Exciting project! Lots to think about... Since it's over the garage, do you need to worry about fumes, insulation, fire codes, etc.? Additional soundproofing for when the garage door goes up and down (if anyone uses the door while another person is asleep upstairs)? Also have you looked into height, lot coverage & setback requirements? (Sometimes the setbacks for garages or single stories are different than those for 2 story structures.) Other items which you may already know, but just in case... - Building an adequately stiff floor over the long spans of the garage below without requiring posts below. - Heating and cooling of the new space, since the space below is (probably) not heated or cooled. - Where your plumbing lines / waste drain will run, and will that require tearing out any walls below And others I'm sure the pros will think of.

Thank you so much, Jennifer! I will check it out. Unfortunately, my choices are only SW. I do love the richness of SW Gauntlet Gray! Very nice!

Up vs. out will also depend on your location. We're in California, for instance, in an area where houses like this are pretty ubiquitous. It can be challenging to build up because you need a much more robust foundation in earthquake country. We had it costed when we had to replace part of our foundation a few years ago--actually asked about building out, up, and digging down since our basement is daylit and has 6' ceilings. Up and down were prohibitively expensive. Out was more than we wanted to spend, but at least feasible. We ended up just working within the existing footprint, and maybe someday will build an ADU instead. One challenge we had with a layout similar to yours is that we could not figure out a good place to put a master suite where you wouldn't have to walk through either the kitchen or a bedroom to access it unless we rendered some of the public rooms less usable, and we didn't want to do that. We ended up just adding a bathroom where your planned new bathroom is, with access off the bedroom. Not ideal since we really wanted a third bedroom, but it wasn't worth breaking the flow of the house to do it. We do know people with basically the same layout who went up and used that middle hallway for the stairs, tucking a closet underneath. That works better for the layout (IMO) if you can swing the foundation cost, but where we live it would have been a lot more cost effective to buy a new house. And agreed with @cpartist that this is not the original layout given the age of the house. If it's similar to the houses like this in CA, it may have looked much like ours: living, foyer, dining, kitchen on one wall, bedroom-bath-bedroom on the other, with a hallway in between. Kitchen would have been walled off from the public rooms. Layouts probably varied in other parts of the country, but you could look at nearby homes to see. You might think about how you use those rooms now and if there are ways to reconfigure that space, too.

Great advice. I should have mentioned that the master bedroom is on the second floor and the integrity of the two car garage will remain the same. There is an unfinished room above the garage. Thank you for the tip about heated floors.