CAST’s co-founder Matt Hutchins, AIA, CPHD, and Seattle Planning Commissioner talks about the major update to the Seattle’s Comprehensive Plan.
one seattle for all - 2025/02/08 10:37 PST – Recording

Seattle is growing (and that’s good)!

How do we make room for new housing and be the kind of city we want to live in?

Seattle’s Comprehensive Plan major update – a 20-year growth strategy.

-        Must include affordable housing and middle housing

-        Housing planning aligns with planning for transportation, utilities, climate and the environment, capital
facilities and parks/open space

Two kinds of affordable housing:
1. Subsidized and deeply affordable
2. Less expensive housing by size, type, and age (ie. ADUs, small apartments

-        Neighborhood centers can hold both types of affordable housing

-        Middle housing is less expensive and a great option

-        Urban Neighborhood housing types: single-family housing with ADU, duplexes, townhomes, stackedflats

We need more affordable housing – where does it go?

-        Neighborhood centers can support both types of affordable housing

Let your city council member know you support affordable housing, and you also support neighborhood centers and middle housing.
oneseattleforall.org

Matt Hutchins addresses the critical issue of “missing middle” housing in the U.S., exploring the housing gap that falls between single-family homes and high-density apartments. Serving as a jury member for the Denver Single-Stair Housing Challenge organized by Buildner, he focuses on innovative solutions to promote accessible, medium-density housing options.

Watch on YouTube: https://www.youtube.com/watch?v=orW8tnmPSv0

Missing-middle housing is a housing type that fits in the middle between single-family detached houses and larger apartment buildings. That’s duplexes, tri-plexes, four-plexes, ten-plexes, and small apartment buildings. It’s any sort of increment of density that is greater than a single-family house, but isn’t the blocks of apartment buildings that is much of what we see in the development world today. Missing-middle housing is important for urban development because American cities have lots of space. They are nowhere near full. We have empty parking lots. We have lots that were never developed. We have space in our cities we can use or reuse. There are many opportunities within our cities to densify and make use of existing infrastructure without having to assemble a whole block or use more “high-wire acts” with regard to development.

• Make good use of small lots

• Use of single-stair buildings is a critical tactic for taking advantage of small urban lots

• Adapt building regulations and make required changes

• Use underutilized urban land

• Use space correctly

• We have already invested in the urban infrastructure

• We can have a more efficient city and residents with a lower carbon footprint

• ADUs and DADUs are powerful tools to keep communities together, keep the property in family, and create generational wealth

• Missing-middle housing is compact, efficient, and sustainable

RiversMeet, a mixed-use project in the town of Winthrop in Washington’s Methow Valley, is positioned to become the upvalley entrance to “old downtown.” The site is a challenging set of narrow parcels overlooking the confluence of the Methow and Chewuch Rivers.

RiversMeet is envisioned as a template for how buildings can work within Winthrop's westernization code while striving for high levels of sustainability and providing more inclusive housing options.

The program will provide two 2-bedroom residential units overlooking the river, with approximately 1,870 SF of pedestrian-level retail space. The second floor incorporates 1,870 SF of office space. The second floor incorporates 1,870 SF of office space, continuing the client’s tradition of renting below market rate to community non-profit businesses.

GREEN DESIGN
1. Concrete mix uses fly ash, reducing use of higher-carbon cement
2. Low-Carbon Foamed Glass Aggregate replaces typical underslab foam board insulation
3. Gutex wood fiber exterior board insulation
4. Low-Carbon Wildfire Resistance Strategy:
- Wood siding treated with a non-toxic solution that provides fire resistance without the high carbon penalty of fiber cement
- Exterior sprinkler system
- Fiber cement siding reduced to areas where it's most effective
5. FSC-certified wood framing package
6. High-efficiency all-electric heat pump space heating
7. High-efficiency heat pump water heating
8. Solar array

TEAM
Client: Peter Goldman and Martha Kongsgaard
Architect: CAST architecture
Builder: North Star Construction Company  www.Northstarbuilds.Com
Civil & Structural: DCG, now Facet   www.dcgengr.com  
Electrical: TFWB   tf-wb.com
Environmental:  Grette  www.gretteassociates.com 
Geotech: Geoengineers  www.geoengineers.com/ 
Mechanical: Ecotope   www.ecotope.com 
Survey: Tackman   www.tackmansurveying.com

Chris Walter, @ChrisWPhoto, talked with Matt Hutchins about the significance of Accessory Dwelling Units (ADUs).

