By far the most prominent feature of CHIP and the design driver for CHIP’s architecture has been its innovative insulated skin. Of all the materials that go into a building, insulation does the most to make that building perform its primary function: separating the inside from outside. Despite this, it is often the most invisible aspect of architecture. Its value is measured purely quantitatively with little thought as to how it will look since it is stuffed behind finish material. For architecture this is an important and overlooked problem.
Architecture’s primary function is to create shelter, or to distinguish something that is human made and separate from the natural world. From the perspective of modern building, this separation between inside and outside is something that can be measured in terms of comfort level (how well a building maintains a desirable environment for the occupant in relation to what it is outside). It is insulation that makes this possible and the more efficient the insulation is the better. Contemporary architecture advocates function and efficiency, but its most efficient component: insulation, is ironically the least expressive.
This year’s Solar Decathlon gave SCI-ARC and Caltech the opportunity to tackle this problem. Our design does more than emphasize the harvesting of solar energy. It expresses energy conservation as well. We made CHIP’s insulation expressive of its function as a barrier between exterior and interior. In the process, we were able to make the insulation even more efficient and effective in creating an architectural building envelope.
The obvious solution to making insulation a primary architectural element is putting it where it can be seen: on the outside of the building. It’s amazing how this one move eliminates a lot of problems with insulating a conventional building, and makes one wonders why it hasn’t been done before. For one, insulation isn’t confined to stay between the structural walls, so we can use more of it. Also, outside of the structural walls, it can be applied continuously. This eliminates thermal bridging, a condition that occurs in conventional framing where heat can pass through the non-insulated 2x4s in the walls. With no restrictions from the structural walls a 16” thick continuous layer of insulation wraps around the entire building giving it an R-value of 40 (a typical home in Southern California has an R-value of 13).
But after moving the insulation to the outside of the building, how does one treat it architecturally? To emphasize the building’s innovative insulation strategy we have wrapped the blanket in a single layer of architectural vinyl. This acts as an excellent water barrier and eliminates the need for roofing, siding, gutters, and flashing. More importantly, the vinyl does not hide the insulation like a rigid cladding strategy would. The vinyl expresses the function of insulation as a puffy blanket for the building.
Fabric such as vinyl isn’t new to architecture, but the way we use it on CHIP is. Fabric is most often found in tensile structures, like stadiums, and large airport terminals. The material has always been used in tension, meaning it has been pulled into shape over an existing structure. CHIP is unique in that it uses architectural fabric in compression. The vinyl is draped over the insulation and pushed into the structure of the house with bolts that also tie down the supportive net. This gives CHIP its signature look of a puffy bag wrapped in a net. Its unique appearance and material effect has connotations of upholstery, moon bounces, and space suits.
The loose tolerance of the insulation system allows it certain freedoms and limitations towards how it is incorporated within the architecture. The insulation works really well across solid volumetric shapes, even if they are not orthogonal like CHIP. It has the ability to soften these hard shapes making them more playful. However when it comes to the openings in the building something more needs to be done. While the puffy blanket can negotiate edges and corners of volumes with diagrammatic clarity, holes punched through the volume for windows and doors create problems that are not only technical, such as drainage, but also formal, such as a clear reading of the mass and openings.
As a contrast to CHIP’s soft and puffy volumetric shape we’ve developed a solution that allows this system to terminate around connections between the interior and exterior. These are the hard pieces of fenestration that protrude out from the doors and windows. We call these the collars of building in keeping with the morphological analogy to the space suit. Like a space suit that must cover and be flexible enough to accommodate a moving body, its collars must also be precise and calibrated to accept strong connections from incoming services. In the astronauts case these are valves for air supply, water, and secure connections to the helmet and gloves. In CHIP’s case the collars must accommodate doors, windows, air intake, exhaust, as well as the means for an occupant to pass through the envelope.
The contrast between the soft mass and hard collars give CHIP a reading of function and efficiency. Where the overall mass is large and simple an economical wrapper that allows for loose tolerances provides the insulation. Only in the few openings of the building where precision is needed are there hard collars. These frame the openings and give the vinyl skin a clearly defined boundary onto which it can terminate. Just as the skin emphasizes the puffy character of the insulation, calling attention to that which separates inside from outside, so do the collars. Anything that passes through the thick and soft envelope of CHIP must come through these access points. Not only does this give CHIP a clear functional reading, but it also makes a lot of practical sense in terms of the building organization. For one, it allows the vinyl membrane never to be penetrated, since anything entering or leaving the building does so outside the puffy vinyl boundary. All of our exhaust exits through the North end at the highest point of the house. The West collar serves as the brain of CHIP bringing together all of the electrical and mechanical control systems for easy accessibility. This also allows one to replace or upgrade components in the future without disturbing the vinyl membrane.
Through these two architectural systems: the puffy wrapper and the hard collars, CHIP is able to articulate a new reading of inside vs. outside. The insulated wrapper expresses the shelter created by the building envelope. The insulation is efficient from both a performative and formal perspective. The insulation provides both the function of insulating as well as the expression of insulating. This clarity in the reading of the building vs. the function of the building is significant for architecture in that the two are no longer separated from one another. The hard collars further this clarity by defining the zones which tie the exterior to the interior. So on the one hand the soft shell separates us from the environment and protects us, while the hard collars connect us to the environment. These two systems serve as means which the architecture communicates its primary function for us humans. Architecture both distinguishes us from the natural world and brings us closer to it by giving the world a meaning. By challenging the convention of building and the readings of architecture CHIP gives us a new way to look at shelters as something soft. This softness is a friendlier way us humans can distinguish ourselves from the world. CHIP does not fight the environment but has found comfort in it, and hopefully we can too.