Waltier Homes’ new podcast covers all things Seattle real estate and development. We’re moving past the era of just cottages and ADUs. We’re talking about density that scales.

Listen to the full podcast here:
Waltier Homes Building Seattle Podcast with guest Matt Hutchins

In the episode, @waltierhomes sits down with our first guest, Matt Hutchins - Principal and founder @cast.arch, who served as AIA Seattle President 24-25, and is a Passive House Certified Designer, just to name a few of his credentials. Matt is extremely involved in Seattle zoning and urban planning. In this podcast, we break down some of the massive potential in neighborhood residential zoning:

- Single-Family Residence lots to mixed-use building + flats above

- HB 1337, which aims to address the housing affordability crisis by easing regulations on accessory dwelling units (ADUs), allowing for more diverse housing options and increased accessibility.

- Density and stacked apartments - As soon as you start getting a little denser, if you can share amenities, aggregate the open space, and have areas like gardens, and space for a barbecue and gazebo

- Duplexes in the backyard of Single-Family Residences

- Highest and best use - rezoning creates a lot of incentives for stacked flats, duplexes, and triplexes, you can actually get incredible density

A newly completed pre-approved Cedar Cottage, built by Waltier Homes. This 467 square foot DADU (Detached Accessory Dwelling Unit) is home for grandparents on multigenerational property.

DADUs are transforming the housing landscape in urban areas. These self-contained small homes can be attached or stand-alone and are becoming increasingly popular in cities grappling with housing shortages, rising costs, and shifting lifestyle preferences.

As one of the region's leading voices for abundant and affordable housing choices, CAST has advocated for backyard cottages—accessory dwelling units (ADUs)—since Seattle first considered them citywide in 2009, and our Cedar Cottage is pre-approved by the City of Seattle.

We want as many people as possible to benefit from a mix of housing options.

More efficient land use is critical to address our housing crisis, climate change, and persistent inequities in access to housing opportunities. Modest infill housing, such as 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.

RESOURCES
City of Seattle ADUniverse
CASTcottages.com

ADUs and DADUs

Help Housing Shortages
The surge in demand for housing has put significant pressure on urban neighborhoods, where space is limited, and housing affordability is a critical issue. ADUs and DADUs offer a practical solution by increasing the housing stock within existing neighborhoods.

Affordability + Flexibility
ADUs and DADUs provide an affordable alternative for renters and homeowners alike. Homeowners can use these units as rental properties, offering housing at a lower cost than traditional apartment units. They can also serve as multi-generational living spaces, allowing families to stay connected while maintaining privacy. For many, ADUs are a way to downsize without leaving their neighborhoods, contributing to economic diversity in communities.

Ease Zoning Regulations
Cities across the US are revising zoning laws to encourage the construction of ADUs and DADUs. These policy changes make it easier for homeowners to build these units by reducing permitting costs, relaxing parking requirements, and increasing maximum allowable sizes. In Seattle, for example, pre-approved DADU plans streamline the process, saving time and money for homeowners.

Sustainability
These small homes align with urban densification goals. By utilizing existing infrastructure and minimizing the need for new developments, these homes help reduce urban sprawl. Additionally, their smaller size typically results in lower energy consumption.

Enhance Community Character
Thoughtfully designed DADUs can blend seamlessly into existing architectural styles, adding diversity to the housing stock while preserving the integrity of the neighborhood.

📸 Northlight Stills & Motion

Matt Hutchins presented Zoning Changes in Seattle – Guiding Our Growth to 2040 at West Seattle Realty.

He covered topics like what kinds of new development we can expect (from cottages to stacked flats), the urban design of Neighborhood Centers and Corridors, and how we turn the growth we’ll have into the city we want to live in…

Watch the recording here: https://www.youtube.com/watch?v=te4pQaMm74E

Topics covered:
- Where is Seattle in the zoning process?
- Seattle’s changing population and demographics
- What does “affordable housing” actually mean? And, how do we achieve affordable housing for a lot more people?
- New opportunities in Neighborhood Residential (NR)
- Forecast of Centers and Corridors legislation impact

We are honored to be a part of the FYRE team for the recently funded important space for youth in Washington state. 