At CAST architecture, we have been focused on ADUs for more than a decade. They're fun to design, perfectly fit a niche for new housing in established neighborhoods, and provide many benefits for owners and residents.

https://www.youtube.com/watch?v=PJaLht9v5Yw

CAST’s Cedar Cottage is a City of Seattle Pre-approved DADU. Our vision is to adapt the high-design cottage, simplify it, and make it accessible.

See more at www.castcottages.com

“Part of the reason we love backyard cottages is just the opportunity. If you have a home with a possibility for a second house – it could be whatever you want it to be – a studio, a place for grandma, a rental, and having that flexibility is huge. We have people who have it as an Airbnb, or a long-term rental, as a place for their kids and then their retirement home. This flexibility is fantastic. It opens up so many opportunities in this great city.”         -- Matt Hutchins, AIA, Certified Passive House Designer

Backyard cottages = Flexibility and Opportunity

Published at Seattle’s Daily Journal of Commerce https://www.djc.com/news/ae/12162400.html

Give Middle Housing a shot!

Matt Hutchins’ comprehensive discussion, at Medium, of the Washington state Model Code for Middle Housing and how we can have it produce more housing in line with HB1110.

In HB 1110, the State Legislature read the will of the people and demanded that we tackle the housing crisis more proactively by allowing Middle Housing in most cities and towns. Washington State Department of Commerce has created a basic zoning template that supersedes local code if town planners balk at updating their own code to comply. The draft version of that Middle Housing Model Code is out for comment (comment here by December 6th!). I have analyzed the real world implications of how it would regulate new housing and how we can tweak it to better support the creation of townhouses, flats, and infill development.

Here are my recommendations:

1. Allow Middle Housing to be larger than single family houses: more lot coverage, smaller setbacks, and make them taller.

Diagram of current allowable single-family building sizes in 6 cities to illustrate that the Model Code’s Floor Area Ratio system is actually more restrictive.

It seems like an obvious point that the bulk of a building or buildings for up to 2, 4 or 6 households might be larger than one with just a single household, but a close look at some of the cities governed by this new legislation reveals that the draft code is MORE restrictive than current codes. It would effectively be a downzone in structure size in order to house more people. That isn’t a good trade, and for all the proof that Middle Housing has wide ranging benefits, we should have a code that supports it.

Middle housing is not just a bridge between the densities of single-family neighborhoods and denser areas, it is also a incremental increase in size between those building types.

2. Measure lot coverage, not FAR

There is a policy conversation about two methods for measuring building size: 1) lot coverage X height vs. 2) lot size X Floor Area Ratio. The draft code uses FAR for Tier 1 and 2 cities (the larger cities and the municipalities around them), and Lot Coverage for Tier 3 cities (smaller cities).

In the six Tier 1/Tier 2 cities I picked to analyze, five use lot coverage not FAR. The model code should follow suite. It is easy to implement, understand and compare apples to apples to existing codes.

Diagram of small cities buildable footprint illustrates how extra flexibility in lot coverage will translate to new housing for those communities.

Meanwhile Tier 3 cities, the code uses lot coverage to provide flexibility for how to develop successful infill housing, because lot coverage isn’t the critical threshold, the market is. I think this part of the Model Code will be actually be good for many smaller jurisdictions that are struggling with housing cost and access.

3. Set thresholds by looking at what can be feasibly built, not what might be politically expedient.

Illustration of all the new building types and whether they would be viable under the draft Model Code for typical lot sizes.

There is often a disconnect between how planners see development standards and how developers implement them. But ground truthing the code, when it is a draft, to understand the inevitable determinative impacts on the housing types that will get built, is the key to making the good development we want to see also the easiest to build.

Using a typical 5000 sf parcel zoned under the new code for 4 units, applying the FAR, we can build 4000sf. It becomes immediately apparent that many of the housing types we’re hoping for will never materialize and other types are going to yield less that then maximum number of units. Of the six types, I would expect the only feasible project is three townhomes. It is unlikely we’d generate very many 1000sf townhouses, 1200 sf triplex units or courtyard apartment buildings under the added cost of the IBC compliance.

