Pictures and layout would help or contact a local Architect, sit down with him, tell him your needs and wants and he will design it for you.

Good luck

Space is 25 x40.

Robin,

You have to post a sketch of the layout, mark window and door locations, a few pictures would be helpful for someone to give you a few ideas.

This sounds like a fun project! What are you trying to accomplish with the living quarters though? You mention bedrooms, so are you thinking this is long term housing - as in this will be someone's primary residence for multiple months/years? Or are you thinking that b/c this is a maker space, people might crash there a night or two. This will make a big difference in what you can accomplish with the space.

Are you wanting a kitchenette situation?
Will you have electrical and plumbing in the space and if so, to what extent (main floor only, single corner, all 3 levels, etc.).

What half is the 3rd floor? Is it 25x20, in the middle or on one end of the foot print? Or is it 10x40, running along one side? Is the 3rd floor ceiling gabled or flat? How much of the space, on the 3rd floor, can you actually use?

Like GN mentioned, a sketch or some blue print type of visual would really help. Even if you just map it out in excel, that would be helpful and would show scale.

Agree with ppf. Your first step should be to visit the local planning office to see if the idea is permitted within the zoning that your property is situated. In my area (Vancouver, BC) each municipality has different rules regarding Lane Houses and secondary suites. Regardless of your location, these regulations can be complicated so, once you determine if the municipality will allow what you propose, you should interview Architects who have experience with Lane Houses in your area. Find one you like who you think you can enjoy working with and who has an aesthetic that matches your own. An Architect will be able to walk you through the process and identify any potential pitfalls.

See city hall and zoning offices first. Be sure to ask about how you can provide parking for all these people and their guests, too.

We have already talked to city and working through that We are dividing the property off to be a flag lot so that is not an issue. We are thinking "semi long term housing." Our area is rapidly becoming too expensive for young folks to stay and live and to their art/education. We want to create a semi "dorm" shared household where folks have their own private space and then shared common areas.

Basement is half underground on west side and open on three sides
Second floor has a grade level exit that I imagine will open until a patio/ deck area
third floor could be divided into two bedrooms, windows at end.

thinking we would add sliding glass doors to future decks for all bedroom areas.
Wanting a loft/industrial/steampunk look

Attached is a very rough sketch of the space. We feel doors and windows are movable at this point. Currently base level of electric is in the space, with nice grade plywood walls and antique oak floors. Existing windows are jeldwyn, but do not meet Bedroom Requirements. Single wood stove in center of space is only heat source to date.

Thanks for all the ideas! I know I can take it to an architect, but love the design challenge myself. One idea I have is creating a space that gives a lot of privacy to individual rooms with bathroom centrally located to all. Stairs to loft will split that area into two basically equal spaces. Basement could have 1 bedroom also, but for now think of it as entry way, utility, storage and maker space.

The lot is well hidden in the woods and the structure is very sound. Tin roof, t-11 siding. simple, but ready to turn into something very cool

here is the floor layout