The Three Dimensional Egg
The Green Spaceship," as students have aptly nicknamed the Lake Zurich Elementary/Middle School, captures the essence of the 220,000-square-foot facility, which is both green in design and operation, as well as in terms of its aged-copper face. In addition, its non-traditional classroom and cafeteria ceilings allowed for exposed structures without the loss of speech clarity.
The innovative, sustainably-built structure in Hawthorne Woods, Ill., is sited on a 31.5-acre plot, which previously sat vacant as farmland. The showcase of the facility is its copper-plated "three dimensional egg," separating the elementary school and middle school wings, Spencer Loomis Elementary School and Lake Zurich Middle School North.
The $28 million two-in-one school with an egg-shaped copper-plated entrance has a total classroom capacity of 1,300 students.
"Administrators could do additions to add 300 students without increasing the size of the core," said Project Architect Patrick Brosnan of Legat Architects. "It is basically an H-plan, the bottom half of the H is the elementary school and the other half is the core facilities: athletics, kitchen and receiving areas."
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PROJECT DATA Architect: Legat Architects Inc. |
The advantages to combining schools were significant. Combined mechanical systems allowed for a heat recovery VAV mechanical system with ice storage. Combined kitchen and receiving allowed for a full-service kitchen instead of a warming facility. And adjacent athletic areas yield to community use.
The idea of the whole athletics area is that we designed the elementary school gym and two middle school gyms, to be accessible off of one common corridor, explained Brosnan. "So for community use you can have access to all three of those spaces, you can have one entrance-and-exit point for access to parking," said Brosnan.
Sustainability
The facility is an innovative and well designed structure, with very clear separations. "Our goal was to do as much as we could in terms of sustainability, while still remaining in budget," said Project Manager David Voss of Legat Architects.
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The floor plans for the Lake Zurich Elementary/Middle School reveal multiple curvatures. The stand-alone "egg" structure serves to separate the two schools. Differences between the wings are evinced, as the Spencer Loomis Elementary School is a straight block, and the Lake Zurich Middle School North is a long curve. |
The exterior of both the elementary and middle school wings is brick, and Legat chose to use a darker brick for one wing and a lighter brick for the other. The bricks work together to keep the continuity of the single structure. The choice of brick modules reduces waste.
Energy-efficiencies are manifested via low-E glass throughout the facility replete with exterior sunshades, low-VOC adhesives for carpet, low-VOC paints and low-VOC spray-in-place insulation, and fire stopping insulation that meets Canada’s "Environmental Choice" certification.
There is low-E insulated glass everywhere. The low-E coating on the glass reduces the amount of solar heat while permitting daylight to enter. The insulated glazing gives a higher R-value and therefore saves energy. Classrooms are oriented to face directly north and south. North and south light is excellent for classrooms, according to Legat, and the optimal solar orientation.
The building is oriented to maximize the sun’s heat and contains sunshades on the south and west faces. The sunshades account for the path of the sun throughout the four solstices; placement is both in the horizontal and vertical directions.
The south facing windows have horizontal exterior sunshades designed for 100-percent solar shading on the summer solstice. Vertical solar shades reduce some direct solar gain on the west facade. The sunshades reduce the amount of direct sun, or glare, and reduce the solar heat entering the building.
Light shelves on the inside of the windows reflect daylight deep into classrooms. Corridor walls have clerestories that allow light to filter into corridor from light shelves.
The wood gym floor is made of Forestry Stewardship Council approved Smartwood. The wood used was harvested from a forest complying with strict environmental guidelines and assures that the wood was not clear-cut.
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Casework in the second-story library follows the entire perimeter of the "egg." The countertop is custom and it had to fit the exact curvature of the walls. |
There is a heat recovery system that reduces the amount of energy consumed for ventilation. There is an ice storage system that freezes ice at night when the utility company’s rates are lower. Also, it reduces load on the chillers during the day allowing them to be sized more effectively to an 80-percent efficiency running rate avoiding large swings from low to high loads, which uses a lot of energy.
Acoustic Creativity
The school’s non-traditional classroom and cafetorium ceilings allowed for exposed structures without the loss of speech clarity. A sprayed-on acoustical plaster finish and acoustical wall panels control reverberation.
