Framing and Sub-Flooring - Adding partition wall to garage... need help

I want to add a partition wall to my garage, about two-thirds of the way back. It will seperate the garage from the stairs that lead to the basement. The reason for this would be to essentially create a hallway from my kitchen to the basement. This would be better than leaving the kitchen to entire the garage, and then go down to the basement. It now feels like I leave the house to enter the basement. With the partition wall, it will be a more natural pass-through.

My question is this; Would this partition wall have to be built as an exterior wall? What would the requirements of this wall be? Or could I just frame a partition wall with drywall on both sides?

Thank you very much in advance for any help. I would include a drawing but I couldn't get it to upload.

Welcome to the forums! I don't know anything about your local codes, but most likely you will have to use 5/8" fire resistant sheetrock for the covering, and the door from this hallway to the garage will have to be considered a fire resistant door and be self closing. You will have to deal with lighting and switching as well as additional receptacles on the newly formed wall (every 12' on any wall over 2' in length).

If the garage floor is cement, you will want to use a gasket under the plate and you will want to use treated lumber for the plate and anything else that might be exposed to moisture and tap con the plate down to the floor.

I mostly just worry about carbon monoxide from running vehicles inside of the garage - getting into the house.

The same with the firecode drywall. Its a good idea because you never know when you could have a fire out in a garage when you have power equipment stored in the garage and a hot catalytic converter underneath your automobile.

There was a woman that owned a 1985 Chevrolet Blazer, full size that owned a dairy farm and bulls that she kept for breeding.
Her husband died and she was left to fend for herself. She didn't know much about automobiles and she ran that truck until one day she brought it into the garage and the cat was plugged up and glowing like a 500 watt flood light.

It caught something in the garage on fire along with the truck and it burned down the whole house. She ended up having to sell all the cattle and the barn and the silo to pay for a new house and a used vehicle.

The fire company was only about 2 or 3 miles down the road and they were a volunteer fire company and by the time they got there it was a total loss.

I would think that if she had a finished garage under her house with firecode drywall on the walls and ceilings - she would still be living there today. It's pretty cheap insurance.