Hi weedyacres--
I enjoyed your kitchen reno and now am watching this with interest. I don't have a solution for your roof pitch problem but what you are doing to the back of your house is exactly where I started in planning a reno to the front of mine. One thing I notice is that the only access (unless there is side access) to the back yard is through the sunroom. If you ever plan to grill or entertain in the back yard, might you want easy access from the kitchen through the nook and out? I can imagine carrying everything (raw meat, dishes, utensils, etc) from the kitchen all the way through the sunroom and back again. I wish I could scan my plans, but I will try to explain. My nook will be about 8' deep but about 12' wide with a shared wall with what is your sunroom ( my new living room) which will be 16' deep. Then I put french doors in the nook for access (these will also be my new front door leading in from a porch or deck). I too originally had a wall that faced the staircase as you do in your plans, but thought the "bowling alley" that was created would end up as "weird space" I can't tell from your drawing how wide that is but it looks about 4'? It would be shaded by buildings on both sides and I was afraid nothing would grow.

Also--my present only eating area in the house is a 9 foot wide by 10 foot deep space, and it is seems really tight whenever I have my parents over for a meal. (I'm single). Not much space for a decent size table.--just a thought.

As for the roof line over the sunroom, a pair of square windows flanking the chimney might look kinda cool, and as long as you have egress windows elsewhere in the bedroom, you should be okay. I just gave up a window in a a smaller bedroom for the roofline of a new mudroom added to the back of my house, and, at first it was kind of weird, but the mudroom definitely makes up for the lack of a window and I don't even notice it much any more. (I still have to paint the new drywall.) and not expensive to get rid of the window. As you would be replacing existing windows (the openings are all ready there) with slightly smaller windows, I can't imagine it would be much more.

Best of luck on this project.
Holly

How about bringing the breakfast nook out the same depth as the sunroom and running the roofline right across, angle the left side same as the right side. Maybe shift the sunroom to the right and eliminate the gap between the sunroom and breakfast nook. Put in a false ceiling at the desired height. Upstairs you could put in a couple of atrium windows to allow light to the upstairs windows. above the false ceiling would be attic space. I would put double french doors between the sunroom and breakfast nook then you could use both rooms when you have a large family gathering etc.
Perhaps you could use those doors as the entrance to the sunroom and eliminate the doors next to the fireplace.
I don't know what that would do to your construction costs, but you are eliminating two walls and the single roof has to be easier than two. I wouldn't be comfortable with the 1/12 pitched roof.

I wouldn't be thrilled about a 1/12 pitch, either. My neighbor has a back room like that, here in Ohio. It's a perennial source of trouble. Melting snow drains very slowly and refreezes on the overhangs, creating a damn that keeps water pooled over the heated space. A well-insulated ceiling and a rubber roof would probably let you get away with it, but gravity is more reliable than the best membranes available.

Not to push you in one direction or another, but your concern about the expense of shrinking the two windows above to accommodate a steeper pitch is almost certainly unfounded. Making the windows wider would be a little more of a to-do, but shrinking them vertically is no big deal. In the context of a project that has you adding to the foundation and expanding the footprint of the house, the cost of shrinking those windows will be almost imperceptible.

Thanks again for all your advice. I'm off to the architect to ask for a steeper roof and connected rooms. You guys are great!

If installed properly an EPDM roof should be fine with no problems. I'd go that route so that you don't disrupt other portions of the house.

Would you have any use for a deck above that sunroom? That might be one way to take advantage of the "flat" roof. You could put doors where the top windows are and add a nice railing. You could even have stairs from outside the sunroom. I don't know where your located, but it's pretty popular here in Phoenix.