The FAR needs to be up between 1 and 1.2 before we’d see the fourth townhome, or an apartment building.

4. Lean into making the most efficient and affordable housing form (small apartment buildings) the default infill Middle Housing type.

Our Spokane Six on the left works today, but wouldn’t be viable under the draft Model Code. This illustration shows that it would need to be 21% smaller.

Small apartment buildings have significant headwinds when it comes to financing, construction and operation. They also are the greenest, most efficient, context friendly and often least expensive forms of housing. They are also the best for preserving usable open space and landscape for large trees. They are the lowest common denominator building block for tackling the housing crisis. If the code works for those, then the other forms, like ownership townhouses, will work too.

When we tested our recent Spokane Grand sixplex, using the new Model Code, we discovered that we’d have to reduce the size by 21%, loose one of the porches, and downgrade the units from family friendly two bedrooms to one bedrooms. The pro forma for the development fell apart. If it can’t work in Spokane, with low land cost, reasonable construction cost, steadily climbing rents, there is very little chance these buildings would be viable in Puget Sound or other Tier 1 and 2 cities.

Without zoning incentives to build apartments, the market will continue to underproduce less expensive rental housing, even if we see some new ownership townhomes.

5. Reduce parking minimums.

Parking is always the cart that drives the horse. We have a housing problem not a parking problem.

So much has already be said and written about the high price of parking mandates, so I’m going to appeal to pure geometry.

On residential lots, designing for parking is step 1, before you even start to conceive of a building. For a sixplex on an alley, where parking is required, one space per unit arranged along the alley would require a lot width 56' feet minimum, which is wider than most urban lots. In order to provide the parking, much of the back yard is overtaken with pavement, more than 1/3rd of the site, lessening the quality of life for residents, creating stormwater issues and additional costs.

Without an alley, it is always worse; more than half of our typical lot is parking or driveway.

6. Regulating aesthetics on small neighborhood buildings is unnecessary micromanagement.

Strike this section. Or don’t. It is really so milquetoast that compliance isn’t an issue, but there will be lots of overlap/conflict with local codes that do regulate these simple aesthetics. Most townhouses are less that 20 feet wide — does a building’s design need to change every time there is a door? It is so fussy. In the interest of less bureaucracy, we should stamp out regulatory creep preemptively.

A Model Code that works.

The State’s Model Code is an opportunity to create a baseline for Middle Housing but it has to work. And this draft code would be so much more effective if it wasn’t second guessing its own mandate.

A final Model Code based on incremental increases of size over current single family structures, lot coverage not FAR, without parking minimums and design prescriptions, which allows builders the flexibility the make the homes people need, is the right direction forward for a statewide standard.

Cross-Laminated Timber Berm House in Washington's Methow Valley

The Berm House is a private residence that doubles as the common house and gathering space for a 19 house mixed-income community in Washington’s Methow Valley. The house is set into the landscape, with a panoramic view of the farmland down valley, but hidden from the road by a berm that ramps up onto and across the roof. 

The south-facing building orientation optimizes winter solar exposure coupled with large overhangs to protect from snowfall and the intense summer sun. The home is post and beam structure with a cross-laminated timber (CLT) roof prefabricated in northeastern Washington. The design incorporates Passive House principles including managing seasonal heat gain from solar exposure, advanced air sealing, and mechanical ventilation. Thermal bridges are minimized by wrapping the house in continuous external insulation, including structural EPS under the foundation, isolating the home from outdoor temperature swings. The earthen roof adds thermal mass, wildfire protection, and a promontory to take in the down valley vista.

The great room portion of the house was designed for friends and neighbors to gather, share meals, and be a social center for the community. Off the great room, a five-foot wide hall leads to three guest suites and the primary suite. The uncomplicated and efficient floor plan shows a clear division between the private and public spaces. The mechanical room, pantry, storage, guest bath, and laundry spaces are arranged along the berm side of the house’s section.

The material palette is predominately warm woods. The CLT ceiling and glulam posts and beams were manufactured nearby, and a coffee table and kitchen bar were crafted locally from a fir tree felled on the property. The exterior employs the Japanese shou sugi ban preservation technique. The boulders throughout the site and as part of the berm were pulled from the site and placed by the owner. 

