Seattle's Stacked Flats. Almost Perfect...

Seattle is still way behind on our state-mandated deadline for delivering our “comprehensive plan,” which is our 20-year plan for housing growth. While Seattle’s Planning Commission and its internal staff pushed for a future where housing is no longer a scarce commodity, Seattle’s outgoing Mayor Bruce Harrell overruled them with his plan to increase scarcity, exclusivity, and unfaffordability. 

And, although no one would accuse the 2024-2025 Seattle City Council of being ambitious or particularly forward-thinking, even they weren’t ready to sign up for something quite so embarrassingly tepid as Harrell’s plan.

And with some cajoling from advocates, they made some surprisingly big amendments that mean we may soon see stacked flats in a our neighborhoods!

Remember that stacked flats share stairs, meaning much more of the building gets used for actual living space than in townhomes, where each home has its own stairs. And you can stack the homes, meaning you can get more housing units onto a piece of property without covering up all the land and cutting down all the trees. Since they share walls, they are much more energy efficient. There are also fire-related safety rules in the code that limit how far a flat’s front door can be from the shared stairwell. This ends up reducing the number of units per floor, encouraging more family-sized homes. Since each home is only one floor, stacked flats are also much more friendly for people with mobility challenges. 

In short, stacked flats get us more, family-friendlier, and accessible homes and leave open more greenspace. 

And through miraculous work done by the Complete Communities Coalition, we’ve wrangled the council to produce the best stacked flat legislation in the country. It feels SO good to start leading again as a city!

Still - unfortunately, because of high comparative market demand for townhomes, I think more work will be needed to make this housing type truly viable at scale. After we get through the remaining elements of our comprehensive plan update (corridors, neighborhood centers, etc.) - I do think we should come back to this and go from the current “very good” state to “truly great.”

We cannot do it now, because that would trigger a new environmental impact statement process. If we make our planning office do that now, they won’t get the other stuff out the door. (Also, the state should get rid of this burdensome and unhelpful process for infill housing in urban areas, as California recently did).

So even though it’s going to be a while, I want to get down my suggestions to make this highly efficient, family-and-senior-friendly housing type widely available and more likely: 

(If you don’t know terms like “FAR” and setbacks, see my handy little appendix below)

I would break the changes into two phases:

Phase I: Things The Council Can Do Right After The Rest of the Comprehensive Plan is Done

(I’ll use a standard 5000 square foot Seattle property to illustrate)

1. Increase the baseline stacked-flat bonus so that all stacked flats are allowed to build at a 2.0 FAR (10,000 square feet) instead of 1.8 FAR (9,000 square feet), keeping the current 50% lot-coverage and four-story limit.
   

2. Increase the tree-retention bonus from .2 FAR (1000 extra square feet) to .4 FAR (2000 extra square feet), and pair it with the current 10% increase in lot coverage allowed. Such buildings will be allowed 60% lot coverage and 2.4 FAR (12,000 square feet) of building space.
   

3. Offer the same bonus for affordable housing, or social housing, as offered for tree retention. 

4. Eliminate all setback requirements for stacked flats, which will make it much easier to preserve trees, since they have this habit of growing in random places all over a piece of property. Another way of saying this is that the flexibility provided by removing setbacks means buildings can be built in all kinds of different spots on a piece of property. Thus more properties will end up having trees that don’t need to be cut down. This also means more local builders will be able to get the tree bonus and we’ll get more stacked flats. 

5. Set building heights so each floor can have up to 10-foot ceilings. This will increase light and livability.

6. Allow an extra few feet of height for sloped roofs. This will increase visual variety, which will make it a little easier for neighborhoods to adapt to stacked flats. Since it’s not a requirement, it won’t force unnecessary costs on anyone either.
   

7. While “transit-oriented development” or “TOD” is currently considered a separate topic, the stacked-flat framework can serve as a conceptual baseline for TOD that is not in a more intensive urban center. Sites within a five-minute walk of frequent transit (15-minute peak frequency or better on buses) that aren’t already more intensively zoned, should build on the above framework. TOD should allow 6 floors and 50% lot coverage as the baseline (3.0 FAR, or 15,000 square feet), or apply a bonus that reaches 60% coverage (3.6 FAR, 18,000 square feet) for tree preservation, subsidized affordable housing, or social housing. 

