We are currently on few new construction jobs that require staircases open on one side. Is it better to construct the closed side skirt board with notches for the treads and risers or to butt all the joints? We would like to use the existing notched stringers installed by the framers. The inside stringer is spaced 1-1/2" from the wall to allow a skirt to fit. The question that arises is how do I set the treads into the notched skirt? Can the skirt be positioned and each tread installed as you go (assuming I have space drive the wedges from underneath)? If I try to preassemble the unit and then put into position, it looks like a temporary brace would be required to support the open side. If the joints are butted, a carpenter told me that a best method to attach the skirt to the treads and risers is to use pocket hole fasteners on the backside. This seems like it would work well, assuming there is access to the underside. Any ideas on how to do this would be appreciated.
(Architectural Woodworking Forum)
From contributor A:
I don't believe let in treads will work in this instance without a lot of unnecessary work. If you want to use let in treads and risers, you need (in the perfect scenario) a clear stairwell opening, and no stringers or other framing to get in the way. You must have access to the bottom side of your stairs in order to drive wedges, glue, and fasten all parts together. There is a way to use let in stringers, but it requires more experience than it sounds like you have.
If I understand you correctly, the staircase is between walls with the stringers already cut out and nailed in place by the framers. The outside stringers are spaced off of the framed wall 1-1/2" by using a 2 x 4 nailed flush with the bottom edge of stringers. This is framed for a build-in-place staircase, which means butt joints. In this instance, I would not attach the skirt directly to the treads. There is too much of a chance for squeaks since the stringers will move as you walk up them but the wall won't.
This is how we install them. Assuming drywall has already been installed, cut and attach skirt boards directly to wall, not to stringers. There is enough room for drywall and your skirt board to fit between the stringer and wall. Next, cut and install risers. Don't attach them to skirts, only the stringers. If stairs will carpet, leave approx. 1/8" space at each end. If they will be visible, back cut your risers slightly and install within 1/32" of skirts, but not touching them to prevent squeaks. Finally, cut and install your treads. Again, don't contact the stringers or you will have squeaks. As each tread is installed, reach behind the next riser and fasten it to the back edge of your tread. Use shims to level as necessary and plenty of construction adhesive at any wood to wood contact points.
This is the simplified version. I left out all the parts about cussing the framers for uneven and out of square stringers. Of course there is more detail to it than this, but this should get you started.
Now for the enclosed staircase - you have two options that I know of, maybe someone else knows of others:
1) Build a pre-fab staircase using let in treads, wedges, and glue as normal. Just before installing in place, use a circular saw and cut all the rise/run triangles off the stringers so they won't interfere with your finished staircase. Slide into place and secure.
2) Build new staircase, just like pre-fab, but build in place one tread and riser at a time. How? Build it parallel with, or out in front of, the framed stringers. This way you have access to bottom side of staircase. Maybe not a lot of room, but at least there is access. Use temporary supports to hold up the top end of your stringers while you assemble parts. After assembled, remove temporary supports, slide into place and secure. It would probably be a good idea to cut the triangles off in this instance also.
In this scenario, ideally you would build it before sheetrock. Temporarily attach one skirt to wall studs. Cut treads and risers to length, allowing for thickness of sheetrock plus 1/8" minimum on each side as well as thickness of other skirt. This way there is additional room on one side to get all pieces in place. When you install it in place, use blocking behind the skirts on each side to center the staircase in the opening.