It is not good to have a door at the very top of the stairs without a resting landing. I can't see your whole floor plan but I can see that it is not the most efficient design. You have a lot of wasted space. Take another look at your design or hire an architect to help you.

How about a 36" wide set of two french doors with frosted glass. I whole heartedly agree with having a landing at the top of the stairs. Also check code on having a garage below a sleeping or living area, but I think a door at the bottom & top should take care of that, however they may require a fire door.

I cannot see the whole floorplan so I can't comment on efficient use of space. It looks okay to me.

Can you add a turn in the staircase to help with the desired landing as mentioned above? This will have the door not opening directly into the hall (which I would prefer) but create a small foyer/landing just inside, You can place the locker directly across from the door or have a great piece of art, bench, or sofa table there while placing the locker in the hall. It would be best to turn the steps to the left as the living space appears to be on that side of the space so you will enter toward the living area, not the bedroom. Yes, it will add another turn to get into the apartment, but again I would rather the door not open into the hall as it is, also this will add a tab bit more privacy and sound proofing. I like the idea of double doors or french doors at the top. If more space is needed, consider a stackable washer/dryer unit.

I'll sure give it a try. Currently the staircase is designed as a L shape with a pretty generous 4x8 landing between floors (room for a narrow bench and table?)

As much as I would love the idea of a top landing I am just barely able to keep the required clear ceiling height. The area on either side of the apartment is sloped ceiling (6 foot and decreasing) so I can't come up to soon. I've tried to keep the living and kitchen areas as large as possible since that is where we'll be spending our time when we aren't downstairs working on projects. There is one full tread outside the door.. --And I love the french door idea...

Another suggestion is that you don't need a door at the top as long as you have one at the bottom and the stairwell is enclosed.

I like that thought! Thanks much! I was planning on enclosing the stairwell at the bottom and top to help with defining the entrance-transition from shop to living area...and for sound and climate buffer....But perhaps just one solves the issue.

Hobby auto shop + apartment above = several safety and fire regulations you must follow. You must check with your town building department before you do anything. No fumes from below may be able to penetrate into apartment. Firewall separation between the two, and at least a fire-rated door. You may need a second exit from the apartment.

I'll be using 5/8" Type X gypsum on the auto shop ceiling and staircase walls..and a fire rated door. I'm outside any town or county building department's jurisdiction and building with cash. However, I'm planning on having a private plan review prior to construction..and a trusted private inspector.... I've worked for municipalities so I really do value the codes!