The Foundation for Youth Resiliency and Engagement (FYRE) is an innovative grassroots organization serving young people 12-24 across Okanogan County, Washington. FYRE’s services include educational advocacy, supporting young parents, increasing accessibility to whole-person health services, and providing referrals and resources to youth experiencing homelessness and exploitation.

CAST is designing a residential shelter providing emergency and transitional housing for homeless youth. Located adjacent to FYRE’s existing building, the facility will also include various support functions such as shared cooking and social spaces, and intake/counseling offices. FYRE’s Village will serve several populations, such as expecting mothers and LGBTQ+ individuals. The design must accommodate complex security and licensing requirements, given the wide age range served by FYRE (ages 12-24) and length of stay (overnight to 24 months).

FYRE Village is designed to Washington’s Evergreen Sustainable Design Standard (ESDS).

TEAM
Foundation for Youth Resiliency and Engagement (FYRE) – owner www.okfyre.org
Office of Rural & Farmworker Housing – developer www.orfh.org
CAST – architect
RLB – cost estimating
NCW Land Surveying – survey

At only 392 square feet, the Sakura Cottage is an elegant solution for even the most difficult sites.  The recessed entry and light well provide protection and daylighting when situated along a property line or alley. The bedroom space can be closed off with a barn door, which makes it perfect for a guest room or a work-from-home office. 

1 Bedroom / 1 Bath
Net Floor Area: 392SF

The monoslope roof extends to create a deep porch on one side, adjacent to the open living room and galley kitchen.

The Sakura was designed with sustainability in mind, featuring wall and roof assemblies detailed to minimize air leaks, energy-efficient heat pump heating and cooling, low-VOC finishes, LED lighting, and no fossil fuels or foam insulation.

Context
The Sakura has a compact footprint that fits on even the smallest allowable lot. The living space is oriented to a patio that can face a side yard or an alley, depending on site, solar orientation, and owner preference. The house is designed to sit low on lots with some slope, respecting neighbors and daylight. This small footprint and shallow foundation works well with existing trees.

Sakura Cottage is designed with these characteristics:

ACCESSIBLE
Living on one level
Flush threshold at the entries
Galley kitchen allows side approach to all appliances
Flush shower thresholds for increased accessibility
Graspable door handles and cabinet pulls
Blocking specified for secure grab bar placement
2'-8" clear dimension for all doorways

LOW COST
Off-the-shelf 30-gallon electric water heater
Simple and elegant siding
Conventional wood framing over a concrete slab on grade is economical and easy to construct
No gas piping required
Choices allow for low-cost construction without sacrificing durability, function, or style

GREEN BUILDING
Heat Pump for heating and cooling
Spot Energy Recovery Ventilator (ERV) to provide whole-house ventilation, maintain temperature, and regulate humidity
Deep overhang at porch is ideal for passive solar heat gain, allows winter daylight, summer shade, and protection from rain at the entry
Monoslope roof is ideal for solar and rainwater reuse.
Induction cooktop; no fossil-fuel appliances.
Metal Roof and siding: 40-year warranty, recyclable material, rainwater harvested isn't contaminated with asphalt or plastics
Rainscreen siding system key for durable drying wall assembly

WORK FROM HOME
Perfect size for a work-from-home studio/guest quarters
One bedroom with a privacy partition allows the user to create separation between working and living environments

PRIVACY
The house's outward orientation is focused on one side, which can be oriented away from neighbors or toward principal residence or alley, or to solar orientation, depending on the owner's preference.
Recessed entry provides protection if built right on alley
One-story height limits shadow and visual impact for neighbors
Light well brings sun where proximity to lot line might otherwise limit windows


See CASTcottages.com for more information.

Matt Hutchins, AIA, CPHD

Four case studies on how new zoning incentives align with demographic shifts to meet housing demand.

Now that the dust has settled, we can game out how the One Seattle Plan’s nearly final development standards with open up new opportunities for affordable and accessible neighborhood housing. The flurry of late amendments created incentives for higher-density stacked flats, additional floor area, more accessible units, taller buildings, and parking reductions that could fundamentally evolve the neighborhood’s next generation of housing. The recent history of Seattle’s housing market has been split into three housing types: single-family houses few can afford, townhouses, or five-seven story apartment blocks partitioned into hundreds of studios and one bedrooms. New middle housing can split the difference: Larger units in smaller buildings, with more options that appeal to wider demographic trends, distributed throughout more walkable neighborhoods, built to today’s higher green standards, at a reasonable risk, cost, and return.

