Anthony Flint argues that communities should see the positive aspects of teardown McMansions:

Yes, some embodied energy is wasted in a teardown. But the new homes are universally more energy-efficient, and can be made with recycled materials and other green construction methods. What families want is a little bit more room. A recent survey by the National Association of Homebuilders found that most homeowners want something in the area of 2,500 square feet – close to the average size for single-family homes, which has been creeping up steadily over the decades.Sometimes the extra space is for multigenerational housing, a certain trend in the years ahead. The homebuilder Lennar recently touted homes with granny flats and in-law apartments – the kind of flexible housing New urbanism has been advocating for 20 years or so.

There is surely another trend of “right-sizing” and smaller homes and even micro apartments, for empty nesters and singles. But that’s the thing about the housing markets – one size doesn’t fit all. If some homeowners want more size, they’ll find a way to get it. They key factor in the teardown phenomenon is location.

The same NAHB survey found that while a bigger house was desirable, families didn’t want that house to be isolated out in the far-flung exurbs, miles from anywhere. They want to be able to walk to school or to a park, maybe even to a store to get a half-gallon of milk, or at least not spend quite so much time driving all around to disparate destinations.

And so we come back to teardowns and mansionization. Another way to describe the phenomenon is “infill redevelopment.” Builders are essentially re-using an established parcel in an already developed neighborhood. That’s a far greener step than building a true McMansion out in the cornfields. It’s the essence of smart growth – build in the places already built up, and leave the greenfields of the periphery alone.

One argument for teardowns is the rights of individual property owners to take advantage of a market that will pay them more money. However, this argument tends to pit the interests of the neighborhood or community versus those of the individual. In contrast, this argument is much more community oriented. Flint argues that the alternative is not between an individual and their neighbors but rather between suburban sprawl or infill development. These new large homes may not be ideal and communities could provide guidelines for how big they should be and/or how they should match existing homes and styles yet they are better than new subdivisions.

Flint is hinting at another issue that many suburban communities will face in the coming decades: just how dense should desirable suburban areas become? While teardown arguments seem to mostly be about neighborhoods and retaining a certain kind of character, the bigger issue is whether suburbs should be packing in more houses or even building up. This will be a problem for two kinds of suburbs: those who have little or no open land remaining (and this ranges from inner-ring suburbs to ones 20-30 miles out from big cities who have run out of space in more recent years) and those that could attract lots of new residents. Naperville is a good example as it has a downtown and amenities that would likely attract people and it has reached its limits on the south and west after several decades of rapid growth. Indeed, Naperville has received proposals in the past for high-rise condominiums (and turned them down) and the latest Water Street development proposal suggests expanding the denser downtown.

In the end, these suburbs will have to decide if they want denser development. If they hope to grow in population or develop more mixed-use areas (for example, through transit oriented development around transportation nodes), this might require teardowns and denser development.