In putting together some background materials for a recent meeting, I stumbled upon a 5-year-old report by the Housing Partnership called Filling in the Spaces: Ten Essentials for Successful Urban Infill Housing. Five years is like an eternity in this economy, especially when it comes to housing. But I found the report still really fresh on the principles for dealing with growth in Northwest.
The basic idea is that infill development should be an essential part of the mix when cities are considering how to accommodate growth. Not everyone can or wants to live in high density multifamily neighborhoods (as Clark covered extensively in his post here), but not everyone can or wants to live in single family neighborhoods either. Good infill development—building denser concentrations of new housing within an established residential area —will have to be done well to be politically viable.
What is infill development? The report has a great chart that illustrates where exactly on the spectrum of “units per square acre” infill development fits. 
Click here for full size chart.
In Northwest cities, infill development typically takes the form of townhomes or courtyard housing, both of which I wrote about in a post called Legalize Neighborhood Density. Infill can look a lot like traditional single family housing but it packs more units on a smaller site. There are a lot of examples but in Seattle B9 Architecture’s Urban Canyon project is a good one.
Currently Seattle is revising its low-rise code and is considering the rules developers must follow for this kind of development. A leading local advocate, David Neiman of the Congress of Residential Architecture (CORA), wrote a great piece in the Seattle Times asking “Is Seattle ready for design, density and affordability?” The answer is yes, and CORA has some really great ideas about how to ease the many worries in single family neighborhoods about density, parking and affordability. The idea is to allow developers to get creative with fitting more units into smaller spaces, with shared open space, and creative solutions for parking, and surface water management. If they can sell the resulting product to home buyers and to the surrounding neighborhood, then they should get a permit to build.
Portland has already moved ahead with its work on courtyard housing. Courtyard housing and townhomes provide a much needed option for families who want to live in the city but also want a single family feel to their home and neighborhood. It’s proven difficult to keep these kind of housing units affordable, though the Housing Partnership report’s ten principles are a helpful guide for policy makers on how to balance existing code requirements—which can drive up development costs—with innovative approaches to density. They are worth listing here:
- Build public understanding and acceptance of Growth Management Act obligations
- Make innovation a positive outcome for current residents
- Make innovative housing the preferred choice for builders
- Make infill housing a profitable business
- Help new housing fit well into old neighborhoods
- Identify market demand and plan to meet it
- Design sites for livability and functionality
- Put aside the old stock plans and start over
- Write new development codes that promote good site and home design
- Develop processes that promote rather than penalize innovation and infill.
The suggestions CORA makes follow these principles quite well, especially the last one. City governments and planners need to support infill as a housing option because it supports the basic principles of smart growth, and creates a more affordable option. But cities will have to write land use code that promotes new ideas rather than making those projects more difficult to build. Smart innovation—especially with good design—could win over many skeptical single family neighborhoods that currently resist accommodating more infill development projects.
David Neiman
In the Times article I addressed the issue of affordability & how the density limits in Seattle’s land use code have an inflationary effect on the cost of housing. The math is pretty simple. The amount of building you can put on a given spot is fixed by the code by a standard called FAR (floor to area ratio). So:Lot size * FAR = Building Square FootageSquare footage / number of units = unit sizeCurrently, the number of units is dictated by density limits in the code.Today, in central Seattle, the average townhouse sells for about $300/sf. (post-crash pricing). To produce market housing that is affordable to a family of median income, the average unit size has to come down to about 1000sf. Currently, the average unit size is over 1500sf. This number is not driven by market demand. It is driven by the land use code density limits.CORA NW recently sent in a brief to the city council that illustrates these issues and provides the sales data as well. See http://coranw.blogspot.com/2010/03/density-limits-explained.html
Justus
Since moving back here from the east coast, I’m always surprised by the absence of rowhomes in the pnw. I suspect that true rowhomes would be illegal here – or just impossible – due to parking requirements, but is that the real barrier? I always wonder if it’s just as much cultural. We tend to think of rowhomes as quaint and made of brick,
Justus
but they don’t have to be. http://www.flickr.com/photos/justineandsimon/1436733515/in/set-72157602089936748/They offer significantly better urban design than townhomes, and put more units on an acre (and fewer cars). Has anyone is Seattle given them a try?