More project types, both market and subsidized, are now viable at least on paper in the city’s Neighborhood Residential zone. Seattle’s housing needs are evolving, and using the incentives to build the kinds of projects that would fill growing niches that aren’t being served currently is an exciting prospect.

Each of these concepts starts with Seattle’s typical 50' x 100' residential lot, with an alley. Since parking is no longer required for units under 1200 square feet, and wouldn’t fit anyway without budget-busting below-grade structured parking garages, we haven’t included any fully parked concepts. Finally, each of these concepts has a similar boxy form — there is a reason that small apartment buildings such as these were the mainstay of ‘naturally occurring affordable housing’ for generations — they can be wonderfully efficient housing solutions.

Case 1: Greener Market Rate Flats for Lease

During the run-up to the vote on the various amendments to the One Seattle Plan, public testimony became a zero sum game between new housing and tree canopy. Amendments that preserve existing Tier 1 and Tier 2 trees, achieve a higher quality of landscaping using the Green Factor, and plant for future canopy in addition to current requirements for street trees, mean that developments with well-placed large trees on the periphery can unlock an additional building story. In this case, designing around a Tier 2 tree isn’t a compromise — it is an unlock that allows enough height and floor area to build eleven two-bedroom flats.

In our development work, we expect two-bedroom apartments to be snapped up by households with children, but we’re seeing older households who want long-term options to flex space between working from home, caring for elders, or reducing the cost of living for the next generation. And if we can build hundreds more buildings like this, we can reduce the scarcity that makes affording a two-bedroom seem out of reach for many of the 56% percent of Seattle households who rent.

The form factor of flats tends to be more compact, and single-stair buildings further optimize their efficiency. The case study approaches the maximum building size without hitting the maximum lot coverage, and provide 225 square feet of outdoor space per household, with generous balconies for every unit. Unfortunately, there isn’t any additional incentive for greener buildings under the new zoning, but it helps that the baseline under Seattle’s stringent energy code is already one of the best in the nation. Just adding households to established neighborhoods within walking distance of transit and amenities is great for lowering our city’s per capita carbon footprint.

Case 2: Larger Ownership Flats:

Zoning incentives to increase allowable floor area for new stacked flats outpaced the density limits a bit, creating an opening for larger units. While conventional multifamily development is focused on packing more units into less square footage, leading to such innovations as windowless bedrooms, the new rules make designing more spacious flats similar in size to townhouses and ADUs.

With longtime homeowners aging out of the space and responsibility of a single-family detached house, downsizing Boomers and Gen-Xers will be looking to convert some of their equity into a lower-cost, less commitment flat without having to leave their neighborhood. One of the biggest incentives discounts more accessible ‘Type A’ units, great for aging in place, entirely pulling them out of calculations for density, lot coverage, and floor area ratio. With the extra development capacity, maybe we can spring for an elevator and still make it pencil by marginally increasing the sales price of the units.

Flats with more smaller bedrooms, like the three-bedroom units in Case 2, are a good fit given how households are changing. The trend is that more households include either an aging parent or an adult child. That extra bedroom means flexibility and stability for families over time. Concerns about housing affect couples’ decision to whether to have children and family friendly buildings like Cases 1 and 2 can make it less daunting.

Seattle isn’t producing enough ‘starter’ homes to satisfy the demand, locking out those who’d like to step up into ownership and locking in those who’d like to downsize but can’t find anything to move from their single-family house. Building stacked flats works both to create elasticity in the housing market (price reductions responding to supply increases) and flexibility for households changing situations.

We are hearing anecdotally that this scale of building is also appealing to those who would love to work together with friends to co-develop, build, and live together in an intentional community under a co-op or condo ownership structure, but development is a risky venture and few will take the leap.

Case 3: Subsidized Ownership Flats

Seattle’s stock of subsidized affordable housing is concentrated in the areas designated as urban centers, but the need is much more broadly distributed. The new Neighborhood Center place type is going to expand the territory where typical subsidized affordable housing can be built at the scale that works for most service providers, but our local Habitat for Humanity Seattle-King County has been deploying a scaled-down solution that can provide 10–20 households with ownership opportunities for those making less than 80% of the area’s median income. One-bedroom homes, such as in Case 3, are priced from the mid $200Ks, equating to a monthly all-in payment of $1800-$2600.

