I didn't mean to completely do away w/the curve! It was hard to find the exact photograph. I posted those so you could see some styles of the stairs. All I meant was to lessen it a bit to where you have that landing spot over the side I think this is a waste, too bulky looking, and rather dated. keep the curve, but not like that. Like this. what's wrong w/this one? It's still curved. you don't have that funky ledge either. This fits almost all designs too. also too, it depends on the style of the house, the room, the design. If you have a very classical or traditional home w/classical furnishings, then this would be fine But both of these are rather fussy and on the 'grand' side. Not quite Gone with the Wind, but in that neighborhood. The staircases I posted are little more fitting to a regular home and different styles.

I’m used to seeing birch as a more uniform color, not with all this heartwood and variegation, but it probably is birch after all since it has a quieter grain pattern than hickory. Either way, I would suspect the finish more so than the wood itself. Can you lift a floor register to find out if this is solid or engineered? The narrow planks makes me think solid. If solid, you’ll be able to refinish easily.

Our joists are 2x6, but the span is only 10'-6", so we're ok with 40 psf live load, according to the span tables. What's interesting with the existing floor, however, is that there's a bit of a bow in the floor (like every old house), but it's across the joists, not along them. So it's not a joist sag. We are being conservative with weight, however, We'll not put stone tops on the vanities, I'm using Kerdiboard instead of cement board in the shower, etc. What WAS tricky with 2x6s was the clearance for drains. Not enough for toilet and shower drains. So on the toilet, I traced around the base and made a pedestal of sorts (you can see it in the upper RH corner of the photo above). For the shower, we needed to use self-leveling compound for the base. We put the drain on the low side, and built up the SLC about 1" higher than we would have needed to. Presto: drains with proper slope!

Face frame is oak. The side looks like old growth Douglas fir.