We're nearing the end of a major remodel and I need to sort out the interior stairs & steps. I've done a lot of online research but want to ensure I'm on the right track.

First the easy one - a step leading into the kitchen. I need to build a single step up from living room with concrete slab into kitchen with raised foundation (shown in attached pic). The raised foundation is approx 10.25'" high, so I'm planning to split the difference and build the step 5 1/8" high. I'll frame out the rectangle with 2x6 boards ripped down to the correct height and I'll fill the interior with blocking every 12". The top board will have 1/2" overhang on each side and front. What kind of wood should go on top? Also how best to secure the step to the concrete subfloor? Should I screw & glue (using concrete screws & specialty glue) some 2x4s to the floor inside the box, then screw the box to those 2x4s? The whole thing will later be covered by hardwood floor material.

Now the more difficult question - the side of our stairs to 2d floor were fully covered by drywall but I want them to be more decorative and follow the outline of the rise/run (shown in pics attached). I cut out the existing banister and was surprised to find that it wasn't secured to the stairs but rather sat "outside" the stairs. There are stairs, drywall, 2x4's for banisters, then drywall again. I'm having someone build & install the banister for me but he said I need to extend the length of each rise/run into that drywall/2x4/drywall area so then he can attach the new banister there. I have no idea how to do that and it's possible it's beyond my capabilities, but I'm interested in trying. Any suggestions on how this should be done? Basically it requires extending the width of the existing stairs about 6âÂÂ. Our rise/run are non-standard but maybe the best way to proceed is to rip out all existing drywall there, buy a pre-made stringer and then customize and attach as necessary?

Thanks in advance.

Nancy