ADUs Bring Organic Growth to Suburbia, And We Desperately Need More Of It.
CategoriesArchitecture

ADUs Bring Organic Growth to Suburbia, And We Desperately Need More Of It.

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Accessory Dwelling Units (ADUs) mandated by the State of California override local planning regulations to permit a second unit on almost any single-family zoned property. The law also allows any single-family zoned lot to be subdivided into two parcels. Additionally, it allows ADUs to be built with just a four-foot setback or no setback at the new interior property line of a subdivided parcel, in contrast with most towns, which have setbacks of more than 7 feet, up to 30 feet. It also mandates very relaxed parking requirements or no parking if the project is near public transit.

Is California paving the way for ADUs across the US?

ADU Portland. Exterior view and section.

ADU Portland. Left: Exterior view; right: building section. Courtesy of Webster Wilson Architect. Image by Caitlin Murray.

ADUs: A Solution for Affordable Housing Shortage

California has long grappled with an acute housing shortage, especially affordable housing. Local governments, under the thrall of NIMBY residents trying to preserve the rural/suburban “character” of their communities, have not been very cooperative with state goals for new housing.

Local planning departments bristle at their authority being usurped by the state, but for growing numbers of people, these ADU rules offer welcome flexibility and opportunities for growth in a place that is building better, more stable communities, providing housing, and stemming sprawl.

ADUs for Families of all Sorts of Forms

The endless swaths of single-family houses spreading across the hills and valleys of suburbia are the physical manifestation of a culture that fetishized the nuclear family — and conspicuous consumption. But, a simple nuclear family unit has never been anywhere near the universal living arrangement and is becoming ever less universal. Homeowners are using the ADU rules to build houses for a kaleidoscopic variety of living arrangements and “families” of all shapes, types, and sizes.

Drone view of suburban Utah town and Modern addition to existing house in the Salt Lake City area

Left: Drone view of similar houses, driveways, and yards in the Utah suburbs. Original public domain image from Wikimedia Commons via rawpixel; right: Modern addition to an existing suburban house in the Salt Lake City area. Image by Brian Babb via Unsplash.

From Granny Flat to Rental Property

Having a place for “granny” is hardly the only use for these units. Homeowners may be looking for something affordable for grown children and their partners that doesn’t force them to move hours away. They’re also looking for flexibility and future-proofing. What is grandma’s house today can become an income rental property that allows a homeowner on a fixed income to afford to stay in place.

Family party BBQ. Chicago.

Family party BBQ. Chicago. Image by Tela Chhe via Flickr.

Building Stronger Communities

The law allows a single-family zoned parcel to be subdivided into two parcels, and each of these parcels to have two units, so up to four units can be made from a single-family house. This lets people do what traditionally has often been standard operating procedure: houses are extended to accommodate growing and branching families. It can help keep extended families together, which in turn, builds stronger communities.

Breaking the Monotony of Suburban Architecture

These new units are also changing the look and feel of suburbia for the better as well. Blank two-car garage doors are being replaced by lively facades of windows and openings. The tighter setbacks help give the remodeled houses a different rhythm and feel on the street, breaking the monotonous sameness of cookie-cutter ranchers.

Courtyard DADU, Seattle, WA.

Courtyard DADU, Seattle, Washington. Left: View from the courtyard; right: floor plan. Courtesy of Robert Hutchison Architecture. Photo by Eirik Johnson.

YIMBY!

Until the advent of professional planners, towns and cities almost always grew and became more densely developed in small steps in exactly this way. This laisser-faire method of “planning” has produced most of the best, most treasured urban landscapes across the world. Our banal suburban sprawl may yet be redeemed through organic in-fill growth done by and for residents who are increasingly proclaiming YIMBY! (Yes, In My Back Yard).

This article was written in collaboration with Californian architect Ian Ayers.

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Reference

North Arrow Studio designs a playful, birdhouse-like ADU in Austin
CategoriesArchitecture

North Arrow Studio designs a playful, birdhouse-like ADU in Austin

North Arrow Studio has completed a compact, corrugated metal accessory dwelling unit in East Austin’s Chestnut neighbourhood featuring a custom, circular pivot window that is reminiscent of the round opening in a birdhouse.

