The Dakota Mountain house in Dripping Springs combines passive environmental strategies and affordable construction with a co-living concept.
Architect Low Design Office
Client Robert and Rosalie Bollom
General Contractor Low Design Office
Structural Engineer Persyn Engineering
An architectural truffle hunt through the Hill Country west of Austin will reveal, tucked in among the weeds, a plethora of glistening goodies. These villas, many of which have appeared in the pages of this magazine, are sterling examples of upper-crust residential design — materially rich and finely detailed buildings in a variety of styles, everything from neo-Tuscan limestone piles to post-Miesian glass boxes — that take advantage of the landscape’s raw beauty and proximity to the mushrooming tech hub that is Austin. By and large these homes are highly designed retreats for their patrician residents that turn their backs on the problems of the urban-dweller in favor of blissful isolation in Arcadia — the sorts of places where most people would probably love to live, if they could afford to.
It’s much rarer to find a house in these parts that actively seeks to address some of architecture’s most pressing issues of the day: housing shortage, equity in design, climate change, and ecological depredation. It’s very rare anywhere, in fact, to find a house like the Dakota Mountain house, which is as much an essay in 21st-century architectural prudence as it is a place of dwelling.
The house was designed by Low Design Office (LOWDO), a collaborative practice headquartered in Austin and in Tema, Ghana, and run by co-founders Ryan Bollom, AIA, and DK Osseo-Asare. The pair met while studying for their master’s degrees at the Harvard GSD and based their studio on a simple premise: to do more with less. This ethos is on display in a city that LOWDO designed for eastern Nigeria, called Anam City, which combines urban density and technology with agricultural production zones to create an ecologically conducive environment in the resource-strapped region. It’s also exhibited in a series of houses the office has designed in Central Texas: Garden Street House in East Austin, which combines green building moves with an extrapolated framing system that defines areas on the interior; River House, on the floodplain of the Guadalupe River, which serves as a gathering spot for three siblings and their families, providing spaces for connection and retreat; and now, the Dakota Mountain house, which synthesizes LOWDO’s explorations in sustainability, co-living, and affordable construction.
All three of these projects deconstruct the local residential building vernacular and deploy it in ways that are more suited to living comfortably in predominantly hot Texas while relying less upon air conditioning than is currently the status quo. The key element is the roof. “In our East Austin house, and again in the Guadalupe River house, it was an experiment in how to create a roof that can protect from the sun and create outdoor living spaces,” Bollom says. The Dakota Mountain project builds on that idea with a double roof: An overarching canopy, framed with cedar timbers and topped by galvalume panels, shelters the long, rectilinear enclosure of the house, a wood-framed stucco box with a flat, thermoplastic polyolefin roof, as well as surrounding and interstitial outdoor living spaces, including a screened porch. The house is sited for ideal solar orientation, with narrow ends to the east and west, and long faces to the north and south. This siting also meshes well with the topography, which slopes down to the north, opening up sweeping Hill Country views that the house takes in with ample glazing on this facade. The prevailing breeze, which is almost constant, also comes from this direction and ventilates the space between the canopy and the house, where there is a covered roof deck.
The canopy roof form is a hybrid between a shed and a hip that has been sculpted to optimize rainwater collection — the building’s only source of water. It collects 3,300 gallons for every inch of rain via a 12-inch gutter on the south edge that feeds into a 33,000-gallon tank. According to Bollom, throughout the course of two summers of occupancy, the water level in the tank hasn’t dropped below 75 percent. The hipped planes of the roof slope down to cover the narrow eastern and western exposures with long overhangs that protect the house from low-angle sunlight while keeping the outdoor spaces they shelter more intimately scaled than if it were a standard shed. A gap near the middle of the canopy reduces the mass of the building and signals the two distinct but connected living spaces below.
Bollom, who grew up north of Houston, designed the house for his parents — a retired schoolteacher and a retired contractor who had a minimal budget to spend but ample trust in their architect son — and his sister and her family. The 3,230-sf interior space is divided between an 1,810-sf primary residence, a 920-sf secondary residence, and 500 sf of shared space.
“Co-living is something I’ve been interested in for some time,” says Bollom, who taught a studio on the subject at UT San Antonio. “How can we bring at least two family dwellings together that could operate separately but also be connected? There’s a lot to consider in this idea when thinking about housing for the future, as it gets more expensive and less available for the average person.”
The primary residence, where Bollom’s parents live, is on the west side of the building and connects with the secondary residence to the east via a large, shared pantry. Exposed pine joists articulate this connector-space and admit daylight from clerestory windows that ensure every room in the house is naturally lit. Each residence has its own entrance and car port, which is also covered by the canopy roof. Everything is on one level, with no steps anywhere, to ensure that it will continue to be a viable abode for its residents as they age. The long but relatively narrow volume of the house also promotes cross-ventilation. Bollom reports that it remains comfortable inside well into the summer months, long after the neighbors have turned on their air conditioners, and energy use records support this. The 2030 Challenge Zero Tool indicates that in its two years of occupancy, the house operated at a 72 percent reduction of the electricity compared to a similar sized house in this climate. “I’d say it’s performing very well,” Bollom says, “especially considering only passive design strategies are driving this.”
A sustainable house, indeed, but not an expensive house. Averaging out the cost of everything contained beneath the canopy roof, and adding a percentage for the labor and general contracting services Bollom donated to project, the price comes out to about $162 per sf. That figure is competitive with most local production homebuilders. Include a design fee, and it’s competitive with most custom homebuilders. But what the house offers as a piece of architecture and as a solution for the future of sustainable development is worth so much more.
Aaron Seward is editor of Texas Architect.