First post on here, but been doing a lot of reading!
A few years ago, Hammer1 posted a really impressive reply to someone building stairs. I rarely see that much detail put into a reply before on a forum, and I visit a lot of them for work.
Now I'm renovating my stairs and would be appreciative just a little guidance to see if I'm on the right track, and any helpful observations.
I've attached photos of what is there now, as well as a diagram for what I'd like to do. I spent a couple of hours designing it in Visio, and if anyone would like the original Visio doc to modify for their own plans I'd be happy to share it here.
We found 1 1/2" soft wood treads, 42" wide, and 1/2" particle board risers inserted into a mortised stringer, secured with glued wedges and 3 nails from the outside. 12 of the 13 stairs are open on the side overlooking the hall below. The open side stringer is mitered to accept the riser for a finish corner. There are only two stringers, no center one. The ceiling below is over my basement stairs is finished, I'm probably going to have to remove it to do it properly?
We have 1 1/16" solid maple treads already with nosing on the front and one side. In haste I went out yesterday and had risers cut from 1/2" birch plywood. The plan is to stain and finish the treads to match our hall floor and paint the risers white. Did I goof by not getting the 3/4" for the risers?
My second problem is that the replacement hardwood treads are a half inch thinner in the mortise.
Here's what I'd like to do:
Place 1/2" plywood under the maple tread, from mortise to stringer to give it the thickness of the previous tread. Cover the front of the 1/2" plywood with the riser on the front, using coving (not shown in diagram) under the bullnose of the tread to hide the unfinished plywood edges on the outside of the staircase.
PL Premium on every hidden edge and blocking under each step using 1 1/2" screws to go through the blocking, 1/2" plywood and into the maple tread.
Glue the riser into a shallow mortise on the top of each tread for stability instead of nailing it to the back of the tread.
Cut plugs from left over maple material, sinking two 2 1/2" screws 1/2" deep into each open end tread into the stringer, then fitting and finishing the plugs.
Glue and screw blocks where maple and plywood tread meets mortised stringer.
Will this work?
How does one route/drill for 1 1/16" bullnose? Other than eBay-China I can't find a spade drill bit or router bit of that size anywhere.
What you should have done is cut out parts for the stairway like it was a brand new build before the demo work and tear everything out. That way the amount of time the stairway is shut down is minimal. It's just more work than it's worth to try to tear out some of it and then try to fit parts back in to someone else's work.
The stairs appear to be only about 3' wide. You should be able to get by with just two stringers but what you have there isn't stringers. If you were up around 4' in width then it would need a stringer in the center.
Either the 1 1/16" maple treads or the 1 1/2" treads would work alright. Generally treads are made of a hardwood 1 1/8" thick.
What is it you want to route/drill for the 1 1/16" bullnose. If it's just the side skirt just put the shelf up against it and mark a line. Then cut it with a jig saw.
The 1/2" plywood for the risers would be sufficient if properly fastened.
I've redone a couple of staircases, but I haven't seen anything like what you have there. I'm assuming that the three boards running the length of the staircase are the ceiling supports for the basement stairwell. Those boards should have been part of a stringer arrangement. You do not appear to have actual "stringers".
I know you don't want to hear this, but the correct (or at least more so) repair would be to remove the basement stairwell ceiling, remove the existing routed sideboard, install a new flat sideboard, install THREE new stringers, and then install the risers and treads as you like. I say three stringer because I don't like bouncy steps.
If you are going to try to fit new material into that routed sideboard, well, my hat's off to you. That'll be a toughie no matter how you approach it.