Please help. I have a 45 year old staircase where they used thin presswood for risers. A few of the risers are cracked. The treads above them sag when walked on. The treads are 1" solid oak. The connection to the stringers on either side is fine - solid as a rock. But these are 45" stairs, and I'm guessing the middle support (if there ever was one) has either worked loose or is otherwise useless (for at least for a few of the stairs).
So I definitely need new risers and I want new treads (color change and the old ones have nail holes).
A couple of contractors advised me to have the entire staircase completely rebuilt.
A couple of other contractors said I'd be fine just capping the existing stuff with pre-made treads and risers (that the weakness in the old treads would disappear).
It looks like this staircase was built from underneath so I guess those are the only 2 options - I can't see being able to get the existing treads and risers out from above.
I thought that if I inserted 3/4" plywood vertically under the existing treads, against the existing risers, that that would add support and stop the sagging. The nosing of the existing treads projects about 1.25", so there would be room to tuck a plywood riser in there. And THEN cap everything off with new pre-made treads and risers (so the risers would be doubly strong and offer needed support). But EVERY contractor has looked at me like I had 2 heads when I offered that suggestion.
Please help. Just how much support are the risers responsible for? Do I need the entire thing replaced? Do these capping systems work?
I know it's rare to have to deal with cracked risers, but I'm hoping somebody has some ideas. Thanks for your help.

the risers are important as the tread is and as the stringers are..they all work collectively to hold your stairs sold and support weight....the risers need to be nailed into the back of the stair treads..and need at least 21/2" nails 8d-10d for support.

you don't need to take the entire set out, but if you want the set sound and virtually squeak free,you should do the work form behind/underneath..its nothing to cut open a wall and patch it compared to the Frankenstein m you want to create.

not to say it wont work..but it probably wont and will have squeaks..you need to support the ass end of the tread and this is done by fastening to the riser.

Thank you so much for this insight. It makes a lot of sense.
Okay, so we'll remove the drywall underneath the staircase and remove the old risers. Then put new 3/4" oak risers in from underneath. Then we'll cap the old treads with new oak treads. We just noticed that the first riser at the bottom of the staircase will be too "short" once the new floor goes in, so just capping all the treads should keep the height of all the risers more uniform.
Is there anything with this plan that we've overlooked? Thanks so much for your help.

pull the old treads out form underneath too..and then you can slide the new ones right in..

whatever floor is building the height up should or could be removed..

the 3/4 height change on 1 tread will not effect the job..you will adjust naturally to it..

Thanks so much for your suggestion. I hadn't thought of pulling out the treads.
I would have a problem with that though, because the existing stair nose(s) are beveled, not rounded, and it looks like it would take an eternity to try to cut new noses to fit into the existing mortise(s). I can't see being able to get a good tight fit.
But then, that begs another question. If it's a mortised staircase, how can someone replace risers? I can cut the risers to get them out of the mortises, but how would you get new risers into mortises?

open the wall and there your answer lies..=)...slide the old ones down and out..slide the new ones up and in...(keep your mind out of the gutter)

You make it sound so easy.
So I have to take off the drywall underneath, and unscrew the existing risers (yes, I can see each one is screwed to the tread below in 5 places). And remove whatever blocks and wedges I can see. Then open up the wall in order to slide the risers out (and I bet there will be glue trying to stop me at every turn).
Another idea, seeing as I'm open to removing the drywall underneath, but I haven't warmed up to the idea of opening up the side wall yet. Would it be possible to kind of "sister" the existing risers from underneath? Like leave the existing risers in place and just screw some 3/4"(?) wood over them from behind? To act as a reinforcement? Screw the wood to the tread below it, and then from the top, screw down through the existing thread into the wood? (the tread would be capped over anyway, so it wouldn't matter).

are you asking permission?


do what you like,,they are yours..=)..

Does it make any sense? Would it work? Am I out to lunch?

im on the internet..i cant see the job...but didnt you start off saying your risers are cracked which lead u to want to replace them?..

listen....you can do whatever you lie..they are yours...if it works..it works..if it dont..it dont..then you have to do it again..

this is why you should listen to a pro who is there and ca asses and ultimately has to stand behind the work..

if i did this job..i open the wall..rip out risers and treads..install new ones..secure..test..brace if need smore..wedge..shim...screw..glue...whatever it takes..

i can not give you anymore info..im not doing the job..and cannot or will not contest a man on site;)

you understand how stairs work and cant tackle it if you wish..or let a pro handle it..we have spent years acquiring skills..
and its how we make a living... good luck

Please don't misunderstand me - I do thank you for your help, and I appreciate every bit of it. Cracked risers are not something anyone seems to write about on the internet (or seems to experience in general) and I need to know how to proceed.
I've had about 6 contractors in here to assess the situation. The 2 contractors with supposedly the most experience and the best reviews simply want to cap the stairs - no fixing of the risers at all (which scares and surprises me). 2 of the contractors want to rip out the entire staircase and build from scratch. 1 contractor can't make up his mind and gave me quotes for doing the job 2 ways. And 1 contractor mentioned something about going underneath but gave no details. So yes, I'm more than willing to let a professional handle the job, if only I knew who would do the job properly. Which is why I'm searching for answers.
I'll do as much of it as I can. I'll leave the rest to a professional. But I've got to be able to choose a professional who has a logical solution. And to do that, I have to learn more so I'll know who to choose.
Thanks for all your help - I've learned a lot.

i appreciate that and this part of the process ca be difficult..

i cant see your damage so i cant offer a simple solution..you must select on experience, trust and who you like..in that order should yield a good result..

however.. a total stair rebuild is not crazy because that is in essence what you are doing if you take out riser and tread and install new..the only old parts will be the risers..id they want o rip out your stair case and install a totally new one..then in my opinion,this ids not necessary.

Thanks - I appreciate your straight answers. Now that I have a better understanding, I'll go back to some of the contractors and have a more in-depth discussion. I want to do this right. Your advice has been very helpful.