trim
I love the treads on these stairs which I will be revitalizing. The risers are awful. I was thinking of adding a nose and then using 1/4 be needed plywood to cover the treads. The wall right next to the stairs had an orange peel texture and if I add plywood it will be higher than the wall. The steps change site tionand the rest of the flight has walls in either side and isn't an eyesore. Its just 4 steps that need help.
Any suggestions would be super helpful! Thank you!
There is no reason that you can't make jamb extenders these are routinely used in prehung windows. The casings and whatever you use to bridge the gap to the jamb are just trim and have no structural component.
The trick is to avoid using the exact same thickness. When two pieces are meeting in a plane, it is best to have a slight reveal, an offset (usually between 1/8 and 3/16 inch). This way you have an intended step, not an almost exact match (that is never quite exact).
You can glue the edge of the extender to the edge of the jamb (maintaining the reveal) and pin the face of the extender to the underlying stud.
Most stock prehung doors use jambs that are 4 9/16 inches, wide enough for 2x4 framing (1.5x3.5 actually) and two 1/2 inch drywall faces.
Testor101 is correct in both points. Coping this joint with the coping saw is the way it was most likely done when it was built. It does allow for a corner to be a bit of out of square, but doing this will be taxing on the blade of a coping saw, it is a lot of wood to cut through. But it can be done with patience. Trying to rush through a cut this size will break blades.
If you have access to a band saw, it would make it much easier to do, but to get it a tight fit would still require some tweaking. Whether you run the stock at a slight angle after the cut is started to give the cut an extra relief in the back, what I have been taught is "back cut", so the face of the cut is absolutely tight but the mating faces are gapped slightly, but that does not matter since it is not visible. You could use a rasp to tune the cut too. This back cut can be done with the coping saw too.
Best Answer
There are a lot of ways to handle this based on your taste. The lower 2 treads appear to be cobbled together and if it were me I would tear them out completely taking care to salvage the treads. Then rebuild the lower structure from scratch utilizing the treads. Purely my opinion based on a single photo, but I think it would be easier than trying to clean up what is there and it gives you more options to do what you like. Then, whatever you do for the face of the riser, you can do above the second tread. Even if it sticks out beyond the face of the wall, it will look like a deliberate part of the stairs which will now be treated and seen as their own unit instead of a mishandled attempt to match the wall. At any rate, I wish you well with your project!