Introducing CAST’s Infill Housing Toolkit: We put together recent, current, and future projects to showcase strategies and case studies for abundant housing infill development.
Site Typologies
Constrained Lots
Typical Infill Lots
Large, Assembled Lots
Design Features
Single Stair
Stacked Flats
Low-Energy Design
Low-Carbon Building
Diverse Unit Mix
Open Space
ECHO, a 10-unit apartment building in the Eastlake neighborhood of Seattle, is now a Design Certified PHIUS (Passive House Institute US) Core 2021 project.
This apartment building will replaces a single-family structure in this residential urban village, adding missing-middle housing. It utilizes the stacked flats concept which pushes the bounds of the single-family envelope but maintains an urbanism-friendly street frontage.
The two homes on the ground floor are both fully accessible. And, the top two units have high ceilings with lofted sleeping areas.
High-performance design elements include: thermal control, airtightness and moisture control, balanced ventilation, and high-performance glazing.
TEAM
Developer: West Crescent Advisors, LLC, Nancy Melton
Architect: CAST
Passive House Institute US: @passivehouseinstituteus
Builder: Carrig Construction @carrig_construction
Project Consultant: Woodworth Construction Management LLC, Lydia Anne, @woodworth_built
Civil Engineer: Davido Consulting Group, Inc. @dcgengr
Structural Engineer: Harriott Valentine Engineers @harriottvalentine
Mechanical Engineer: Ecotope @ecotope_inc
Envelope Consultant: B.E.E Consulting, LLC
Electrical Engineer: TFWB Engineers, Inc
Windows: Alpen Windows – Passive House Certified
Landscape Architect: @karenkiestlandscapearchitects
Arborist: Moss Studio
Geotechnical Engineer: PanGEO, Inc.
Surveyor: Terrane @terranesurveying
Third party verifier: Balderston Associates
ON THE BOARDS - METHOW VALLEY’S RIVERSMeet WINTHROP proposed MIXED-USE BUILDING
RiversMeet, a proposed 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.
CAST’s client, Peter Goldman, as part of his development proposal, intends to request the town make zoning changes to allow for long-term rentals in the commercial district. 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.
Team
Client: Peter Goldman and Martha Kongsgaard
Architect: CAST architecture
Builder: North Star Construction Company www.Northstarbuilds.Com
Civil & Structural: DCG 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
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.
New tribal Hatchery & Beach Shelter
At the beach at Point Julia on land occupied by the tribe since time immemorial, the Port Gamble S’Klallam Tribe’s Hatchery and Beach Shelter combines pragmatic uses with symbolic content. Salmon fishing is central to the Port Gamble S’Klallam Tribe’s traditional identity and its contemporary outlook. The new 1,800 SF two-story building accommodates both office and utility space for the Port Gamble S’Klallam Tribe’s salmon hatchery program, along with a separate open-air structure used by the Tribe’s commercial fishing operations. This project recognizes the cultural importance of both the place—a focal point of their history—and the program, while providing solutions to allow these activities to flourish in the 21st century.
The lower level of the Hatchery houses a garage, maintenance shop, and egg-incubation room with equipment that is both durable and moveable. The upper floor contains offices, water-quality testing, and filtration equipment. The conference room on the southwest corner can be entered separately, accessible to the wider community.
The new hatchery forms a gateway to the beach from the landward side, and the beach shelter is the Tribe’s front door on the sea. It will provide a work area for fishermen who pull their boats onto the beach and will also provide recreation space for the community. On the beach between the two structures, the native landscape is being restored, along with traditional edible and medicinal plants, and salt-tolerant erosion control plantings.
See more here.
TEAM
Owner: Port Gamble S’Klallam Tribe
Architecture: CAST architecture
Photography: Lara Swimmer
Contractor: Pacific Civil & Infrastructure
Geo-tech: Robinson Noble
Structural: Swenson Say Faget
MEP: Glumac
Civil: Cannon
Landscape Architect: Pacific Landscape Architecture
Windows: Jeld-Wen
Archeologist: Willamette Cultural Resources
Survey: AES Consultants
Intake System Engineer: Kleinschmidt Group
Specifications: Applied Building Information
Art/light installation: S’Klallam artist Jimmy Price
Conference table / Entry bench: Craig Kohring
A “People Place” by Design
The Mazama Public House was conceived with community in mind.
“The long communal tables were always indicative of the way we were thinking about the place. You come in and you’re part of the community. You share a table and suddenly you’re in conversation with a person you’ve never met before. It’s a fun opportunity.”
-- Stefan Hampden, CAST architecture
See the full article here on Issue.
This pub is the new gathering spot for the community of Mazama, at the north end of Washington’s Methow Valley. The 1,868 square foot public house is designed to seat 56 and another 50 outside with built-in benches on the four-season covered patio. In warm weather, a garage door system opens for a seamless connection to the outdoor decks. The height of the shed roof and the expansive windows on two sides are sited to take advantage of natural light and views toward Goat Peak. The interior features wood beams punctuated by blackened steel and concrete floors. Custom tables and bar slabs were crafted from locally sourced Douglas-fir. Outside, blackened steel will accent the wood structure. The siding is a dark-stained, rough-sawn vertical channel shiplap.
Green design features the use of highly durable siding materials including a mix of locally harvested wood from the Methow Valley and Boise Cascade products. The generous overhangs were designed to protect the siding from wear and tear. Full LED lighting was installed.
@mazamapub
Architect: CAST architecture
Owner: Grumpy Goats, LLC
Operator: Old Schoolhouse Brewery @oldschoolhousebrewery
Contractor: Bjornsen Construction, Tom Bjornsen
Structural: Harriott Valentine Engineers @harriottvalentine
Lighting: LightWire @ltwire
Windows & doors: @sierrapacificwindows
The Methow Valley’s Riverside Winthrop Mixed-use project – On the Boards
“This is an amazing gift to the community. I hope everyone will look for ways to make sure it happens.”
-- public meeting attendee
This mixed-use project, at the east side 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. The private development is driven by long-time Winthrop residents Peter Goldman and Martha Konsgaard and prioritizes doing right by the community on several fronts.
Given the housing crisis affecting the area, CAST is working with the town on zoning changes to allow for long-term residential rentals, and to integrate workforce housing into the project's program. At both a pedestrian as well as a vehicular gateway to the city, we are linking the town’s boardwalk to the Susie Stephens trail and the town's civic center on the south side of the river. We are working with the community to create an entry point to a public riverwalk trail system. Additionally, the project is envisioned as a template for how buildings can work within Winthrop's westernization code while striving for very high levels of sustainability and designing to passive house standards for the residential and office suites.
Riverside’s program will provide one 1-bedroom and two 2-bedroom residential units overlooking the river, with approximately 2,600 SF of pedestrian-level retail space which spills out into a public courtyard strengthening views and access to the river from town. The second floor incorporates 2,650 SF of office space, continuing the client’s tradition of renting below market rate to community non-profit businesses.
Team
Client: Peter Goldman and Martha Kongsgaard
Architect: CAST architecture
Builder: North Star Construction Company www.Northstarbuilds.Com
Civil & Structural: DCG 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