Sustained Haus: An ADU Designed to Be Built, Again and Again
Project Stories
For Newton's ADU Design Challenge, we refined our jury-honored Sustained Living prototype into Sustained Haus: a 900-square-foot, two-bedroom detached ADU designed to be permitted with clarity, built with confidence, and repeated across Massachusetts neighborhoods.
Massachusetts has made the accessory dwelling unit a by-right use. Newton is now asking the harder question: what should these homes look like, and how does a homeowner get one built without losing a year to uncertainty?
Newton has allowed ADUs since 1987, yet the city has averaged roughly ten new ADUs a year since 2014, and most have been internal conversions, according to reporting by the Newton Beacon. Residents describe the same obstacles we hear from homeowners across the Commonwealth: no clear place to start, zoning questions that surface late, and site costs (utilities, drainage, fire protection) that no one flagged early. Newton's response is a design challenge that invites architects to propose ADUs residents can help select, with the goal of offering pre-approved plans that shorten the path to construction.
We think that's exactly the right question. Our answer is Sustained Haus.
A model, not a one-off
Sustained Haus builds on our Sustained Living ADU, which earned a Jury Honor (Notable Standard ADU) in the 2026 Massachusetts ADU Design Challenge. For Newton, we developed it into a complete package. Beyond renderings, it includes the drawings a builder actually needs.
At a glance
Type: Detached ADU, by-right protected use
Gross floor area: 900 SF
Program: Two bedrooms over two levels
Height: 29 ft
Window-to-wall ratio: 11.8%
Foundation: Concrete frost wall
Status: Proposed design, Newton ADU Design Challenge submission
The form is intentionally simple: a compact two-story volume under a single sloping roof, wrapped in dark vertical and horizontal cladding, with a wraparound deck, a second-floor balcony, and generous openings placed for daylight and passive solar gain. It reads as a contemporary New England outbuilding, at home behind a Victorian or a mid-century Cape.
For homeowners: a home that works as hard as you do
A 900-square-foot ADU has to do many jobs over its life. Sustained Haus is organized around flexible, multi-functional living spaces that can serve an aging parent, an adult child, a caregiver, or a long-term tenant, and adapt as a family's needs change.
Open first floor. Living, kitchen and laundry share one connected space with front and rear entries and direct access to the deck.
Private second floor. Two bedrooms and a bath sit above the daily activity, with a balcony off the upper level.
Lower operating costs by design. A highly insulated envelope, an integrated solar wall and a rooftop photovoltaic array on a standing-seam metal roof are designed to reduce energy costs and carbon footprint over the life of the building.
Built to last. Durable, regionally appropriate materials and a straightforward structural system support long-term resilience and reduce the need for premature repairs.
For contractors: fewer questions, cleaner bids
Builders price what they can see. Our package goes beyond floor plans and renderings to include:
First- and second-floor plans with dimensions
Elevations and building sections
Wall section, footing and foundation details
Foundation, first-floor, second-floor and roof framing plans
Life-safety plans for both levels
The structural grid is deliberately simple, and the design is set up for panelized or hybrid prefabrication. Wall assemblies can be factory-built to improve quality control, reduce waste and shorten time on site. That gives general contractors, framers and modular manufacturers a repeatable product rather than a custom puzzle on every lot.
Why process matters as much as design
A great ADU design can still stall at permitting. That's why every Flow project follows the same four steps:
Define. We document existing conditions, zoning, site constraints and risks before design begins, so the expensive surprises surface early.
Envision. We align the owner's goals, budget and context into a clear design direction.
Design. We test options against performance, feasibility and cost.
Document. We produce coordinated, code-compliant drawings that a building department can review and a contractor can build.
Behind that process is a team of architects and designers working from Salem, Massachusetts, and La Vega, Dominican Republic, led by an architect registered in Massachusetts, Maine, New Hampshire, Connecticut, New York and Florida. Flow Design Architects is a certified Minority Business Enterprise (MBE) in Massachusetts. ADUs, additions and residential renovations are the core of our practice. We know the codes, the inspectors and the realities of building on tight suburban lots.
Let's build more of them
ADUs are one of the most practical tools Massachusetts has to add housing gently, keep families close and give homeowners a long-term asset. They only work if they get built.
If you're a homeowner in Newton or anywhere in Massachusetts wondering what your lot can support, we can tell you. If you're a builder, framer or modular manufacturer who wants to deliver more ADUs with a reliable design partner, we'd like to hear from you.
Start a project or write to us at info@flow-design-studio.com.
— Flow Design Architects
Images are architectural visualizations of a proposed design. Sustained Haus is a design-challenge submission; any individual lot requires site-specific zoning, code and engineering review.
Project Team
Principal in Charge / Project Architect: Darguin Fortuna, AIA, NCARB, NOMA
Visualization: Flow Design Architects