Attached Shed Conversion To A Bedroom Closet

[Jerel Davis]

I bought a 3/1 1250 sqf home and there's an attached shed with finished roofing right beside the guest room and you can see how the framing is attached to the home. It's on a concrete slab. It's about 100 sqf.  The goal is to convert the attached shed into a small walk-in closet for the guest room it's attached too and the other 50 sqf as a utility closet for the washer, dryer, and water heater.  The water heater is already in there.  The framing is flat on the slab.  I think I have to cut a wall in the guest room for the door frame, construct floor joists for the flooring in the closet, put up a wall to divide the closet from the utility closet, and finish the walls in the closet.

The reason I'm doing this is because the guest room is small (12x11) and has no closet and the appliances are being relocated to the attached shed to convert the laundry room into a full-bath connected to the guest room (laundry room is 9x7.25).  It'll make the house a 3/2 1300 or 1350 sqf home.

What generally overlooked costs are there for this conversion?  Should I consult with a contractor?  What concerns would you have about this besides the appraisal?  Can you think of a cheaper way to build a 3/2 while relocating the appliances and still having a closet in the guest bedroom?

Bathroom: +$4000 (appraisal report) +$??? (Market) SQF: +$35 (appraisal report) +$100 (Market)

C+/B- Neighborhood rural