8. Launch “family-oriented development.” For properties within a five minute walk from a school or 1-acre+ park, allow the same height, lot coverage and FARs as outlined for transit-oriented development. However, for these homes, require that at least 25% of the building be dedicated to homes of 1000+ square feet, with 3+ bedrooms, and that at least 75% of the building be dedicated to 850+ square foot homes with 2+ bedrooms.
   

9. Where a property is both 5 minutes from frequent transit and five minutes from a school or qualifying park, the family-oriented framework should govern.

10. Last year the state legislature finally passed a modest condo-liability reform bill for 6-plexes and smaller. Add condo-liability reform for all buildings sizes to Seattle’s legislative priorities for Olympia, and fight extremely hard to get at least buildings up to six stories and smaller covered by condo reform. 

11. Formally ask Mayor Wilson to study and make recommendations on a series of code, fee, and financing changes in Phase II.

Phase II: follow up after a bit more study

After the Office of Planning and Community Development studies the viability of these approaches, we should see something like the following (I’m not sure these are the exact right decisions; they are meant to be directional):

1. Cut utility hookup fees substantially (perhaps 50% or more) for stacked-flat buildings. Consider paying for this by raising utility hookup fees for building types that are spatially inefficient, like townhomes and McMansions.
   

2. Clarify the degree to which Seattle’s building codes can diverge from state building codes. (We do this with single-stair buildings already.) Explore opportunities to:
   

   1. Reform elevator requirements (to remain in line with the Americans With Disabilities Act), reducing onerous additional size requirements that increase costs and prevent elevators from ever getting installed in smaller buildings.
      

   2. Remove the most onerous water-management-related requirements for stacked flats, since they promote less runoff by covering less of our open space than townhomes. 
      

   3. Adopt European code standards for windows, which will increase flexibility, reduce costs, and maintain energy efficiency standards.
      

   4. To the degree possible, increase the threshold for switching from the residential to the commercial code. And use a building-size threshold (instead of unit count) that is big enough to cover Seattle’s stacked-flat buildings.
      

      1. If the above does not prove possible, create a “mezzanine” code that merely requires stacked-flat buildings to incorporate commercial code fire-suppression techniques while otherwise retaining the residential code.

3. Issue a bond that creates a rotating fund for aiding the financing of stacked flats in high-opportunity, low-displacement neighborhoods. (Stay tuned for an article in the near future on innovative public financing arrangements to stimulate housing growth.)
   

4. Consider MFTE tax abatement for stacked flats that meet certain target requirements, like high-opportunity, low-displacement neighborhoods, perhaps near schools and with family-sized units.
   

5. Review the family-oriented development requirements above to ensure that the percentage of building that is required to be set aside for families aligns with local families’ demand for housing. If there are too few customers to make such buildings viable, reduce the percentages that must be set aside for larger homes, but continue to require that at least some significant portion remain reserved for larger homes. 

I believe this will not only set us up for much more housing in general, but also much better housing in terms of how much space it takes up, and how nice it is to live in. 

In the coming months, I will have much more to say about the council’s next steps–a richer discussion of transit-oriented development, what to do about daycares and parking, how many “neighborhood centers” should be legalized (and where they should go), how to reduce longer-distance travel trips, especially by car, what to do with higher-rise and very intensively transit-served areas, how to increase tree canopy, make streets safer, and how to handle controversies about Seattle’s MHA (inclusionary zoning) program. 

Appendix of relevant terms:

• FAR,” or floor/area ratio, is a way of regulating the square footage of a building. A FAR of 1.0 means you can build 5000 square feet on a 5000 square foot lot. 2.0 means you can build 10,000 square feet, and so on.
  

• Lot coverage limits say how much of a lot a building can cover. A lot-coverage limit of 50% means only 50% of the lot can be covered.
  

• Height limits are usually discussed in terms of the number of floors allowed, though the rules also put actual limits on the distance between the ground and the roof in feet.
  

• Setbacks are rules that say how far a building’s edge can be from the edge of the lot. We often have rules about these for the front, side, and back of a property, as well as something else called “upper-level setbacks” which means upper floors have to be set back compared to lower floors. 

A Note

An earlier version of this article suggested that the changes above be made sooner, but now that I have been made aware that the next stages of the plan are ready for council, I have amended my timeline. I have also softened the tone, in the realization that this truly is the best such legislation in the country at this time. I see a better horizon, but am happy to celebrate our success too.