We’ve said this before: single-family homes in sprawling suburbs are the least efficient, most wasteful housing type. There are many incremental, subtle ways to gradually increase density in our neighborhoods, house more people, and keep development at a human scale. Here are three:

Duplex

Even though this housing type is fairly common in the U.S., it is still surprisingly effective. Simply by adding another unit under the same roof, the capacity is doubled.

The duplex prototype we developed is a simple rectangular shape in plan and two floors that maximize the small footprint. The two units are mirrored along the demising wall. A familiar gable profile helps this prototype fit in a single-family neighborhood.

The design includes a “flex space”, which can be used as a library, office, hobby or study room or even function as an additional sleeping area. With consideration for affordability and optimum use of space, we stacked the bathrooms and organized a single “wet wall” at the separation line between the two duplex units.

One of the main features we built in is flexibility. The design presented here is but one configuration of a flexible building module. We envision the form being highly configurable and adaptable for a variety of uses:

live-work unit configurations with top-floor living areas and ground-floor lobby, office, or workshop areas;
community uses, such as combined senior and child care;
accessible, senior-friendly ground floor units.

2. Small Multifamily Infill

Urban infill often means working with leftover space between adjacent developments or optimizing a lot for a more appropriate function than the existing one. In most cases, one has to deal with a narrow and deep site.

“Splash” is our 7-unit multifamily prototype developed for a standard San Francisco lot. This innovative housing typology harmoniously fits into the urban context while adding 7 new units with access to both shared and private outdoor spaces, and ample bike and stroller parking. While modest in size, Splash offers the next logical step to organically grow the neighborhoods within the context of existing construction.

In contrast to the 3-bedroom units common in low-rise residential neighborhoods, Splash offers a mix of (5) studios, (1) 2-bedroom, and (1) 4-bedroom units, supporting variety in the demographics of its tenants and responding to the different seasons of their lives. Some of the tenants we envision can be young professionals, teachers, workers, small families, and extended families looking for a more reasonably priced housing solution.

Our approach to keeping construction and operating costs down is to reduce the size of the units, while elevating their quality with a thoughtful layout. Passive House methods, such as solar screens on the east and west, super-insulated airtight envelope, narrow footprint for daylighting, and efficient mini-split systems can keep utility bills low for the tenants.

Socioeconomically, Splash can accommodate different tenant types and adapt to changes in demographics. For example, seniors who are downsizing will love the accessible ground floor units, young adults will enjoy the upper studios, and families who appreciate quality in a smaller footprint will love the 2-4 bedrooms.

3. Modular Multifamily

Like a tree growing tall and wide year by year, our housing prototype begins with only one unit that can be stacked, mirrored and rotated. A typical Tree House module fits on a standard single-family lot and is composed of 3 units stacked vertically and a ground floor garage/storage space that can be easily converted to cafes and other mixed uses to fit the site.

While the preference in site planning is given to pedestrian-friendly concepts and connection to public transit, our project recognizes the practical merits of owning a car, especially in developing city neighborhoods. The ground floor can be configured to provide garage space initially and later be converted into a variety of commercial and community uses.

We paid special attention to the connection between the indoor and outdoor environments, so often missing in urban housing. In addition to the generous street landscaping and “courtyard” parks, each module has an option for an open terrace with an integrated planter. As the tenant’s needs change, this space can be converted into a bedroom or home office.

A single professional or a young couple will appreciate the built-in flexiblity to expand the living areas as the family grows. An active senior will enjoy meeting her friend in the coffee shop downstairs to discuss the book they both bought in the bookstore nearby. A parent working from home will enjoy the convenience of the child care located within the “building bundle”, along with the playground and picnic areas behind the street-facing facade.

These are just three of many types of housing in the twilight zone between the traditional single-family home and residential towers. All of them are flexible in how they are occupied and allow a gradual increase in density. All of them work best in walkable, transit-oriented communities. We hope that our prototypes will inspire others to take things into their own hands and break away from traditional home development towards smart growth.