What are you going to do with the existing spaces? Do you need both bedrooms on the main floor, including the master suite? Is main floor office required? What are the setback and height reqirements/limitations on your lot, and how would a second floor work within those? That would certainly have an impact on where stairs could go.

We are hoping to keep the main floor as close to as is as possible. Would a staircase take up the entire office or would there still be some room left for maybe expanding the laundry room. I wanted to keep that bedroom, but honestly hadn't considered the staircase there. The height limitation is 35 ft, so not too worried about it right now. We can not expand the house on the sides, but can extend front (garage side) or back if necessary, though would prefer not to.

What about on along the DR wall (kitchen-side)?

There are approximately 379 different locations for the stair in the the layout provides based upon the information provided. Do not put the architect in the uncomfortable position of having to politely tell you you are going about this the wrong way. Hire a local competent architect and they will properly address your concerns.

I love how people assume that buying a different house is going to solve the needs of every family. Sometimes, you have to work with what you have. We are trying to make a multi-generational home, there aren't others in our area appropriate for that. If you aren't able to actually help with the question, then no comment is necessary. We are working with an architect and a designer, but sometimes its helpful to have people that haven't been working in this area for 20 years to take a look and have a unique point of view.

"We are working with an architect and a designer"

What does the designer do?

Your questions and concerns are why you hire an architect. If the architect is not addressing your concerns and answering your questions, you need a different local architect.

Good luck with your project.

It's ok to toss around ideas. Your architect could become focused entirely (or shoehorned into limitations) on a singular problem you present to them (e.g. not enough bedrooms), for whatever reason. As a stranger on the internet, I don't have those potential handcuffs and might spark you to think about things prior to diving deep with your architect.

From the drawing presented, I am not sure if the first floor remodel is proposed yet to be built or was built a long time ago. But the Family Room is very tiny, about 12'x13' which includes circulation to the patio. The Dining (that has a fireplace) is very open feeling to a large footprint of the Entry contrary to the Living, and the Entry view is to an uninspiring back wall of the Kitchen. The Powder is exposed. The apparent kosher Kitchen is not very efficient, and a bit wasteful when compared to the size of Family and Breakfast. Not a lot of overall storage.

So why do I bring those up, seemingly focused on negative aspects? Because maybe the addition should look at the house holistically and also become a remodel better suited to a multi-generational residence:

- Stair maybe helping fixing some of that, say where the Entry closets are or along the Pantry/MasterClosetJr.

- If the addition has 5 bedrooms and no upstairs gathering space, then the first floor Family Room becomes more inadequate. Ridding both kitchen peninsulas and moving the island back makes the Family larger.

- Laundry is in the circulation pass-through and might become inadequate with 7-8 bedrooms.

- More people need more storage, though realistically the cars park outside and the garage probably becomes storage.

Thank you 3onthetree, while I agree on most of your concerns about the lower level, it was remodeled about 8 years ago and isn't going to be changing right now. Whlie I saw the plans as they were being created, I was in the position of 'smile and nod', not really give input. I'm hoping to add a bonus room/family room upstairs for a better 'movie night' gathering area, but really am unsure how much is actually going to fit up there. I'm also trying to figure out attic storage for all our stuff (like luggage, sleeping bags, etc) We definitely use our space differently than my parents do, but first I need to figure out what we actually have room to add when we can't change much that is already in place. Entry closet seems the best location right now for the stairs, though not sure about which shape. One drawing that was presented to us cuts off the hallway from the master bedroom to the garage and I'm not sure that fully works for us either.

This is an interesting problem given that the OP has stated that she wants to minimize changes to the existing first floor. I think the best possibility is to locate the stair where the closets are near the entry and dining room. A switchback stair opposite the powder room would work and most likely not require removing load bearing walls. It could be open and a dramatic feature visible from the main living areas. It would also be about midway between the front and back walls, making the layout of the upstairs rooms a little easier.

Does the floor plan posted represent the house as it exists currently?

Yes, this is the floor plan after the remodel was done 8 years ago.