Believe the solution will be to remove the blanket then either replace with XPS foam then drywall OR frame and insulate/drywall. You’re going to consume up to 4”.

Thank you.

4 inches is so much. We need alot of room to move furniture/patio items up and down

Is there any other way?

@Philbert - your OP mentioned finishing the space. I took that literal.

Measure the door width. Whatever you wish to transport into the basement must fit through the doorway so your stairway need not be any wider. I suspect you wish to insulate against the concrete alongside the stairs. If not then just install paneling, it will be only a quarter-inch thick.

Alternative to furniture in the basement might be shelving in your garage. Here’s how we store ours and still have full use for our cars.

Thank you so much. Yes if we go 4 inches in it will be a few inches shorter than the door. We need to get furniture up and down there. There will be a full bedroom..half bath...living room and office. We do have egress(sliding patio door open to a lower deck) but our upper deck doesn't have stairs so we have to go through the basement stairway for that.

Yes, we must leave some sort of insulation there. I've heard of some sort of paneling over the insulation, but I don't know alot about that.

Our garage is a tight 2 car. I guess we could take the patio furniture out the bottom and through the front door. I want there to be ample room on the staircase though.

@Philbert - attempting to guide you with limited knowledge of your space.

First Question - is your 36” stairwell measured against the insulation batt or to the foundation wall?

Next Question - are you planning to engage a contractor to finish the space or DIY the work?

Our stairwell measures 36” but the door is 30”. Everything in our basement passed thru that doorway. At times I have removed the door itself and the bannister for easier maneuvering.

Insulation consumes space. Typical fiberglass between studs is R13 and 3.5” thick. High density XPS is R4.7 per inch. XPS is better for below grade use because it is impervious to condensation, can be glued onto concrete and drywall can be glued onto the XPS. So 2” of XPS plus drywall would be 2.5” vs 4” of a typical stud wall. Hope that makes sense.

Why not add stairs between the decks if you have basement access? Our garage is 22 feet deep with 10 foot ceiling. The top shelving is 6’ above the floor for clearance to walk under.

Our basement was DIY finished many years ago. Develop a plan and work the plan - same applies even if hiring a professional. We actually placed masking tape on the floor to ”live” the space before building.

Here’s a video of the finished space. No bedroom and the office was initially concepted to be a bathroom.

https://youtu.be/3FqMEqaf0-I

Good luck - hope I’ve helped.

I appreciate the detailed information that you provided. Your basement is so nice! I love your design. Stairwell is measured to the width of the treads, so the actual staircase, not to the foundation or including insulation. I'm not sure how much exact extra space there is because the insulation is there, but it is around 3-4inches of space.

The door width: 30"

Step width (inner): 34 1/4

Staircase width with edge pieces (outer) : 36 1/4

Drywall to Drywall (Upper stair case already finished): 38.5"

We can't add stairs to the outer deck because we live on a pretty steep down slope and it is not level (without doing excavation and a retaining wall). There is not alot of room out there. \

Would foam board insulation work there? Then maybe placing thin paneling or bead board over it to save space?

Let me know what you think. I appreciate your help!

@Philbert - I believe removing the existing batt insulation will provide necessary space for either building a stud wall (approximately 4”) or gluing XPS rigid foam (1” or 2”) then gluing paneling or drywall onto the foam.

How large is your deck? If sufficiently sized a stairway could be built within its confines. For sure I would find means to avoid transporting patio furniture through the house and down basement stairs when direct outside access is available. Photo might help.