The single-family home is the most important feature of American suburbs. What happens when conditions change and pressures lead to more multifamily housing units and denser housing in suburbia? From California:

In June, as Ms. Coats told me about the house and the neighborhood from the doorstep of her bungalow, she gazed toward a fresh foundation that had entombed the back half of Lot 118 in concrete. Over the next few weeks, a construction crew erected a two-story building that filled in a green rectangle from the Clairemont Villas brochure. A few feet away, the original four-bedroom house was loudly gut-renovated into a pair of apartments.

When the workers head to their next job this month, they will leave what amounts to a triplex rental complex on the type of lot that in the seven decades since Ms. Coats’s family moved in had been reserved for single-family houses. It’s part of a push across California and the nation to encourage density in suburban neighborhoods by allowing people to subdivide single-family houses and build new units in their backyards…

In the vast zone between those poles lie existing single-family neighborhoods like Clairemont, which account for most of the urban landscape yet remain conspicuously untouched. The omission is the product of a political bargain that says sprawl can sprawl and downtowns can rise but single-family neighborhoods are sealed off from growth by the cudgel of zoning rules that dictate what can be built where. The deal is almost never stated so plainly, but it is the foundation of local politics in virtually every U.S. city and cuts to the core of the country’s deepest class and racial conflicts…

“It doesn’t fit.” “It’s adding people.” “We don’t want that here.” “There’s other places for that.” “We just want to keep our neighborhood like it is.” “They want to push us out and tear our houses down.” “Parking.” “Parking.” “Parking.”

Several quick thoughts on these changes in many suburban communities:

1. Where exactly this density will happen will be fascinating to watch. Will it happen in wealthier suburban communities or will they be able to keep it at bay? Inner-ring suburbs are often already more familiar with such density but this is less common in suburbs further from the big city.
2. The housing pressure is acute in California but is not so clear or as well publicized in many other locations. If this works in California, where else does it show up?
3. The NIMBY concerns cited above will be vocally shared again and again. The appeal for many single-family home owners is the space between neighbors, relatively lots of room for parking, and not feeling like the neighborhood is crowded.
4. How much are #1-3 above linked to another long-term pattern in suburbia: race and exclusion? Homeowners will say it is about protecting their properties – particularly their property values, which single-family home zoning is intended to do – but it is also about who is able to live in the neighborhood and community.
5. The addition of units and people to existing single-family home neighborhoods is a different approach to denser suburbia than creating larger-scale “surban” projects that some would find desirable near suburban downtowns or in large-scale redevelopment.