Aptly named the Birdhouse, the 900-square foot (84-square metre) ADU shares a narrow 5,900-square metre (550-square metre) lot with a 1939 single-storey house and three large protected pecan trees.

Corrugated metal accessory dwelling unit with a circular window
The Birdhouse is an accessory dwelling unit in East Austin

North Arrow Studio’s principal architect Francisco Arredondo described the two-bedroom, two-bath house as “simplicity carried to the extreme”.

“There’s simplicity in the footprint, the massing, and the material palette throughout,” Arredondo said. “But it’s also a smart little house that makes me smile.”

Corrugated metal structure by North Arrow Studio placed around trees
It is strategically placed around trees to create a courtyard

The home was strategically placed around the trees to create a courtyard between the main house and the ADU while providing privacy for the separate living quarters.

The L-shaped plan features a bedroom, bathroom, kitchen and living room featuring a roll-up garage door on the ground floor, all wrapped around an external pecan tree.

White walls of ADU with roll-up garage door
A roll-up garage door features in the living room

Upstairs, the main suite sits within the vaulted ceiling of the double-gabled form. Four five-foot (1.5-metre) diameter circle windows sit under each gable and use the surrounding tree canopy for privacy.

“They create a resemblance to a traditional birdhouse and bring a sense of whimsy to the design,” the studio said.

Circular pivot window in gabled roof
The main suite sits within the vaulted ceiling of the double-gabled form

One of the custom-fabricated steel windows serves as the required egress for the room.

“We began with a pivot design and worked our way towards a final swing design that opened up to the pecan tree’s canopy,” the team explained.

Bathroom with red tiles and small circular windows
The rounded-window motif carries throughout the house

The rounded-window motif carries throughout the house with miniature custom steel circle windows.

“Strategically selected walls are curved to soften edges and draw you into the spaces,” the studio said. “Interior finishes are simple and restrained apart from a few accent walls that give life to each room.”

Neutral colours in bedroom of ADU
Neutral colours decorate the living spaces

The monotone ADU is wrapped in light corrugated metal that “is a nod to the many metal sheds and accessory buildings already found throughout the neighborhood, but with a modern and playful twist”.

The soft, rounded edges and neutral colour complement the existing house and provide an accent along the alley, and the metal runs up the walls and becomes the roof material as well.

In the courtyard, a curved polycarbonate wall brings light into the hallway and creates a softly glowing, semi-transparent effect.

Corrugated metal was selected for its sustainability and resilience as the envelope is 100 per cent recyclable, repels sun and heat in Texas summers and is durable and low-maintenance, according to the studio.

Corrugated metal structure with circular openings and a gabled roof
Corrugated metal wraps the structure

“Working with a tight budget and constrained footprint can be very helpful in creating a story for the design,” the studio said. “The constraints begin to guide you and lend opportunities to be creative with traditional materials and spaces in ways that typically wouldn’t be considered.”

In 2014, North Arrow Studio created a stilted home in the Texas Hill Country that references Mies Van der Rohe’s glass Farnsworth House.

The photography is by Chase Daniel.


Project credits:

Builder, developer, owner: Brita Wallace, Digs ATX
Styling: Ben Newman Studios

Reference

Zero Accessory Dwelling Units (ADU): Low Income Housing that Works
CategoriesSustainable News Zero Energy Homes

Zero Accessory Dwelling Units (ADU): Low Income Housing that Works

We all know there is a considerable lack of affordable housing in the U.S. and that addressing it effectively has been challenging. Now that many states and municipalities are altering their zoning to allow Accessory Dwelling Units (ADUs), there is a new opportunity to expand truly affordable rental housing – building low, cost zero energy ADUs – sometimes referred to as in-law apartments, garage apartments, attic apartments, tiny homes, or casitas. But how to make them truly affordable?

