Stair Stringers – How to Build Up Instead of Cutting Them Out
stairs
I'm thinking of building a stair stringer using a 2×6 and reclaimed wood triangles.
How to fix the triangles on the base, long screws, nails?
Best Answer
Fastening the wood triangles to the 2x6 can be done in a number of ways such as glue and dowel rods as suggested in another answer. The addition of a plywood scab on the side as suggested in a comment is even better.
But also consider that as drawn in your picture the construction of a stairway with triangles cut at 45 degrees would produce a stairway with narrow steep steps such as you might find in some house built 120 years ago. Modern stairways are built with the rise of each step less than the run of each step. If you were cutting your triangles out of reclaimed 2x6's (which are 5.5 inches wide) you would want to cut them more like the right hand side of the below picture.
The angles and dimensions as shown to the right above are only an example and may very well not be exactly correct for your application or even within the range of code standards for stairs. Keep in mind that the design of a stairway requires careful calculations, taking tread thickness and flooring thickness at the head and base of the stairs into account so that all the steps are a uniform size. Uniformity is important for building code compliance and safe usage of the stairway.
Given that your stringers are going to be about 8" wide, you'll be fine with some pretty thin stuff. Heavy Jeep frames from the 1970s were only about 3/16" thick, and only about 4" wide. I've seen truck frames around 1/4" by 8", but they were larger single-axle agricultural trucks. Really large single-axle trucks only have about 1/2"-thick steel frames.
Come to think of it, I've walked stairs made with no heavier than 3/16" stringers in penitentiaries. They felt nearly like STONE.
If you're concerned about racking, remember that every tread will act as an anti-rack brace. Until your treads go on, the stringers will feel pretty flimsy if you push them sideways. AFTER the treads go on, they'll be train-wreck rigid.
One approach is to pry up one of the tottering edges up slightly and inject exterior construction adhesive (some are rated for stone/masonry) a few inches in and staying well away from the outside edges. Then lower the stone and let it dry undisturbed.
When dry, this creates an adhesive wedge. Its sticking power is less important than its shape.
Obviously, if rearrangement or removal of the stone is someday needed, this makes it a bit more difficult, but not impossible.
However, if you think the problem is progressing, you need to address the underlying erosion problem before taking this step.
Best Answer
Fastening the wood triangles to the 2x6 can be done in a number of ways such as glue and dowel rods as suggested in another answer. The addition of a plywood scab on the side as suggested in a comment is even better.
But also consider that as drawn in your picture the construction of a stairway with triangles cut at 45 degrees would produce a stairway with narrow steep steps such as you might find in some house built 120 years ago. Modern stairways are built with the rise of each step less than the run of each step. If you were cutting your triangles out of reclaimed 2x6's (which are 5.5 inches wide) you would want to cut them more like the right hand side of the below picture.
The angles and dimensions as shown to the right above are only an example and may very well not be exactly correct for your application or even within the range of code standards for stairs. Keep in mind that the design of a stairway requires careful calculations, taking tread thickness and flooring thickness at the head and base of the stairs into account so that all the steps are a uniform size. Uniformity is important for building code compliance and safe usage of the stairway.