Responsible Design Today
By: Concrete Homes
Architect Richard Potestio, AIA, of Potestio Architect, tells an apocryphal story about some structural repairs that were undertaken at Cambridge University. A quantity of oak timber was needed to supply the necessary repairs. While considering the viability of procuring the required amount of lumber, the architects noted a great stand of mature oaks, several generations old, growing by the quad. The idea of cutting them down for the purpose of the repairs was initially unthinkable, until the architects realized that they were indeed planted for that very reason, to be harvested at about the time the old oak members would be in need of replacement.
If the story isn't true, it should be. It tells us a lot about Potestio's ideas regarding sustainability and stewardship--planning for the future through responsible design today.
To listen to Potestio speak of sustainable design is to gain a real appreciation of responsible architecture. Apparent is a sense of its urgency as resources become limited and the environment reaches critical mass: "Architecture must support habitation and lifestyles in harmony with the environment," he says. "Architecture must promote conservation, the wise use of land and materials, and ultimately be worthy of stewardship."
Potestio's concept of stewardship emanates from a notion of building for the future and taking ownership of one's environment. "Any building is a culmination of creative and physical energy," he says. "If a building attains a certain beauty and aesthetic resonance and transcends its original function for being, people become stewards of it. Those who are trendsetters do not understand values that transcend today's fashions. An architect's first responsibility is to think of the big picture: What will this community look like in a hundred years?"
A rare and dramatically conceived design that addresses these issues is Potestio's Ganz residence, located outside Portland, Oregon. The residence fulfills its author's vision of sustainable habitation and provides a lesson in using sustainable materials, like concrete masonry units, to achieve a structure truly integrated into its environment. That environment could not have been more challenging, or rewarding, in its final conception.
Rising 1,100 feet from the valley floor, the site occupies a hillside summit with views of the confluence of the Columbia and Willamette Rivers below and the Cascade Mountain Range beyond. Depending on your orientation within the house, there are views of Mount Hood, Mount Ranier, Mount St. Helens, and Mount Adams, as well as Sauvie Island and Vancouver Lake.
Since the Ganz residence was built in a sloping terrain, every advantage was made of a difficult site. Part of the house is earth-sheltered, being dug into the hill on its west side. Although motivated by practical necessity, the site created the opportunity for sustainable effects that blend aesthetics with a minimal amount of visible intrusion into the landscape.
According to Potestio, "It had to conform to rules that restrict its visibility from the wildlife refuge below. This required a low profile and materials and colors that blended with the earth and surrounding vegetation. The Ganz residence achieves this with a contour-hugging section and sloping roofs that follow the hillside."
Potestio loves the look of plain CMUs. He used the most basic gray block on both the interior and exterior exposed walls of the house. "Concrete block is my favorite material. I've used concrete block in almost every one of my projects." Among the advantages to using block that Potestio cites are the speed of construction ("block goes up very quickly"), the thermal insulating properties inherent in it, and the way it "can showcase the craft of the builder." Potestio continues: "Your handiwork is going to be noticed. I like materials that show the method of construction and the hand of the builder."
When combined with sustainable design concepts and other materials, concrete block can address structural needs, aesthetic concerns, and green building considerations to provide responsible construction that is ecologically sensitive as well as enduring. CMU acts as the lynchpin in sustainable architecture, tying together the integration of other materials with the landscape. Potestio appreciates the honest simplicity of CMUs in his designs: "I love the look of the most basic block. It offsets whatever materials we use. I appreciate the honesty of that material. Truly the most immediate material is the concrete and the masonry. Block is an ingenious material, so rudimentary yet so elegant and utilitarian."
The Ganz residence masonry contractor, George Rice of Rice Masonry, concurs, surprised at the total effect concrete masonry has on the home. "When it all came together, it was awesome," says Rice. "The effect was real simple; plain, clean lines. Potestio's job of bringing the outside environment in was terrific. Everyone was amazed."
In addition to Potestio, Rice also sees the wisdom of using sustainable materials like CMUs: "It is better for our industry for builders to use block, although it's hard in this part of the country. People prefer to use wood. Stick-frame is just more common, and that's the reason you don't see much block." According to Rice, the advantages of using CMUs are numerous. "The material will last longer than wood," he says. "There's virtually no maintenance in a house designed like the Ganz residence, and no painting on the exterior."
With a frame job, builders have to use some kind of siding. In this wet environment, by using CMUs with a proper sealant, you would not have the problems of mold and rot that you encounter with wood siding. "It's not uncommon," says Rice, "to have building failures because of water intrusion and rot. [Wood frame] buildings are being built too tight these days: They rot from the inside out."
Potestio's design does not visibly intrude on the natural beauty of the landscape. Rather, it is built into it. One approaches its unassuming entrance--simple, opposing geometric planes--rising from a low courtyard that backs up into the slope. A pergola and clerestory complete this elegant facade.
Walking into the Ganz residence, "one has the sense," says Potestio, "of entering a cellar, of entering the earth. One can only look up at the towering firs. This feeling of being so compressed is shattered the moment the door is opened. Opposite is a wall of glass at the edge of the hillside that reveals a panorama from the height of 1,100 feet. Precise placement of the door and windows in relationship to the trees outdoors enables a framing of Mount Hood that is breathtaking. The first suggestion of the site registered at the entry drive is finally satisfied. It seems as if you could reach out and touch the mountains."
The layout of the residence is simple and accessible. Communal living space--living area, dining room and kitchen--occupies the central core of the house, and bedrooms flank this section in opposite wings. Apart from a second-story study, all living area is confined to the first floor. There is ample glazing, especially along the home's middle core, allowing for light and the site's spectacular views.
Largely because of its profile and its use of CMUs as a non-reflective surface, the residence is practically invisible from the valley floor. Brian Marek of B.K. Marek Construction, general contractor of the residence, finds the site ideal for the realization of Potestio's vision. "The site was already set up for an earth-sheltered design," says Marek. "As you approach from the road, you encounter a natural berm with a beautiful view. Rick had the idea to lower the home to maximize the view. We dug the site out like a basement home. The center drops down along the slope. We had to be careful in our site preparation to create an earth shelter. There was some intricate excavation involved." Marek notes that waterproofing, rock fill and drainage pipe were necessary along the earth-sheltered portion of the house.
In addition to the use of plain CMUs for lower walls, the residence also features metal siding and a metal roof that create a monochromatic effect enhanced inside and out by accents of bronze, exposed timbers, black slate and other materials. An oversized floor-to-ceiling fireplace follows the gray monochromaticity realized in the contrasting textures of block and poured concrete hearth and mantel. In the great room, huge floor-to-ceiling windows are carefully oriented not only for views but also for light and prevailing breezes. Potestio considers the idea of sustainability to include considerations like window placement as contributing to the basic sustainable premise: "Is my design worthy of being preserved for future generations?"
The important lesson to learn from the Ganz residence is that sustainable architecture does not have to appear strictly utilitarian, but its beauty and the principles that contribute to its embodiment of responsible architecture also inhere in its designer's commitment to stewardship. The combination of CMUs and earth-sheltered design offers practical solutions to the enduring problems of insulation and the ability to maintain interior comfort.
The urgent necessity of putting to use materials that are readily available and that don't strain our fragile environment contributes to responsible design criteria. When we begin to think again of design in terms of legacy and what future generations will appreciate of our work and what uses they will create of them, we will have achieved this crucial pairing of sustainability and stewardship. It proves again the old tag, ars longa, vita brevis: while life is short, art endures.
Article and photography reprinted with permission from the National Concrete Masonry Association.