During the elaborate deck build at my own property years ago, it became obvious quite quickly that prefabricated stair stringers that could accommodate my design would not be easily found. As such, every single one of them was hand-cut on site, from 2x12 treated lumber. This custom stair stringer process has also been adopted when building decks for hire and I wouldnt have it any other way.
Most deck designs accentuate the aesthetic throughout, which entails a finished look along the front face of all stairs, and a decorative stringer along the sides. Unfortunately, pre-fab metal stringers do not easily allow such finishing, as there arent any vertical surfaces upon which fascia or outer decorative stringers can be mounted. And although pre-fab lumber stringers are readily available in many lengths (stair denominations). The run of these stringers is preset to a depth that does not cater well to the majority of my stair and deck designs.
The standard rise (height) of a deck stair tends to match the standard height of any stair – seven-and-a-quarter inches. The run (depth) of a standard stair is usually about nine-and-a-half inches. However, it has been my experience that the run of a decking stair is much more pleasant to use, and visually appealing when closer to 11.5 or 12-inches. This is the main reason why cutting stair stringers on site is optimal. An 11.5-inch stair run allows tandem 2x6 boards along the top of each stair, in lieu of a single 2x10 for a nine-and-a-half inch run.
Creating stair stringers is fairly easy, once the process is established. Using a 90-degree right angle square, the edge of a 2x12 is marked where the seven-and-a-quarter inch line is along the short side, and the 11.5-inch line on the long side. The right angle is then traced onto the board. The angle square is then shifted down until the long mark meets the short mark, and the right angle is again traced. This is repeated for the number of stairs required on the stringer. Along the bottom stair tracing, the length of the run is shortened by one-and-a-half inches, to allow for a bottom faceplate without disrupting the stair depth. A nailer is fastened to the stringer tops, and along the bottom. This allows for a rigid section of stair stringers that can be properly mounted to the deck frame directly below the outer perimeter, while maintaining a solid section along the bottom stairs under which small concrete pads are used for support, and leveling.
When stairs meet at an angle, and wrap to another side, the process is similar. However, the length of the run will increase to accommodate for the miter of the angle. The length of each stairs run will depend upon the angle of the stair wrap. Typically, its easiest to pre-build the straight stair sections first, in order to help determine the run length at the angled area. It can be challenging, but the results are well worth the effort. It involves a bunch a mathematics, that can then be verified hands-on.
Once the stair stringers have been successfully placed, mounted, and permanently affixed to the main structure, the tandem 2x6 stair tops are typically added before the main decking occurs. This of course allows easy topside access to the deck for the main 2x6 top-decking installation. Once the tops have been installed throughout, 2x8 boards are then fastened along the fronts as fascia, mitered are every corner to match the tops along the wrap-around stairs, and main deck perimeter. The installation process of course gets even more complicated when the deck design itself boasts multiple tiers. Although every deck is different, the process is relatively the same.
No matter the design, an intricate stairs layout will easily become the focal point upon completion. And with stairs that wrap along the perimeter of the deck, the need for railings greatly diminishes. In some instances, stairs throughout act as incidental seating, especially when the deck faces a firepit or lakefront. By maximizing the use of stairs thereby minimizing the need for railings, the view from the deck is also greatly improved as there are no obstructions no matter where you are on the deck.
Custom stringers take practice. Even now, the first stringer is cut successfully serves as the template for the remaining similar stringers. When building a multi-tiered deck, it isnt uncommon to have several stringer templates. Nonetheless, it is always a fun adventure creating custom stringers on site. Although laborious, it sure beats trying to find ones off-the-rack, that will only kind of work. The deck you want deserves a hands-on approach, stairs included.