Another fun tid-bit which might make a difference in recommendations is that we have plaster walls... Which makes EVERYTHING we want to do a pain in the a**.

You cannot do as pictured as a door cannot swing over a set of stairs and be ode compliant for safety reasons. I cannot think of a way to do it easily without serious reconstruction unfortunately.

Are you planning to enclose your stairs? You could make it look like a closet, with double narrow french doors at the very bottom, if it were all enclosed.

On our stair case, we put in a pocket door, which slid into an adjacent wall. I can't tell from your pictures if that is a choice. It would be a messy plastery choice.

What about closing it all in up at the top with French doors and using glass around the sides, too?

You can't do it without some major reconstruction which you may not have the budget or space to do. At the very least, you have to wall in the open railing area on the left side of the stair case and add the wider steps at the bottom. I'm also not sure the mid-stairway door is even legally to code.

It would be easier to solve the problems of heat loss, pet containment, and master suite conversion by 1) insulating the attic and upstairs windows to prevent heat loss, 2) putting up a baby gate at the top of the stairs to keep the pets up/down stairs, 3) walling in the part of the attic that you want to use as a master suite.

Why not install Portieres at the top of the stairs? This solution was used in Victorian era when you wanted to keep heat in a room that adjoined another room......can be done in any manner, left open or closed, easily accessible for animals, people and while carrying stuff up or down the stairs, and also muffle sound. There are a ton of pics on Pinterest but I could not figure out how to bring them to Houzz.......sorry, but this is a good picture and they can be one sided or split.....think Scarlett in Gone With the Wind when she told Mammy to make her a dress out of Miss Ellen's Green Velvet Portieres.

Good Book to Know: In With the Old: Classic Decor from A to Z · More Info

You need a 3x3 landing at both the top and bottom of the stairs. If you can create walls beyond that 3x3 space then a door can be put in the wall. Doors cannot swing over stairs.

That last pic is a doozy. Cool design and no code compliance. It's not only the door swing over the treads, there is no continuous graspable handrail either.

I think you'd better take another look at a door at the top of the stairs, please. And whatever you do, I'd design and build with an eye toward reversibility. You're going to want to sell this house someday.

Why not hang heavy, insulated curtains at the top of the stairs?

I'm in the exact same boat! I see your thread is from 3 years ago, what did you do?!

Did either of you come up with a solution? I need to do the same thing at the bottom of my basement stairs.

I have the same problem…how did you end up solving yours 5 years ago ??