Small ADUs are Affordable

By their very nature, ADUs will cost less to rent because they are smaller, and building them uses fewer materials.  This is even more likely in an above the garage, basement, or attic ADU where existing structural elements can be used. They also have no land costs because they are built on an existing lot or above an existing garage. And there are no landscaping costs other than restoring any construction disruption. Sewer, water, and electricity are close at hand.  And, if they are zero energy ADUs, they will need no gas hook-up.  More importantly, they will have no, or almost no, energy bills for their residents.

Zero Energy Bills

There are two legs to affordability.  One is the rent – the other is the monthly utility bill. The second one is almost always overlooked when considering affordable housing, but high energy bills can play a devastating role in making an ADU rental unaffordable.  Zero Energy ADUs solve that problem and offer a more truly affordable rental.  The challenge is how to get to zero at least cost, so the rent can be kept low.

Cost Cutting Zero ADU Construction 

The first step in low-cost zero energy construction is conducting energy modeling on the planned structure.  Energy modeling will help select the lowest cost mix of energy-saving measures such as insulation and air sealing, energy-saving equipment, and solar. For example, energy modeling and price comparisons will quickly determine whether it is more cost-effective to use a heat pump water heater or add some additional panels and use a standard water heater – or whether to use insulation with a higher or lower u-value.

There are other potential savings related to the smaller size of an ADU.  Windows are expensive. Locating them to optimize light and views, and eliminating or reducing them where they are not needed, may allow smaller glazed areas. Since mini splits can be ductless, there is no need for ductwork.  Most ADUs can be heated and cooled with one small unit, which is quick and easy to install.  Since heat pump HVAC systems should never be oversized, smaller ones are usually the best choice. 

In small homes, such as ADUs, energy or heat recovery ventilation systems can be installed without ducts, using a Lunos e2 through-the-wall HRV or a Panasonic Whisper Quiet ERV to provide fresh filtered air. The size of the water heating system can be tailored to a smaller number of inhabitants. A smaller 30 or 50-gallon heat pump water heater is an excellent but more expensive option. Using a small well insulated standard electric water heater with added solar panels may be less costly. An even more economical option might be using one or two-point of use tankless electric water heaters – one in the bath and one in the kitchen – and adding sufficient solar to cover its energy use.

An ADU Solar Advantage

Another significant potential savings with constructing a stand-alone ADU is a second chance to install solar on the main property.  If the original home does not have a good solar orientation, it may be possible to orient and design an ADU with enough solar for both the original home and the ADU. Any ADU-related shed or garage can be designed to optimize solar exposure. Large roof overhangs to shade the southern or western sun to avoid overheating can also expand the solar area. Or depending on orientation, sufficient solar can be installed on the main home to supply both the main house and the ADU – or some panels can be installed on the sunniest areas of each roof. In any case, optimizing the number of solar panels will lower the cost of ownership and renting.

Small ADUs can Live Large

The key to a successful small ADU is designing it for large living.  Building inexpensive non-conditioned storage spaces outside of the conditioned ADU, either in an attached or stand-alone shed or added to a connected or stand-alone garage, is affordable and leaves room for ample storage outside and living inside.  Smart kitchen/dining areas design can provide all the amenities in a small space. Creating accessible storage spaces under stairs and over cupboards optimizes the use of space, as do multipurpose rooms like office-bedroom spaces.

Our Experience

We decided to add ADUs to our two small rental homes on two different properties in Bend, Oregon, where the city changed the code to allow ADUs. We conducted energy modeling to determine the least-cost path to zero. We sealed the building envelope using Aerobarrier and insulated it well.  We used a small heat pump mini split for HVAC and a small heat pump water heater, used one Panasonic Whisper Quiet ERV in the bath and one in the kitchen, and installed energy-efficient electric appliances, including an induction stove. We added generous unconditioned storage areas outside of each unit. Because neither of the existing small homes had a good solar orientation and the ADUs did, we added enough solar on each of the ADUs to power both the ADU and the original house on each lot. So they both became zero energy homes.

Perfect for Low Income Housing

We can profit from rents while the tenants enjoy no energy bills. We have rented out two units, with two more on the way, to people with low incomes, referred by local non-profit organizations, providing them with affordable small, well-designed living spaces with no energy bills.

By Joe Emerson

Joe is the founder of the Zero Energy Project

Reference