The angular Tulsa Loft stands out in its traditional neighborhood not just because it is contemporary, but because it is green. Bright green. The two 1,806-square-foot attached homes, recently certified LEED-Platinum, were designed by Tulsa, Okla., architect Shelby Navarro, AIA, principal at ONE Architecture, who grew up in his grandfather’s solar-paneled house. He and a business partner, builder Micky Payne, developed the building as a duplex with detached garages. “Everyone thinks of the sustainable-building trend as belonging to the coasts and eventually soaking into the Midwest,” Navarro says. “I thought if people could see all of these green features in one house, they would understand that building this way is not weird or difficult.” For this spec infill project, Navarro chose a neighborhood within a quarter-mile walk of a shopping district and a block from the bike trail system. (The lot’s existing house was given away and moved to a different part of town.) During construction, he hosted several open houses, and the 800 or so folks who filed through could see first-hand how technologies such as a geothermal heat pump and structural insulated panels (SIPs) work. “The one big feature people love most is the buffalo-grass roof,” he says.
Although LEED certification was not the original goal, major points came from the project’s $18,000 geothermal system, green roof, proximity to public transit, and SIPs construction. Navarro worked with SIPs manufacturer USA SIPs so that the design would accommodate the 4-foot-wide modules, which were manufactured within 50 miles of Tulsa.
Durability guided the choice of exterior materials. Navarro wrapped the front façade in 2x6 Western red cedar boards, and the slightly curved side wall is covered by Corten steel, a bridge-making material whose rusted exterior protects the metal core and also lends a unique aesthetic touch. The rear of the house is skinned with integrally colored stucco from Sto that eliminates the need for paint touchups.
Inside, Navarro’s liberal use of visual tricks—such as open-tread stairs, a folding glass wall between the dining room and deck, and strategically placed skylights—scoop in daylight and make the house feel larger than it is. “The glass wall folds completely out of the way. If you have 45 people over, they can wander in and out, and it adds square footage that you aren’t heating and cooling year-round,” he points out.
Wood for the stairs and a few countertops came from a dismantled barn in Wisconsin, and some of the interior doors are made with agrifiber, an agricultural waste product.
Navarro approached the design as a study in contrasts: old and new, rough and smooth, manmade and natural. On the inside, stainless steel, terrazzo, and drywall collaborate with the 100-year-old barn wood. On the exterior, the cedar slats evoke a wooden rain barrel while the curved steel wall is a nod to the metal rings that hold it together.
Even the green roof mixes an old idea—the earth-sheltered house—with new technology. The multilayer system starts with a waterproof membrane, and on top of that, a root-resistant compound that prevents roots from penetrating the membrane. Next comes a drainage layer that wicks away moisture from the roof’s surface, and a filter layer that prevents soil from clogging the drainage system. Plantings are then imbedded into a lightweight, specially formulated soil mixture that rests on top of the filter layer.
The roof has a 30-year warranty, and the grass needs no mowing. In case of prolonged drought, water can be pumped to the roof from a 500-gallon cistern in the rear courtyard. Navarro hooked it up to a basic sump pump with a switch that sends the cistern water to a hose bib on the roof.
Will Tulsa embrace these ideas? “The reception has been great, but people see it as ahead of its time,” says Navarro, who spent about $1,000 for the LEED certification. “We took a bit of a hit to offer it at this price, but we want it to stay competitive.”
The asking price of $379,000, which includes the custom build-out of a 470-square-foot space atop the detached garage, is commensurate with other non-LEED contemporary townhomes in the area.
“The house has been a great identity piece for people to learn about green architecture,” says listing agent Frank Petrouskie, sales associate for McGraw Realtors. “They’re not used to seeing a grass roof and geothermal. But the interest we’ve gotten tells us that people want to educate themselves.”
Cheryl Weber is a freelance writer in Lancaster, Pa.
