Hello all! New home owner here! We have a split-level, twinhome from the late 70's with the ever classic stairs with no backing (a la Brady Bunch). Ours have grungy carpet covering them and under that are wooden boards that are beyond restoration. I would like to remove the carpet and replace the wooden steps (not replacing the carpet). How do I do this? What kind of wood do I buy? Is it as straightforward as I think it will be?

 

Can not even tell what your trying to show with those close ups. Back up a little.
What do you want then to look like?
No backing? Guessing you mean no risers.

 

Pretty straight forward. Your treads are undersized to begin with, so putting new ones will be a plus. Look at the box stores for stair tread bull nose. It is about 11" deep, 1"+ thick and comes in varying widths from 3 to 4'. It can be bought in pine or in oak. Either would finish just fine, although I personally would not paint any of them. I'd take the opportunity to repaint the stringers after you remove the treads, so when you install the treads it will be a clean look.

 

Yes, sorry - I did mean stairs with no risers. I don't totally have the vocabulary down yet.

 

I would add that you'll be money/time ahead if you stain and apply 2 coats of poly to the treads before you install them. That way you only have to putty the nail holes, sand lightly, remove the dust and apply the final coat of poly and the stair case is only closed for 1 day while the poly dries!