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Modern Green Barn House

Hamptons house was completed with great green goals

Ma Green Scene Sept17 1
The Long Island Potato Barn is built from a concrete block. It’s a commercial form of a root cellar where a potato harvest was stored until the potatoes were purchased and distributed. Typically constructed at grade level, the potato barn was bermed up on both sides so that the ground would naturally keep the interior cool and protect the interior from freezing in the winter. The walls required pilaster, vertical columns of concrete to reinforce the walls and resist the lateral forces created by the soil against the outside of the building. Potato barn roofs are moderate pitched to allow both air movement and storage inside.

Architect Richard Stott, AIA, LEED AP, Stott Architecture, Southampton, N.Y., used this style as the inspiration for a new energy-efficient spec house in Sagaponack, N.Y., and by combining this approach with many sustainable goals, received six third-party ratings. They include: LEED for Homes (Silver), National Green Building Standard (Platinum), Energy Star, Department of Energy (DOE) Challenge Home, Indoor Air Plus and Water Sense certificates. The house’s structural engineer was Structural Visions Inc., Raleigh, N.C.

“Every one of my projects gets a very serious focus on sustainable and green efforts,” Stott says. “I believe buildings should be designed with the following attributes: quality, functionality, sustainability and delight. With these things come the Vitruvian concepts of firmness, commodity and delight, arguably not the only concerns for a building, even in the 1600s, but some of the most important ones that make architecture sing.”

Stott says he conceived this building “to be a logical answer to the conspicuous over-developed McMansions of the Hamptons scene.” It is large for a home, but, “Not large for a Hamptons second home on a luxury level,” he says. “As a spec house, it was an attempt to catch the attention of a moreconcerned, more-educated and more-sophisticated market.”

INDOOR-OUTDOOR CONNECTION

Instead of facing the front of the house toward the street, the house was designed and oriented to fit the sun’s arc through the sky. Doing this makes the best use of its warming rays in the winter and shields the interior from overheating in summer. In addition to the north/south orientation of the long axis of the building, its overhangs are sized so that sun penetrates the windows all the way to the north wall in winter, but shades the large expanses of south-facing glass doors in the summer. “Like the potato barns, the finished space at the lower level help insulate the building and make it perform better,” Stott says. “The pilasters expressed in this design are not structural, but do house the invisible leaders that shed water from the built-in gutters. They also serve as lanterns as they contain LED lighting, which is evenly distributed by translucent polycarbonate on the inside surface of each pilaster. In a few cases, the pilasters hide structural steel columns that hold up second- and third-floor balconies and decks. The pilaster lights are dimmable and remotely controlled.”

Kalwall, Manchester, N.H., supplied the translucent gable end walls and translucent ridge skylights. Since almost all south-facing glass is in the form of 8-foot-high accordion doors that fold out of the way when opened, it is vitally important to the house’s design that they be as thermally efficient as possible and have the correct solar heat gain coefficient to allow the winter sun to penetrate and be absorbed by the tile floor. “To me, the drama of true architecture is realized by expressing daylight and volume,” Stott says. “The Kalwall gable ends allow daylight to pass to the interior and interior light to escape in a soft glow at night. The Kalwall panels achieve an R-value of 11, almost the same as the old code once adhered to. In addition, they are constructed very tightly. In fact, we achieved a blower door test rating of about two air changes per hour, very difficult to achieve for a 7,500-square-foot home with enormous volume-to-square foot ratio.”

Stott sees the earth as being a powerful force with strong healing properties. He believes its strength, its energy and its chi are observed and felt both in and around the lower level of this home. The below-grade courtyard and terrace, allow a good portion of the interior living space to be comfortable and exciting in what would otherwise be a basement. “The daylight that enters the courtyard in the winter is reflected into the depths of the darkest corners and shades those same spaces from harsh direct sunlight in the summer,” Stott says. “The court, in the southwest corner of the assembly, allows the prevailing breeze to circulate in the outside space and flow through the house when it’s opened up.”

METAL USAGE

Prefabricated/preinsulated panels made of high-compression strength precast concrete with integrated metal studs from Superior Walls, New Holland, Pa., used on the basement foundation made it possible to install the walls in freezing temperatures. They added a level of insulation that would have been very difficult using a conventional concrete foundation. The studs are not structural, but allow easy installation of utilities, additional batt insulation, sheet rock or other wall finishes. The wall panels provided instant R-value of 21, which was increased to R-35 value with batt insulation.

The house’s envelope is constructed of 8-inch Magnesium-Oxide Structural Insulated Panels (SIPs) from Oceansafe Inc., New Orleans, that provide an Rvalue over 40. “They make it possible to simply stucco the outside, and tape and spackle the inside with no further labor or preparation,” Stott says. "The Mag' walls offer a much better fire rating and are not susceptible to mold growth like common [drywall] products are. This obviously saves time and money, but is also more sustainable from an energy and material use, sourcing and recycling standpoint. The Mag walls reduced labor because we can leave the interior side of the SIPs alone and simply paint them without further prep or labor. That’s all we had to do.”

The roof structure is made of 10-inch SIPs from Oceansafe to give an R-45 value, but uses a metal skin, instead of Magnesium Oxide. “The metal skin SIPs roof was was chosen for both esthetics and for ease of construction,” Stott says. “The standing seam metal roof attachment clips were attached to the metal skin of the SIPS panels requiring a little additional labor.” Stott says these three metal components—in addition to structural posts and one steel flitch girder—made a major impact on the aesthetics, the economy of construction, and life safety and durability of this building.

KEY CONTRIBUTORS

John Barrows, president of P3 Builder Group, Bridgehampton, N.Y., was the general contractor, and also helped with the design and specifications of the building envelope. Because Stott used SIPs along with the pre-cast insulated concrete foundation systems, “We were able to show that the combination of building systems has a better cost-to-benefit ratio than conventional stick-build with cavity insulation. But, as with any new system, the discovered efficiencies can lead to new less-conventional construction practices and scheduling. The SIP system of foam core and structural sheathing meant that wiring needs had to be thought out prior to installation. It can be done either within the panel during installation or placing outlets in a base molding chase or in the floor. Any of the three methods require an advance, thought-out plan that is different from conventional construction.”

Karla Butterfield, senior sustainability consultant, Steven Winter Associates Inc., Norwalk, Conn., provided rating services and energy modeling, and gave feedback on the building envelope and mechanical systems. “We performed inspections during construction to verify insulation installation, air sealing, and HVAC was being installed in accordance with the plans and specifications,” she says. “We used a blower door set up to test air infiltration prior to finishes being installed so the builder could identify where more air sealing needed to happen. And we final tested prior to occupancy for air infiltration, duct leakage, ventilation rates, and confirmed all materials, finishes and appliances were installed in accordance with specs.”