Building Stairs with Landings Part 2 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
Lay out stringers on 2 x 12 lumber using a carpenter’s square. Trim off the waste sections with a circular saw, finishing the notched cuts with a handsaw. In the following illustrations, the waste sections are left unshaded. In standard deck construction, the outside stringers are fitted with metal tread supports that are attached to the inside faces of the stringers. The middle stringer in each flight of stairs is notched to create surfaces that support the stair treads—when cut, these surfaces must align with the tops of the metal tread supports. For the upper staircase stringers, notches are cut at the bottom, front edges to fit over a 2 x 4 cleat that is attached to the landing. The top of each notch should lie below the nose of the bottom tread by a distance equal to one rise plus the thickness of a decking board.
Create Final Stair Landing Layouts - Step 2
Begin construction by building the landing. On a flat surface, build the landing frame from 2 x 6 lumber. Join the corners with 3" deck screws, then check for square by measuring diagonals. Adjust the frame until the diagonals are equal, then tack braces across the corners to hold the frame square.
Create Final Stair Landing Layouts - Step 3
Using your plan drawing, find the exact position of the landing on the ground, then set the frame in position and adjust it for level. Drive stakes to mark locations for the landing posts, using a plumb bob as a guide. Install the footings and posts for the landing.
Create Final Stair Landing Layouts - Step 4
From the top of the deck, measure down a distance equal to the vertical drop for the upper staircase. Attach a 2 x 4 reference board across the deck posts at this height. Position a straightedge on the reference board and against the landing posts so it is level, and mark the posts at this height. Measure down a distance equal to the thickness of the decking boards, and mark reference lines to indicate where the top of the landing frame will rest.
Create Final Stair Landing Layouts - Step 5
Attach the landing frame to the posts at the reference lines. Make sure the landing is level, then secure it with joist ties attached to the posts with 5⁄8" x 3" lag screws. Cut off the posts flush with the top of the landing frame, using a reciprocating saw.
Create Final Stair Landing Layouts - Step 6
Remove the diagonal braces from the top of the landing frame, then cut and install joists. (For a diagonal decking pattern, space the joists every 12".) Attach the decking boards, and trim them to the edge of the frame.
Create Final Stair Landing Layouts - Step 7
For extra support and to help prevent sway, create permanent cross braces by attaching 2 x 4 boards diagonally from the bottoms of the posts to the inside of the landing frame. Brace at least two sides of the landing. Remove the temporary braces and stakes holding the posts.
Create Final Stair Landing Layouts - Step 8
Lay out and cut all stringers for both the upper and lower staircases. For the center stringers only, cut notches where the treads will rest. Start the notches with a circular saw, then finish the cuts with a handsaw. Measure and cut all tread boards.
Create Final Stair Landing Layouts - Step 9
Use 3⁄4"-long lag screws to attach angle brackets to the stringers where the treads will rest, then turn the stringers upside down and attach the treads with lag screws. Gaps between tread boards should be no more than 3⁄8".
Create Final Stair Landing Layouts - Step 10
Dig and pour a concrete footing to support each stringer for the lower staircase. Make sure the footings are level and are the proper height in relation to the landing. Install a metal J-bolt in each footing while the concrete is wet, positioning the bolts so they will be offset about 2" from the stringers. After the concrete dries, cut 2 x 4 footing cleats, drill holes in them, and attach them to the J-bolts using nuts.