The project transforms shipping containers into four two-bedroom single-family homes. Each unit benefits from large windows and private outdoor spaces. Squirrel Park builds on a number of previous AHMM modular construction projects, including MoMo, Raines Court and OKSea. These past investigations led to the conclusion that recycled containers were best for the volumes required.

MoMo
Mobile Modular (MoMo) is a research project, initially commissioned by the Peabody Trust, for a relocatable system of mass housing constructed from specially fabricated shipping containers. This type of system allows flats to be erected speedily on short-life sites and to be demounted and re-assembled in different configurations on other sites in the future. The idea of adopting the imagery of established temporary dwelling types is to explore the requirements of temporary housing beyond the immediate needs for shelter. The primary aim of these modular dwellings is, however temporary the housing, that the units are designed to support and engender a notion of ‘home’.

Raines Court
Raines Court is the result of an extended experiment into the potential for delivering high-quality housing through off-site construction methods. Three separate blocks – linked by a central circulation core – are arranged in a ‘T’ formation to address a road, a railway and a private landscaped courtyard. 42 one and two-bed apartments sit atop eight live-work units, while a perpendicular wing containing 11 three-bed family flats nestles behind. All flats are configured from the same prefabricated module, sized at the maximum allowable dimensions that can be transported on a non-escorted conventional truck.

OKSea
OKSea is a mixed-use regeneration project that activates an underutilised plot of land in downtown Oklahoma City. This urban site is transformed from a unused lot into a collection of 17 stripped and refitted shipping containers, hosting a corn dog restaurant, doughnut store, juice bar, and office spaces. Arranged in an angled formation across the site, the rectilinear volumes of the containers are offset and cantilevered to create a range of amenity spaces; private terraces at second floor, and a new public patio that augments the underutilized plaza to the east. A variety of apertures are cut into the boxes to ensure naturally lit and comfortable spaces inside the structure, which rises up to a double-height projection that addresses the street. The building is complemented by a robust, urban landscaping scheme that repurposes industrial liquid shipping containers as enclosures, planters, and light features.

PROJECT DESCRIPTION
Responding in a sensitive and sustainable way to Oklahoma City’s imperative to increase density in central residential neighborhoods, Squirrel Park makes innovative use of shipping containers to create four two-bedroom single-family homes on a single lot.

The design reinterprets the components of a traditional neighborhood street on a smaller scale, encouraging outdoor living and human interaction through covered front-facing porches and shared communal spaces. The site is developed as a park-like environment with the provision of a central gathering space featuring benches and a large fountain which is further enhanced through retention of existing mature trees and new planting to promote biodiversity.

The conventional interior layout contrasts with the modern, industrial exterior aesthetic of repurposed shipping containers. The mirrored strips on the containers’ white-painted exterior reflect the sky and surrounding greenery, helping to create a dematerialised mass. The units’ windows and site orientation are carefully controlled to provide privacy where needed as well as an ‘eyes on the street’ approach to site safety.

SITE
The site is located at the transition between the typical residential fabric along 32nd Street and the commercial corridor along Classen Boulevard. A single shared entrance and carport buffer the commercial property to the west while reinforcing the idea of a residential community. The immediate topography is extremely flat and low-lying. With no below-grade storm drain in the public way, site drainage was an issue and major driver to the design. The decision to raise the units off the ground using sono-tube pile footings minimised site disturbance and maximised the permeability of the site.

The unique nature of the site - a 27,000 square foot park-like atmosphere with extensive existing mature trees - is enhanced by locating the units on the site to retain nearly every tree and respect surrounding residences.

The project is designed to encourage outdoor living and communal interaction amongst residents. In addition to the central gathering space, front facing porch swings and ample covered outdoor space provide areas to relax and socialise with one’s neighbours.

DESIGN CONCEPT
Squirrel Park represents a unique collaboration between the architect and a client who is not a professional developer but is both user and owner/operator. The client wanted to create a development of small homes in which he and others could live with a strong community focus but also enjoy a degree of privacy. Thus began a close collaboration which required rezoning a single-family residential lot to allow four single family residences on the site.

The owner, who runs a local restaurant where the staff is made up largely of individuals who have been incarcerated, believes in second chances as ”it is a way of giving back to the community”. This became a guiding principle in the design. The goal was to take a vacant site that had been a magnet for crime and transform it, using sustainable materials, to create high-quality efficient residences that could be rented at competitive market rates.

DESIGN CONCEPT

The design employs 16 reused modular steel shipping containers set above the ground on piles to preserve natural drainage patterns of the site. The upper-floor units are shifted to cantilever 10 feet above the lower floor units creating a covered front porch as well as an upper level deck off the master bedroom.

The project responds to Oklahoma’s extreme climate, known for tornadoes, intense sun and heat. Not only are the containers reinforced with additional tube steel, but the lifting hubs are also fully welded to imbed plates in the footings. The resulting structure surpasses local residential building code tie-down requirements. Inside, metal stud framing is set 1 inch off of the steel shell and encased in 5 inches of closed-cell spray foam insulation, further isolating the interior environment. The extremely tight exterior envelope and high degree of insulation allow a significant reduction in tons of cooling when compared to a conventional wood framed single family home. An 8-person below-grade tornado shelter is incorporated into the site design.

SUSTAINABILITY & PERFORMANCE

The units are constructed out of durable corrugated steel shells, designed to withstand heavy loads in shipping and intended for the harsh marine environment. Openings are reinforced with additional steel and all joints are fully welded to maintain a waterproof assembly. The containers are also superinsulated with closed cell insulations and all internal materials were selected through the AHMM healthy materials toolkit.

Since the Oklahoma climate is substantially cooling-driven, the white color helps reduce heat gain and the use of mirrored reflective metal strips substantially improves solar reflection thereby reducing energy use. Every room includes large operable windows strategically located to encourage cross-ventilation and passive cooling.

The site’s micro-climate was studied and enhanced by siting the buildings and locating windows with good solar orientation and shading of the buildings. The shared gathering area is sheltered from the prevailing wind and shaded, while the fountain provides a cooling effect and calming noise. The environmental performance of the project is enhanced on many levels, both actively and passively.

• The project reduces its carbon footprint by using repurposing shipping containers and concrete horse troughs for planters, as well as minimizing the use of concrete slabs and footings.
• The new homes were arranged to allow retention of existing mature trees on the site. The use of lightweight shipping containers on concrete sonotube footings raises the units off the ground to avoid extensive foundations damaging existing root systems.
• New planting comprises native, climate resilient species and includes 10 new trees.
• The site is too low to connect to the main storm drainage system therefore storm and rain water run-off is provided by on site attenuation in soft landscaping and rain gardens.
• Drainage throughout the parking and pedestrian areas is diverted to heavily planted beds to increase the absorption rate.
• Multi-zone 20 SEER heat pump HVAC systems reduce energy costs and allow the user maximum control. Dedicated fresh air intake is incorporated to improve indoor air quality.
• The first floor and each upstairs bedroom are on separate thermostats to reduce heating and cooling demand when these areas are not in use.
• Separate mini-split units are incorporated into millwork in each upstairs bedroom.
• Condensers with variable speed compressors run at minimum speed required for demand.
• LED lighting is used throughout the units and the site uses low-voltage LED landscape lighting.
• All appliances are U.S. Energy Star certified.
• The carport is designed for future solar panels to be incorporated that will power the fountain and common area lighting.
• The units were designed with vegetated roofs, incorporating a planter tray system of native grasses. Due to budget constraints, installation of these has been put on hold.