James, thanks for your reply. We were wondering about the chimney too. It vents the dining room fireplace and the hot water heater. We installed a 90% efficient furnace when we moved in, so that vents out the side wall of the basement, not out the chimney. I'm expecting that the architect will have to incorporate the chimney in the design and we may have to have it built higher to meet code. Yes, that's a gambrel roof on the far side. This house has a nice mishmash of architectural features. No one has ever really touched the original design which makes us cautious and nervous -- the original condition was one of the main attractions to us when we first saw the house. Our architect is an old house owner herself, so that should be a good sign. We are hoping to step the addition in on the left side (looking from the back) by at least a foot. My husband was trying to sketch a possible roof line that would join a smaller hip into the existing hip. His sketch looked pretty good. I was just hoping to see where someone had done something similar. I'm not sure yet what the architect envisions. I guess I need to be patient and let her do her thing. : ) Here's a picture of the side with the gambrel:

I'd largely agree w/ Virgil on doing a gable. That said, the house we're building has gables on the roof but a hip on the porch (photo about halfway down this page: http://bamasotan.us/2018/08/heat-tube-and-other-stuff/) due to the very shallow pitch on the porch roof. If you do a gable then put a window in the gable rather than screen to avoid rain coming in. You should also do something between the gable and the screen area to keep rain from flowing down the gable and soaking the screen.

Virgil: We have not signed a contract yet as we just asked for a bid on a plan was drawn but have since decided to not even use that plan since it was more than 150k over our budget. The first plan we had completed by a draftsman was originally done by an architect, however the cost for us to have an architect draw up plans was more than 15k and our budget just simply does not allow for that since we are getting a construction loan and will need money down which to get the loan, we need a plan so its a chicken and egg type situation. The lot is sloped so there will be a walk out basement in the rear and the garage will need to be angled ~45 degrees off the front of the house. I have previously checked out the dwell site and really enjoyed it!! I'm open to any roofline other than straight across at this point as long as it can be built!

I can understand the desire for more light in the house. But are you sure you want to remove all of your southern shade? It does not look like you have much for trees to allow some shade relief to that side of the house when summer is high. Do you like sitting on the porch and using the ceiling fans when it's nice out? If you do, you will need to consider having the other side of the porch wired and installed with fans to make up for the removal on the south side. Other things to consider are going to be reworking the top gutters and drainage without the lower roof to help with that. And the drainage through the exposed deck and below without a roof above it anymore- and snow load in the winter. I can say from personal experience as someone living very close on the lake for many years... and having a full south window in the kitchen and an enclosed porch that is south and east attached. I love my trees and it would be much hotter on those faces without the shade relief. I don't have anything outside blocking the south face of sun in the kitchen. And I find I regularly need to have the blinds down during the summer because the sun kicks in hard. It is very nice to have that much light in the house and extra nice in the winter and into seed starting season. If I had that roof like you do, I would not remove it. Maybe pop in more skylight action to the porch roof, and sure, expand that west window. I'm not sure where you are in MI, you must be really far north to only be able to use your porch for 6 months of the year. I'm pretty far south and we can use our enclosed porch year round, and the unroofed porch pretty much from early spring through early winter. I garden year round off that porch so it's kept usable all year, but snow happens, lol. If you do some cold season fixins to your porch, you could extend your usable season by a bit.