I think it is always a good idea to go to your town planning office and speak to someone about what would be required in terms of zoning and permits, and the schedules for obtaining those. Obviously it depends on the town, but our staff is very helpful in this regards. If your house is a typical one for the area they may also know of similar work other people have done which might give you ideas. And for us it was nice that when they saw who our architect was they were familiar with him - we needed a variance and that smoothed the process. Same thing for the contractor - our inspections have occurred without delay (fingers crossed).

It will likely be cheaper and faster to remove the center section and start over. So that said let your architect draw whatever works best on the rear ignoring what is there now.

@3onthetree -- yes, this revised plan (with the addition either off the side or rear) would add a guest bedroom on the main level and expand the current half bath to make a full bath (or 3/4?) for guests or general main level use. We wouldn't make any changes in the basement with a side addition. If we went the rear addition route, would connect the basement portion of the addition to the current walkout basement, but no major changes. I see what you mean regarding the many entrances and outdoor spaces...I just don't know how to remedy this. I HATE the walkout basement garage (that is now just a parking area since the previous owners turned the garage into living space). It makes no sense to me...so you park at this level and then have to haul all your stuff upstairs? And then, if you want to go outside to play, you are going out through a different entrance (on the opposite side of the house) to access the nice part of the yard--where do you keep your shoes?? I find we spend most of our outside time in the side yard and get there through the sliders in the dining room (this is also where we have a nice deck and pergola and the ground is flat and accessible). In the picture below it is the space I colored red. What would make sense to me would be to create a mudroom off that side of the house and then add new parking (not sure where or how) to that side of the lot. But then what do you do with the walkout basement garage parking space (I guess MIL would still park there)? We also have a detached garage behind the house to the left -- but that is used as a workshop (not actual parking). Maybe I'm overthinking this and need to reign it in. Maybe we don't need a guest room and bathroom. Although it would be really nice to improve the flow and function on the main level and how we access our outdoor space. At any rate, thank you for your thoughts.

I am thinking what latifolia said. Mostly because of how expensive Reno’s have gotten especially adding a floor. But it would be great if you could get some more info on the ground that could help you think things through using “ facts”: garage load- bearing issue; maybe looking around in “ the good school” areas a bit with a realtor— not that you’d be buying now, not wringing hands over current interest rates, but what are the existing houses like, in the 3-4 BR floorplans. Then, how close would the “ money not spent” come toward a new ( to you) upsized house? Also, what are the comps in your own neighborhood. And, would you be in a situation to be “ sort of looking” and jump if somcame up? (I generally think that’s hard because “ looking” can be pretty consuming, you have to go see the house, and jumping means quickly analyzing the situation and if it’s actually a good deal, getting right on the offer.) Good schools are important but it’s also not always possible that K-12 are all great in a given assigned zone. Plus I have friends who bought in an expensive big- city suburb based on terrific schools, only to be now facing possibility one of their kids would do better in a private school, plus having a job change that alters the dynamic. Anyway, lots to consider.