I've removed the carpet on the stairs from 1st floor to 2nd floor. There is hardwood under but half the boards are cracked all the way across and deflect noticeable when walked on. I'm debating what all to do to them. I'd like it to be safe, look good and not squeak.

The stairs are 34 inches wide and there is no center support. The house was built in 1954, there aren't stringers, only individual blocking nailed on each side for each stair tread. There doesn't appear to be enough room to put a center stringer in between the ceiling below and the underside of the stairs.

I'm leaning towards replacing at least all the treads, maybe the risers too. Can I stiffen them somehow if I can't get other support under them?

The front few inches of one stairs was not attached, that's the only access to look at take photos that I have.

[![enter image description here](https://i.stack.imgur.com/N8phf.jpg)](https://i.stack.imgur.com/N8phf.jpg)

Thanks!

[![enter image description here](https://i.stack.imgur.com/Z2bI1.jpg)](https://i.stack.imgur.com/Z2bI1.jpg)

[![The only board in the middle looks like a 2x4 on it's side and does not touch the stairs as far as I can tell.](https://i.stack.imgur.com/kkKdf.jpg)](https://i.stack.imgur.com/kkKdf.jpg)