Using incentives for affordable housing, stacked flats, Green Factor landscaping, Type A accessible units, and lot coverage, non-profit affordable housing providers can fit up to 16 one-bedroom units on a parcel and still have space for 174 square feet of outdoor space per resident.

Over the next ten years, the fastest growing segment of new households will be single-person households over age 65. Rather than be isolated in a detached house, a building such as Case 3 (add an elevator) offers community, affordability and stabilty. Because a building this size can be built nearly anywhere within the new Neighborhood Residential zone, over time we can hope to see senior housing pop up in easy walking distance of bustling Neighborhood Centers.

 Case 4: Subsidized Rentals + Child Care Center

Seattle desperately needs more child care, and the process to certify a new center is rigorous. In order to justify the investment, the basic template is four classrooms, each with twenty kids, plus administration and facilities, and a space for outdoor play. If a provider can assemble two adjacent NR lots, like in Case 4, the ground floor area is the perfect size. This is essentially what many of our larger affordable housing projects are doing — anchoring the ground level with a child care center, then drawing kids from both the housing above and the surrounding neighborhood.

The real benefit of Case 4 is that this project might take 30 months instead of four or five years for a larger project, require fewer funding sources for the affordable housing, and have tens of thousands of potential residential sites to choose from rather than having to compete with other developer interests in the urban centers. Being in the neighborhood might also induce parents to walk their kids to the center, so we aren’t mixing idling car exhaust, impatient drivers, and vulnerable kids.

Moving Forward

These four case studies illustrate how new zoning incentives can generate more housing, more affordable housing, more accessible housing, for more more types of households. I am looking forward to Seattle City Council’s passing these incentives later this year, and welcoming some new neighbors in the near future.

Link to article on Medium: https://medium.com/@matthutchinsaia/making-seattle-neighborhoods-more-accessible-by-design-c1d195fab124

We celebrated the ground breaking for the Wildrose Apartments in the Methow Valley on October 23rd, 2025. CAST is working with the Housing Authority of Okanogan County on the much-needed Wildrose Apartments in Winthrop, Washington. This complex will provide 22 new affordable housing units. Homes will be a mix of one-, two-, and three-bedroom apartments, accommodating families, seniors, and young adults.

The apartments are distributed into three 2-story structures surrounding two sides of a large commons that serves both communities. Both upper and lower units provide outdoor space facing the park, energizing the open space with many sources of activity around its perimeter. The footprint and envelope of each building is kept simple to reduce cost; secondary porches and balconies add visual interest while providing solar shading and weather protection.

During our initial pre-design / Master Planning phase, we sought ways to consolidate the site plan by stacking units and minimizing auto circulation. This allowed us to create a communal open space almost three times larger than what was originally considered in the Feasibility phase.

TEAM
Owner: Housing Authority of Okanogan County www.okanoganhousing.org
Developer: Office of Rural and Farmworker Housing www.orfh.org
Architect: CAST
Contractor: Cascade Central Construction
Civil + Structural Engineer: Facet
Landscape Architecture: Lyon Landscape Architects
Electrical Engineer: TFWB Engineers
Mechanical Engineer: Berona Engineers, Inc
Envelope: Testcomm LLC
Survey: Tackman Surveying
Geotechnical: Nelson Geotechnical Associates. Inc.

With generous support from:
Methow Housing Trust
Community Foundation of North Central Washington
Rural Community Assistance Corporation
Washington State Department of Commerce
Washington State Housing Finance Commission

Photos: Mitchell Image

Under construction… With the Methow River Retreat, we conscientiously limited its footprint to minimize disruption of the riverfront site. This careful approach allows the home to reflect craft and integrate passive design solutions while sitting lightly on the land.

With a keen focus on preserving views in all directions and ensuring privacy, window placement is carefully planned for maximum impact. Low leakage, high R-value European tilt-turn style windows have wood interiors and aluminum exteriors, providing efficiency, durability, and beauty.

