Perched in the Oakland Hills overlooking San Francisco Bay sits Margarido House. Since its construction in 2008, the California home has received recognition for its advanced sustainability.
The guiding principle for the residence was to not only exist within a dynamic environment—but also to be a responsive part of it. Builder/developer and resident Mike McDonald centered the project on passive design, utilizing the surrounding climate to minimize energy use indoors.
Forgoing traditional air conditioning, McDonald’s team focused instead on efficient sunshades surrounding the house’s large windows.
They discovered that Bar Grating, a common industrial flooring item, could be elevated to provide an eco-friendly cooling system. A large overhang made from Aluminum Grating was installed around the southern and western sides of the house. Bolted to cantilever beams on the second level and extending 8 feet, the Grating filters harsh sun rays and keeps the first floor cool.
Being an outdoor application, Aluminum Grating was selected for its noncorrosive properties. Installer of the sunshades, Chris French Metal Inc. of Oakland, California, specified it to meet some essential criteria.
French, principal of the company, said, "We wanted a material that would last a long time, so we kept coming back to Aluminum. It’s weather resistant, lightweight, and sturdy enough to get us into the [weight load factor] safety zone."
Indeed, the metal’s high strength to weight ratio allows the overhang to serve another purpose. With the addition of a handrail on the west-facing sunshade, the Bar Grating functions underfoot and doubles as a balcony deck. On the southern side of the house, the Grating also serves as a catwalk for window maintenance.
In addition to preserving comfortable temperatures indoors, the Bar Grating plays another crucial role in the home’s eco-friendly design. Underneath the Margarido House, a 4,000-gallon concrete reservoir collects runoff as part of a rainwater recycling system. The versatile Bar Grating is a critical element in the success of this system.
Firstly, the overhang allows water to pass through to the ground, where it is directed to the driveway. There, Bar Grating is used again to cap off a trench where runoff flows into the reservoir. The trench Grating also provides access to components for the water recycling system, all while remaining durable enough for cars to park and drive over.
Lastly, Aluminum Grating Stair Treads were installed on the exterior of the Margarido House to provide access to a rooftop deck. These durable Treads increase safety, all while tying together the modern and airy appearance of the house.
The team at Onion Flats, Architects of the project, aimed to create "an experience of tranquility and lightness in this heavily grounded residence.” Helping to achieve this effect, McDonald stated that the open Grating “has this aviation and nautical feel to it."
With the Grating’s green benefits and other sustainable features, the finalized Margarido House is 55% more energy efficient than California’s Title 24 energy standards. Following its debut, it was named the first LEED-H Platinum custom home in Northern California. It’s also the first house in the nation to be both LEED-H certified and GreenPoint Rated.
When discussing the use of the metal Grating, McDonald said, “It evolved organically during the design build phase.”
Although his team may not have foreseen the impact of this eco-solution, the Aluminum wing has become an iconic feature of this exceptional home.