JOHN MUIR, NATURALIST, wilderness preservation advocate and San Francisco-based Sierra Club founder once wrote, “Everybody needs beauty…to play in, where nature may heal and give strength to body and soul.”
Brazil-born architect Michael Rantilla’s residence in the woods in Raleigh, NC, echoes Muir’s sentiment. The home, which Rantilla calls his southern treehouse, is a unique 2,500-square foot (232-m2) structure on a 3/4 –acre (0.3-hectare) site designed to respect the delicate ecosystems that flourish around it. Rantilla takes pride in the fact that very few trees were uprooted to build the home. “One of my notions was to touch the land as lightly as possible,” he says. “The idea of nature infiltrating the house has come to pass and I’m thrilled.”
TAKING CUES FROM NATURE
Work on the site took 11 months and was completed in September 2008. Already nature has exhibited its hospitality. Rantilla and his fiancée moved in last October, and since have noticed the forest floor underneath the house. Deer freely roam close to the house and bird nests can be found all over. “A steel
I-beam is the perfect nesting area for birds,” Rantilla reports.
Rantilla selected natural building materials such as zinc and wood, and also used aluminum, steel, concrete and glass. A 40-foot (12-m) tall, 18-inch (457-mm) thick concrete shear wall serves as the spine of the home and a steel structural frame juts out from the concrete spine, creating the structure of the home’s aesthetic. The front porch, interior stairs and railings throughout the home are aluminum, and the large folded countertop in the kitchen is stainless steel.
“THE ENTIRE HOUSE ISN’T MADE OF METAL, BUT THE COMPONENTS THAT ENDED UP BEING METAL WEE CHOSEN FOR THEIR ABILITY TO BE ECONOMICAL AND ACHIEVE EITHER THE RIGHT STRUCTURAL PERFORMANCE OR SOME SORT OF ARCHITECTURAL CRITERIA.” -MICHAEL RANTILLA
“Steel is flexible and efficient. The house has some pretty large cantilevers, and steel is the material that lets you do that,” says Rantilla. “The entire house isn’t made of metal, but the components that ended up being metal were chosen for their ability to be economical and achieve either the right structural performance or some sort of architectural criteria.”
Like the trees surrounding it, the house springs upward from the ground and the materials used on each of the three levels were varied to reflect the ever-changing environment. Each floor level is a discrete rectangular volume clad in a different material and spun dramatically in different directions; this design structure resulted in several outdoor spaces where inhabitants can commune with nature. The lowest level spills onto a large teak deck beneath the house and a stepped concrete pyramid, which also supports the deck, meets the forest floor. Rantilla chose to construct the lower level out of zinc to blend with the forest.
He wanted the heartier materials closes to the ground and the more delicate design elements closer to the sky. Fully cantilevered stair treads project from the concrete spine and shift from aluminum to wood, such as maple and Brazilian ipe. The various materials echo different sounds and allow views and light to pass through.
LIKE THE TREES SURROUNDING IT, THE HOUSE SPRINGS UPWARD FROM THE GROUND AND THE MATERILAS USED ON EACH OF THE THREE LEVELS WERE VARIED TO REFLECT THE EVER-CHANGING ENVIORNMENT.
“I created an ascending lightness of materials as you move up the building,” says Rantilla. “The lower floors have richer, darker materials, and the aluminum at the top works well to reflect the variation in the sky.”
Intended as a natural sanctuary, the street-facing side of the house has few openings and creates a private interior. The house’s only connection to the main road is a 60-foot (18-m) long driveway elevated off the ground on concrete and steel columns. By contrast, the back of the home faces the woods and is all glass to make residents feel they are nearly outside and to take advantage of the northern light. Northern light in a hot climate like North Carolina’s is desirable because it is indirect and does not contribute to heat gain in the house. The height if the mostly transparent upper level of the home evokes a forest canopy-hence Rantilla’s treehouse reference. Exposed white metal deck ceilings allow natural daylight to illuminate the house and amplify the sound of rainfall.
“I purposely didn’t paint the aluminum and zinc because these materials have their own intrinsic beauty-they patina and change. The ipe will weather and turn from a reddish brown to gray,” says Rantilla. “I like that the environment will put its fingerprint on the house over time.”
Part if Rantilla’s plan of bring the outdoors inside was to make renewable, energy-efficient design choices. The home’s solar orientation was intended to keep the house passively hot and cool and illuminate the interior with as much natural light as possible. Other sustainable design principles include water-efficient landscaping, high R-value rigid insulation, high-albedo white TPO roofing, a high-efficiency heat pump, tankless hot water heaters, use of recycled materials and construction-waste recycling.
ONE MAN SHOW
The home reflects the challenges and rewards of the site. Located between zoning setbacks on a limited site, a stream buffer and a steep slope, the vertical, 3-story design was conceived as a solution. “I knew I wanted a dramatic site, or a topographic site with changes in grade, with a stream and a forest,” says Rantilla. “An overlay challenge was finding a site like that without other restrictions that prevent Modernist homes from getting built.”
Rantilla searched for the ideal site for three years, but he didn’t let the extended search deter his ambitions. When he saw the lot, he didn’t see the aforementioned obstacles; rather, he was inspired. He didn’t sketch a single design for his dream home prior to finding the right site, but when he finally found it, he seized the moment and completed the design in just three months. “The house is custom designed to that particular piece of land,” he says. “It was like a hand in a glove.
Eager to experiment with the practices and techniques he had learned in his full-time job as a commercial architect for the Freelon Group in Raleigh and looking to acquire new skills, Rantilla served as the architect and general contractor on his home. Armed with some knowledge of contracting from smaller projects, he was able to side-step getting a contractor’s license because he was building his own home. It was a process of learning how to roll with the punches on little sleep; Rantilla would visit the building site before and after work and on weekends when he wasn’t traveling for his day job.
“As an architect, you’re out there in the field helping with issues that come up and you administer the design alongside the contractors,’ says Rantilla. “But the general contractor is the guy who lives out in the trailer, hires the subcontractors and makes minute decisions, such as which screws to use or how to cut the material precisely. There was a steep learning curve; I had to learn how to deal with subcontractors, permitting, weather, inspections and so on.”
Just as Rantilla described metal as being a vital material for its flexibility, the take-away message for him was to learn how to yield. “I learned a lot about flexibility in dealing with unexpected circumstances, such as those that come from weather or from the unavailability of a material,” he says. “You adapt, think on your feet and look for the other solutions to a problem.”
The complications were worth it. Bending design to suit nature proved successful. Rantills already is talking about building his next home; in a few years, he may search for a coastal location, where a host of new challenges await.
There are no comments on this article.