A ground-source heat pump that leverages the earth's consistent temperature was selected for enhanced efficient heating and cooling.  Spray foam is used sparingly and is purposeful, prioritizing condensation control at the roof while minimizing environmental impact. To maximize solar panel efficiency, the south-facing roof orientation is complemented by a battery system for an uninterrupted power supply during power outages.

Energy-efficient appliances were selected. From a combination heat pump washer/dryer to an induction range, each choice reflects efficiency and sustainability.

TEAM
Architect: CAST
Builder: Bjornsen Construction
Structural Engineer: Harriott Valentine Engineers
Biologist: George Wooten

See more: www.castarchitecture.com/methow-river-retreat

This off-grid cabin, nestled in the hills on a 5+ acre site bordering U.S. Forest Service land, is 30 minutes from Logan, Utah. The home makes the most of its setting, offering expansive views in every direction. A southwest-facing bank of windows frames the surrounding landscape views, bringing in abundant natural light. The cabin is designed to operate entirely off the grid, with a solar array and backup generator.

The structure’s orientation, placement of glazing, and the depth of roof overhangs are designed to optimize solar gain in winter, while providing shade during the hot summer sun—an efficient and responsive strategy. A solar array with a backup generator powers the home.

Firewise design strategies:
- rock and concrete perimeter
- weathering steel siding
- metal roof (also designed to retain snow )

Built to meet the challenges of its rural location, this cabin demonstrates how modern off-grid living can be resilient and deeply connected to place.

See more: www.castarchitecture.com/logan-canyon-offgrid-cabin

Collaborating with Berger Partnership, we built on a vision to redevelop this underutilized park to take advantage of its spectacular location and transform it into a regional asset.

The intent was to revamp a few dilapidated baseball fields with additional features to encourage use by a wider audience. The big move is an overlook deck that stretches towards the Chelan dam, gorge, and surrounding mountains and offers elevated views back towards the baseball diamonds.

An overlook was designed to provide a view of the dam and the surrounding mountains that had been unavailable to the public. We combined functions whenever possible, with the deck also serving as a roof to the gathering space below, stacked basalt seating relating to the surrounding geology, and finally, a sloping lawn that adds minor league stadium-style seating looking over the baseball fields. The roofs of the dugouts and central concession station also perform double duty as extended shade platforms to provide weather protection to visitors.

Enterprise, by Ahmad Abu-Khalaf

CAST contributed to this issue, highlighting recent updates on regulatory reforms and financing innovations aimed at the development of low-density multifamily housing.

View a PDF of the Issue Brief Here

What is low-density multifamily housing? There is no single, definition of lowdensity multifamily (LDMF) housing, which is also called gentle density housing or missing middle housing. LDMF housing varies across state and local housing markets depending on the market’s residential development patterns.

The effective definition of LDMF housing may also be influenced by what is allowable under current land use and zoning requirements. The effective definition of LDMF housing may also be influenced by what is allowable under current land use and zoning requirements.

On the financing side, several private entities have launched lending products tailored to LDMF housing. These loans are designed to provide debt capital for multifamily developments with small- to medium-sized loan balances.

Despite this progress, more work needs to be done to significantly boost LDMF housing nationwide. A much larger number of jurisdictions must adopt regulatory reforms that would lead to a broader regulatory landscape supportive of LDMF housing, enabling the housing industry to build it at scale.

Unlocking underutilized land zoned for single-family development to allow for LDMF housing has the potential to help jurisdictions ease their housing markets’ supply and affordability issues. However, boosting LDMF housing nationwide requires addressing the regulatory and financial barriers to creating this type of development at scale.

University Cooperative School is the first school to be approved as Retrofitted on the City of Seattle’s URM list.

The City of Seattle has recognized University Cooperative School for successfully achieving "Retrofitted Unreinforced Masonry (URM)" status. Over eight years, CAST, Swenson Say Faget structural engineers, and the project team completed the required work and documentation, ensuring the school meets the necessary standards, and updated its status on the City's list of structures previously requiring evaluation and potential retrofitting under the upcoming URM Ordinance.

TEAM
Client: University Cooperative School
Architect: CAST
Owners Rep: Westlake Consulting Group
Contractor: Sellen
Structural: Swenson Say Faget ssfengineers.com
Electrical: TFWB
Estimating: Rider Levett Bucknall www.rlb.com/americas
Special Inspection: Terracon