Team
Owner: Lee Whittaker
Methow Housing Trust
Architect: CAST architecture
Contractor: Methow Valley Builders 
CLT: Vaagen Timbers
Concrete subcontractor: JR’s Five Star Concrete
Geotechnical Engineering: GeoEngineers

See more here.

STATE MODEL CODE FOR MIDDLE HOUSING IS MISSING ENOUGH HOUSING

BY MATT HUTCHINS (GUEST CONTRIBUTOR)

See full article and graphics here: https://www.theurbanist.org/2023/07/10/state-model-code-for-middle-housing-is-missing-enough-housing/

Commerce recently had a consultant create a form-based code, but the draft fails to advance housing abundance.

Now that Washington State’s Middle Housing bill (HB1110) has been signed into law, the next question is what implementation will look like — what kind of housing and where. The Department of Commerce has published a request for consultants to draft a model code that 1) will help jurisdictions write their own compliant middle housing code or 2) will supersede local zoning if they fail to implement their own in advance of the deadline (six months after their comprehensive planning update).

While we don’t know what cities and towns are thinking, we do have a picture of how Commerce is approaching the middle housing code. Last fall, Commerce hired a consultant to “inform about and assist local governments with middle housing policies, regulations, and programs.” 

In May, a focus group of planners, developers, and architects previewed a draft ‘Toolkit’ that illustrates four strategies that local governments could overlay on their residential zoning to allow new denser housing types within existing detached single family neighborhoods. The foundation of this toolkit is a form-based code meant to create ‘objective’ standards for middle housing that can be applied widely.

The issue is that the toolkit, rather than solving for affordability, feasibility, and the lowest carbon footprint, is primarily focused on crafting development guidelines that will keep new infill development the size of average houses and thus minimize the outcry from vocal neighbors. While this might be an easier to swallow approach for Washington cities and towns, it doesn’t scale up to address the deeper issues that HB 1110 was passed to address: the massive shortfall of new places for people to live. 

While Commerce’s original intent was to come up with instructive materials broadly applicable to most local governments, the effort lags behind what more progressive jurisdictions are already doing. But when we dig into the details, the toolkit suggests real reductions in development capacity: smaller footprints, bigger setbacks, and lower roof heights than are currently allowed in many Puget Sound cities. At its very worst, it will give slow-growth municipalities the option to select a new zoning overlay that is more prescriptive and restrictive, thus spoiling any chance that any new middle housing will be built.

Let’s go through the proposed new toolkit and look at some of the underlying flaws. 

• They state, “This toolkit does not provide standards for buildings taller than three stories.” For three of the four overlays in the Toolkit, buildings are conceived as two and a half stories with a height bonus for hip and gable roofs –  less that most of Washington cities’ least dense residential zones today. Rather than proposing an actual incremental increase, it ignores the status quo as a starting point. If you want a single pitch ‘shed’ roof, the 22-foot height limit is actually less than what we allow for a backyard cottage in Seattle today.

• Parking is mandated throughout the toolkit, a reversal for many jurisdictions that are moving away from required off street parking. Indeed one of the strengths of HB 1110 is releasing parking restrictions for new housing.

• Most overlay zones top out at four units per parcel, equivalent to Seattle’s second least dense zone, Residential Small Lot. Much of the ‘middle’ housing that is missing is between a house-sized triplex and the ‘5 over 1’ medium-sized apartment building. While this toolkit focuses on redundant standards for housing types we already allow, like townhouses and triplexes, it is silent on helping planners visualize appropriately-scaled urban buildings that might have between six to twenty units.

• Townhomes today, for better or worse, are the least expensive middle housing alternative available in the market, and the toolkit hamstrings their development with provisions that limit the number per building and the building length. The most successful rowhouse style homes on corner lots wouldn’t comply.

• The toolkit increases barriers for sites with multiple buildings on a single site, which would render many currently popular types of middle housing, such as detached townhouses, cottage clusters in Residential Small Lot zoning, and arguably even detached accessory dwelling units nearly impossible to build on compact urban lots.  

• The toolkit does not provide flexibility for sites that might want to preserve existing housing and build more. It assumes parcels are cleared rather than provide provisions for new buildings in the backyard, lot splitting, or additions that add units.

