" apart. For added support, a center stringer is recommended for any staircase with more than three steps.
Landings serve as oversized steps; their height must be set as precisely as the risers for the other steps in the stairway. Landings should be at least 36" square, or as wide as the staircase itself. U-shaped stairways should have oversized landings, at least 1 ft. wider than the combined width of the two staircases. Landings very often require reinforcement with diagonal cross braces between the support posts.
Concrete footings should support all stringers resting on the ground.
Create Final Stair Landing Layouts - Step 1
Attach a 2 x 6 nailer to the landing to support the center stringer (page 130), then set the staircase in place, making sure the outside stringers are flush with the top of the decking. Use corner brackets and joist-hanger nails to anchor the stringers to the rim joist and nailer. Attach the bottoms of the stringers by nailing them to the footing cleats.
Create Final Stair Landing Layouts - Step 2
Measure and cut a 2 x 4 cleat to match the width of the upper staircase, including the stringers. Use lag screws to attach the cleat to the rim joist on the landing, flush with the tops of the joists. Notch the bottoms of all stringers to fit around the cleat (see Construction Details), and attach angle brackets on the stringers to support the treads.
Create Final Stair Landing Layouts - Step 3
To support the center stringer at the top of the staircase, measure and cut a 2 x 6 nailer equal to the width of the staircase. Attach the nailer to the rim joist with metal straps and screws.
Create Final Stair Landing Layouts - Step 4
Position the stringers so they rest on the landing cleat. Make sure the stringers are level and properly spaced, then toenail the bottoms of the stringers into the cleat, using galvanized 16d nails. At the top of the staircase, use angle brackets to attach the outside stringers to the rim joist and the middle stringer to the nailer.
Create Final Stair Landing Layouts - Step 5
Measure, cut, and position tread boards over the angle brackets, then attach them from below, using 3⁄4"-long lag screws. The gap between tread boards should be no more than 3⁄8". After completing the stairway, install railings.