"The cafetorium was a very unusual space, the main reason was that one of the walls is wide open to the common space so rather than it being a room with four walls, it only had three," explained Greg Miller, senior acoustics consultant, at Talaske.
The key to that room is the ceiling, which is around 28 feet. "The wood panels were really the most important feature of the room acoustically," said Miller. "The key with the panels is that they actually reflect sound, they contain sound within the room. They function like a ceiling. We worked with Legat very closely and spent several weeks going back and forth to get the height and the angle of the panels just right."
The wood panels that drape across the cafetorium are veneer plywood, not a solid core. The panels help to keep the sound inside the room preventing its escape into the larger area that surrounds the egg. The ductwork above is the acoustic deck manufactured by Epic.
In the classrooms, the design called for non-traditional ceilings and Legat wanted to convey a lofty, airy feel. The classrooms have an exposed ceiling structure, both in the middle school and elementary school, that spans heights up to 12′-3".
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| “The Green Spaceship” is how some elementary and middle school students refer to their school. The copper-plated structure is separated from the classroom wings by a glass curtainwall, and is a freestanding element with its own roof system. |
"The things that were the most interesting from an acoustical standpoint in the classrooms is we wanted to expose the structure above, so we used a material that is very similar to fireproofing but is specially designed to absorb sound, to achieve a high degree of speech clarity," said Miller.
"We applied a surface finish, a spray-on, cellulose-based material, which offers a high degree of fireproofing and absorbs the sound," explained Miller, "so that students could clearly understand what was being presented in the classroom."
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PRODUCT DATA Construction Materials Acoustic Products Furniture Carpet and Flooring Washroom Equipment/Supplies Physical Education Equipment HVAC Miscellaneous |
Legat’s classroom design began with the idea of raising the ceilings to provide three advantages, and the acoustical advantage was evaluated and confirmed by Talaske.
Project Manager Voss at Legat, outlined the three advantages to the non-traditional classroom design. "One, it gave us the lofty, more spacious feel. Two, it offered better light distribution and lastly, greater wall area and an increase in acoustical absorption within the classrooms."
Acoustic plaster was applied to the underside of floor/roof concrete planks. By raising the ceiling height to 12′-3", additional wall area was available for acoustic wall panels. Linear direct/indirect lighting is set at 9′-4" above the finished floor, therefore the taller ceiling provides better light distribution.
The roof decks and floor decks are precast concrete. And in order to deal with the classroom’s acoustical characteristics, team members opted for spray-on acoustical insulation, "the spray-on product, in the neighborhood of 1-inch thick, had to be applied to the bottom of the precast," explained David Norris, senior project manager at Bovis Lend Lease, the construction manager.
Furthermore, the performance of the acoustic plaster was greater than that of SAT (suspended acoustical tile), said Voss.
Material Selection
The Lake Zurich Elementary/Middle School incorporates materials not commonly seen in schools; most notable is the copper-plated egg – the ellipse in the center of the building – that divides the elementary school portion from the middle school.
"In plan, [the egg] is an ellipse, and the walls that form the ellipse are sloped in," said Norris. "The egg was certainly a challenge."
The walls of the egg are not straight vertical walls; they cant in and become a truncated cone that is cut off at the top. The walls are built out of structural studs, which had to be engineered by the contractor to follow the curvature. All of the drywall partitions were curved and canted vertically.
The first floor of the egg houses administration and security in the portion that protrudes off the face of the school. On the same ground level, the inner section of the egg serves as a multipurpose room. The second floor of the egg holds the library that connects to the middle school on the right and the elementary school on the left via glass enclosed corridors.
"The library is kind of floating between the two wings of the building and also within the large open area that is the multipurpose cafeteria room," said Norris.
The challenges for Bovis Lend Lease, the construction manager, were the curved slopes in both the walls of the egg and the middle school wing, which itself is one large curve.
Casework in the library follows the entire perimeter of the egg. The countertop is custom and it had to fit the exact curvature of the walls.
Norris described the egg as if it was almost designed as a sculptural form that stands alone in the building.
"It is separated from your masonry classroom wings by a glass curtainwall and inside it is a free-standing element with its own roof system. It does not go up and touch the main roof that you see over the cafeteria; it actually is below it. It is completely its own stand-alone element or building within the structure."