So, if they want to give you some of the land, fine. They can legally subdivide their land and give you a piece. You then build your house. The only question is if you want to live there -- presuming you can afford to build a house. This is a side issue, but the land can't be legally subdivided. We can only build because their existing house is so small it can be considered an "accessory apartment", even if it remains a free standing structure. And yes, we can afford to build. We're very close to paying off our existing mortgage on our current house. If they want to stay in the existing house, they can hire the repairs made. They don't seem to care if it's 'remodeled'; they just want to be safe. Well here's the thing. Their current house is just a mess. I don't mean dated, I mean that there's tile falling down in the bathroom (shower/tub is unusable), the roof needs to be replaced, wall board is popping out from moisture in the finished basement, the outside shingles need to be replaced, and too many items great and small to be listed. We live very close by. I've offered to set them up with contractors when we've had work done to our house, I've offered to help them with practical legwork involved in hiring contractors, if there was a hint of financial issues, I'd happily jump in and offer financial assistance. They want the magic person who will read their minds and do it all for free falling into their laps. Now a side of me says, "Forget about it!" and let them let their roof fall in if that's what they really want, but they ARE my parents and I do feel some diffidence about that stance. Exploring the ins and outs of us building seems to be a good time to also explore this issue. I think what we are going to do is talk to a few good builders and get some honest assessments about what is and isn't feasible. I'm thinking (hoping) some estimates about what's involved will either get them on board or allow us to figure we're not living there in their lifetime and move on.

Cost per square foot for remodeling versus building new is always going to be skewed. Reason? To remodel, the existing structure must be disassembled to a point to rebuild. Double labor. New construction is simply building to finish. Single labor. The tipping factor where remodeling is more expensive than rebuilding varies tremendously. If the building requires plumbing/electrical/HVAC reworking plus structural changes, chances are building new will be less expensive. And may be faster. Minor plumbing/electrical/HVAC/structural is always less expensive. In your case, the tipping factor is how much you intend to do. Straightening walls/floors can be a major overhaul, especially when a complete roof is in the plan. Adding bigger windows is a major remodel, and is more expensive than simply replacing windows. Reason? Sheet rock has to be removed, exterior siding has to be removed past the dimensions of the new windows to allow proper framing of the new openings. New window costs, labor to tear out, and labor/materials to replace sheet rock/siding. If the siding cannot be reused(after being removed) new siding has to be bought/installed/primed/painted. Replacing four windows can easily require residing that entire side of the house. Leveling floors will require tearing out the old, repairing/replacing the joists. Same with the walls. Roof may need complete rebuilt to be right. Rip off all the old roofing/sheathing/rafters and rebuild from the top plate of the walls. Could all that be done without all that tearout? Not if it is done right.`

"One of the model homes" In my area, model homes are for tract builders. Tract builders have different economies than single lot builders. There are exceptions to this model but generally it is true. It isn't that teardown, permits etc cost that much (in my area), it is just that you are building on a single lot. There is also the reality that the single lot may have rules that developers don't have that add to cost. As someone who has done both, I will share some costs. We bought a $400k tear down that was 1800 sqft brick 2 story with carport. It cost $12k to teardown and haul away. We had to spend about $5k for some tree removal. The utility hook ups are inexpensive since they are already there - an empty lot is significantly more. Permitting is $3k which is inexpensive - what isn't is that it has taken 6 months and we still don't have permits. Surveys can be $5k - we have to modify lots when we tear down because the rules have changed so much since they were platted. There is water mitigation that can cost $15k for engineering and execution. Developments don't cost much more for the entire development. And then lastly, we expect $180 a sqft for the actual build. Spec houses in our neighborhood are about $1.2M for similar lots, 4500 sqft. We will build a little smaller but that doesn't help on costs that much. This is in Raleigh, an area with (usually) significantly lower costs than NoVa. No one in my area builds a "model home" on a single lot for $300-$400k at 3000 sqft. That being said, there are ways of getting cheaper homes built - ie modular - but that may not be an option depending on the jurisdiction.

That's quite a hike from the sink to the cook top. Also it appears with the current layout that the cooktop is outside the kitchen. I would think through as you are cooking in your current home what steps you go through and how that would work in this design. Most prep work is done near the sink and then taken to the stove. How far are you willing to carry that? Also you often start with taking things out of the fridge and pantry and take it to the sink for prepping. How far are you willing to walk back and forth to get everything you need? If step count and getting exercise is your goal then this might work for you, but I think for everyday use you will find it inefficient. It looks good though.