• While much of today’s urban design discourse is centered around neighborhoods where goods and services are accessible within a 15-minute walk or roll, the toolkit doesn’t have any provisions for mixed uses like daycares, commercial suites or corner stores.

• Finally, as one gets into the details of each overlay, it is chock full of reductions: larger setbacks, less lot coverage, less height, larger minimum lot areas, prescriptive design standards – each taking a bite out of the viability of future housing. When we compared a fourplex we’re currently designing in Spokane against the toolkit, we’d need to reduce the footprint by 32%, lose the front and back porches, and downgrade the 2-bedroom units to 1-bedrooms.  

• Unlocking the residential potential of urban land is critical if we’re going to provide the more than 1.1 million homes Washington State projects we’ll need over the next 20 years, and that means reintroducing multi-family housing types that exclusionary zoning has regulated out of existence.
  
  With this upcoming model code, we can take a good hard look at how new infill development is built, but we first have to move past the idea that middle housing is house-sized buildings carved into more apartments, or cottage clusters. Overall, the toolkit’s conceptual limitations and prescriptive ‘objective standards’ don’t reflect the real conditions of Washington neighborhoods.  

  A more serious effort would worry less about what neighbors might think and center our goals of housing abundance and climate action leading with middle housing types that work all the way up to four- and five-story mid-sized buildings in keeping with the best practices of urban planning around the world. Washington needs a flexible model code that supports the big picture goals of abundant housing.

An array of CAST’s detached accessory dwelling units (DADUs)

Statewide efforts to boost housing options make headway

This past legislative session, several bills made it through both houses and each will have long term benefits for the production of urban infill housing types such as cottages, ADUs, and small stacked apartment buildings.

HB 1337

The passing of HB 1337 expands housing options by easing barriers to the construction and use of ADUs.

·        legalizes two ADUs per lot in any configuration of attached/detached

·        legalizes an ADU on any lot size that’s legal for a house

·        legalizes ADU size up to at least 1,000 SF 

·        legalizes ADU height up to 24 feet

·        ends requirement for owner to live on site

·        caps impact fees at 50% of those charged on houses

·        lifts parking mandates within 1/2-mile or 15 minutes from transit stop

·        prohibits design standards or other restrictions more stringent than what applies to the main house 

·        legalizes ADUs to abutting property lines on alleys

·        legalizes ADUs in existing structures that violate current rules for setbacks or lot coverage

·        prohibits requirements for public right of way improvements

·        legalizes the sale of ADUs as condominiums

HB 1110

The Middle Housing Bill will mandate that medium and large cities create development standards for their lowest density zones to accommodate more housing.  For Seattle, it means:

·        Up to 4 units on any parcel not previously limited by an HOA or PUD.

·        Up to 6 units on parcels that are within ½ mile (a 10 minute walk) of frequent or fixed transit

·        Up to 6 units on any parcel if 2 are designated as affordable. 

The form that these new housing types will be open ended, but the Department of Commerce is busy developing a model code for cities to use as a starting point.  The deadline for cities to comply is 6 months after their next comprehensive plan cycle (for Seattle that is mid 2025). 

Spokane Four

As one of the region's leading voices for abundant and affordable housing choices, we have been advocating for backyard cottages—accessory dwelling units (ADUs)—since Seattle first considered them citywide in 2009.

More efficient land use is critical to address our housing crisis, climate change, and persistent inequities in access to housing opportunities. Modest infill houses like ADUs are a key strategy to empower citizens to provide new housing, build generational wealth, and leverage taxpayers’ investment in infrastructure, transit, schools, and parks. 

Seattle Architect CAST partners with The BLOCK Project

CAST has partnered with The BLOCK Project which builds fully equipped, healthy homes for people experiencing homelessness.  

We are excited to have just permitted our second BLOCK Project home!

BLOCK Homes are permitted and placed in homeowners' backyards throughout Seattle. This model gives residents a place to call home and our communities an opportunity to make a real difference in supporting our unhoused neighbors and addressing the issue of homelessness together.

Their mission: To inspire deliberate relationship building and community engagement as a pathway to ending homelessness.

www.the-block-project.org
@facinghomelessness