Building a staircase step by step
Building a staircase can be tricky, given its three-dimensional characteristics. Luckily, adopting a consistent installation method and following a few proven steps can cut down on the potential for errors.
Also, an occasional pause to review your work and consider the remaining installation steps can be very helpful until you have a few successful stairwell installations under your tool belt.
By their very nature, staircases can be hazardous for the elderly and infirm. That’s why they tend to be subject to much stricter building and safety code regulations than other aspects of a residential or commercial structure. Start building a staircase by reviewing local ordinances to make sure your proposed plan is in compliance before getting started.
In addition to being tricky, building a staircase is by their nature, inherently hazardous for builders as well. At minimum, the building process is a two-man job. And you’ll need sturdy ladders or scaffolding to keep things safe while working between the two floors being bridged.
Building a staircase here is fairly straightforward: a simple, three-runner design. Because this is not a public-use staircase, a straight set of stairs with no split-level landing was specified.
Building a staircase – Step 1
Start building a staircase by measuring the area you have to work with. This will give you a good idea of how large or compact your staircase needs to be. Key considerations here include determining the rise of the staircase, the run (total number of steps needed in the staircase), the overall width of the staircase and the amount of headroom clearance required.
Select the starting point for the staircase, making sure it will not obstruct any air vents, electrical sockets or similar obstacles. It’s also a good idea to take a moment and consider future foot traffic patterns once the building is complete to reduce the potential for collisions and congestion. (This is especially important for commercial stairwells in restaurants and similar venues.)
Once you’ve settled on your starting point, have a helper on a ladder mark the second-story landing point and use a chalk or pencil line to lay out both the angle and height of the staircase. The first and second-story landing points, or stringers, are where the runners will attach.
Stair risers and treads are dictated by building code, so you’ll have to check your local code before proceeding with this step. For this build, we used 17 steps, or treads, placed 7 inches apart − a measure we feel is ideal for residential stairs.
Many staircases have only two runners. But we like the additional stability and durability provided by a third, center-placed runner. All three runners will be cut from 20-foot 2×12 pieces of treated yellow pine.
Inspect the boards to be used as runners making certain they are absolutely straight, no warping or splitting. You can purchase pre-cut risers at your local Home Depot store. If you opt to cut them yourself, you will gain accuracy and consistency (and speed the marking process) by using a framing square and a pair of stair gauges.
Clamp the gauges to the square at the desired run and rise dimensions, and mark the first intention. Then slide the square down the board to mark the second and so on. Use a circular saw and cut out the intentions, or sliders, that will hold your steps in a dragon-tooth pattern.
In this staircase installation, the measurement worked out to seventeen 10-inch x 7-inch cuts on three runners. Remember to measure and compensate for the sliders at the base and landing of the stairs.
Next, cut the treads and risers for the staircase. Treads need to be sturdy and long-lasting. For this stairwell installation, we used the same 2×12 yellow pine boards, while opting for cheaper OSB for the risers.
Cut both the treads and the risers to their desired dimensions. In this case, the steps were 10 inches deep and 46-3/8 inches across. A table saw is ideal for these cuts.
Remember, a straight staircase will always have one fewer stair step then risers. This is to account for the final rise at the top of the stairs to reach the second-story landing.
Many staircases use two runners. On this job, however, the contractor elected to use three runners on this high-traffic staircase to give it extra stability and durability. But whether you opt for two or three runners, the tricky part now begins: getting everything properly aligned and attached in place. Using a level is absolutely vital during this portion of a building a stairwell. Be prepared to use it often.
Start by positioning the runners in their respective locations and then check to insure horizontal alignment across them using a 4-foot level. The runners must be absolutely plumb and level. Even a difference of 1⁄4 inch is sufficient to throw the entire staircase out of alignment. A good tip is to simply tack the runners into place and re-check them with your level to confirm proper alignment before final attachment to the frame.
Using the level, check the runners at the bottom, center and top of the staircase and make any adjustments needed before attaching them to the wall studs. Once you’re satisfied with their placement, attach the outer runners to the wall studs, the subfloor at the bottom of the staircase and the landing at the top using 16p nails.
If you opt to use a third runner in the center, as we did, begin by attaching it at the top and bottom of the staircase, as you did with the two outside runners. Again, use your 4-foot level, placed across all three runners at various points on the staircase, to make certain the third runner is level and plumb from top to bottom.
Obviously, you won’t be able to attach this third runner directly to any side framing for additional support. Instead, cut a length of sturdy yellow pine from your 2×12 boards and attach it halfway between the top and bottom of the stairwell to the bottom side of the runners.
Attach this board to all three runners and to the framing on each side. This will reduce any eventual sag in the staircase and make it tighter and quieter over many years of hard use. Then attach the third runner to the subfloor and landing. Once again, use 16p nails for this process.
Once the runners are in place, you’re ready to install the treads and risers. Start at the bottom by applying a good quality construction adhesive to the runners. It doesn’t take much adhesive to secure a tight hold.
Generally a ½-inch bead in the center of each slider is sufficient. This will help hold both treads and risers in place and reduce squeaking and creeping as the staircase ages. Once your adhesive is in place, attach the step and riser using 16p nails. Repeat this procedure all the way to the top of the staircase.
–By Jack Roberts, builder and remodeler