PROFILE:Shelby Navarro, AIA, LEED AP
Sustainability is second nature to architect Shelby Navarro. Growing up in Verdigris, Okla., in a house equipped with solar panels, he spent time with his grandfather picking up trash for recycling and eating from the farm they tended. He took those values to architecture school at Oklahoma State University, where he experimented with designs that incorporated solar and wind power and rainwater collection. In 2002, Navarro founded ONE Architecture (as in “one can make a difference”), which specializes in eco-friendly residential and commercial projects. Although green-thinking contractors can be hard to find in Tulsa, on this project Navarro worked with like-minded builder Micky Payne. “He or I was out there every day, working through the issues that arose,” Navarro says. “I bought a lot of the low-VOC finishes and brought them to the site because the subs don’t necessarily get what’s speced.”
The SIPs company’s on-site training program helped the pair master the framing system, and they also rolled out the sod roof. Though still a niche, green building is gaining momentum there. “Once builders use alternative materials like SIPs, they end up doing it more often because it’s quicker and easier than conventional framing,” Navarro says. “And the ones who learn how to handle the newer techniques are in pretty good demand. It opens up a market for them.”
Flooring Rapidly renewable bamboo from CFS Corp. is used in the main living areas and an upstairs hallway. Navarro chose the pre-stained burnt mocha color for its rich, dark hue and because its binders are formaldehyde-free. 866.751.4893. www.premiumgreenbamboo.com.
Zen Garden and Shoe Rack
Navarro saw empty space under the front stair as an opportunity for self-expression. The Zen garden can be repurposed as a koi pond, fountain, planting bed, or sculpture garden. Shoes can be stowed neatly under the landing, preventing contaminants from being tracked indoors.
Toilets Each bath is furnished with an Aquia dual-flush toilet by Toto. The two-piece unit operates at 1.6 and 0.9 gallons per flush and comes with a push-button flush option and a soft-close seat upgrade. 888.295.8134. www.toto.com.
Eco-Terr recycled-glass terrazzo floors from Coverings Etc. are made with 70% recycled content. 305.757.6000. www.coveringsetc.com.
Green Roof A ship’s ladder leads to the deck and buffalo-grass roof, where Navarro installed the Garland GreenShield layered roof system. At its base is a multi-ply, modified bitumen waterproofing membrane. Specially engineered layers on top prevent roots from penetrating the membrane, draw moisture away from the roof’s surface, and keep soil from clogging the drainage system. 800.321.9336. www.garlandco.com.
SIPs and Rainscreen The 5 5/8-inch SIPs that make up the walls have an R-factor of 26 at 25 degrees F, according to USA SIPs. Between the SIPs and the cedar and Corten steel cladding materials is a rainscreen system from VaproShield of two breathable, waterproof membranes and brackets that hold the exterior materials away from the walls. USA SIPs: 800.835.3434. www.usa-sips.com. Circle 374. VaproShield: 866.731.7663. www.vaproshield.com.
The twin houses share a wall filled with Fiberlite blown-in cellulose. The 80%-plus recycled-newsprint cellulose makes an excellent sound barrier and also insulates the ceiling cavity under the green roof. 800.641.4296. www.fiberlitetech.com.
Carpet Squares Floors in the two bedrooms are covered in Shaw nylon carpet squares made from 27% post-industrial recycled content. The 2-foot modules, which carry the Green Label Plus certification from the Carpet & Rug Institute, are easy to replace and can be returned to the company for recycling at the end of their life. 800.441.7429. www.shawfloors.com.
Lighting Navarro used compact fluorescent recessed lights throughout the living area but speced longer-lasting LED bulbs for the taller ceiling, where they are harder to replace. The Cree LED lights—LLF LR6 12-watt can inserts in standard insulation-contact (IC) cans—have a 25-year life span and produce less heat than compact fluorescent, incandescent, and halogen bulbs. 919.991.0700. www.creells.com.
Raised wood counters were reclaimed from a 100-year-old barn. Work-height countertops are Squawk Mountain Stone, hand-cast from recycled paper, recycled glass, coal fly ash, and cement. The material is finished with Jamo’s water-based, low-VOC Stone Specific sealer. Squawk Mountain Stone: 425.486.3417. www.tmi-online.com. Circle 378. Jamo: 800.826.6852. www.jamoinc.com.
Tankless Water Heater The gas-fired T-K3 water heater is 80%-plus efficient, according to Takagi. It activates at 0.5 gpm, which allows for the use of low-flow fixtures in the bath, and can be converted to a direct-vent model. 888.882.5244. www.takagi.com.