Very early in the process, before we had even submitted an offer, I visited the Concord building department to ask some questions about the existing septic system. I remember, while I was there, the helpful clerk offered to calculate for me the maximum size house I would be allowed to build on the lot. I suspect she wanted to make sure that there would be no surprises when we designed the house.
Well, she looked up the zoning details and the plot plan and did some calculations. Then she proudly announced that the maximum size house we would be allowed to build would be 17,581 square feet. Well, that added yet one more constraint to our design process.
One of the most common questions I get asked by people when I tell them we are building a house is how big a house are we building. The problem is that there is only one real answer, and that is “it depends”.
The way I think of the house is that we are planning on aging in place and living on one floor. The main floor is around 2,500 square feet, which is generous but not ridiculously large for two people. But we also have a smaller second floor for guests and possibly live in help when we get older. The second floor is around 1,400 square feet. Those are the two numbers that are probably what people think of when they ask.
But that does not tell the full story. We also have an unfinished basement, which will be conditioned space. The basement is, as you would expect, also around 2,500 square feet. And then there is the garage. The main garage is just under 600 square feet, but we are adding a garage extension (“shed”) for another 120 square feet. Since the garage is also conditioned space, that means that we are heating and cooling a total of just over 6,000 square feet (which is now starting to sound like some type of mansion). Then there is a deck and a porch totaling around 820 square feet, but those tend not to get added into the total.
So if you ask how big a house are we building. The answer is it depends. Probably a little too big, but still keeping it comfortably under the 17,581 maximum allowed by the town. (By the way, given the restrictions due to setback and wetlands and height limits, it would probably be impossible to get anywhere close to the maximum. The reason that the maximum is so large is because the town counts the one acre of wetlands in the lot size, and the maximum is only based on the lot size.)
I should also point out that the septic system also establishes limits on the house size, not on the square footage, but on the number of rooms and bedrooms. Our septic system limits us to 3 bedrooms and a 6 other rooms (as defined by the law). As it happens, the house we are building has 3 bedrooms and 5 other rooms (living room, dining room, kitchen, game room, and the second floor family room ).