Piecing It Together
- By Amy Milshtein
- July 1st, 2009
Choosing the right building envelope involves taking many variables into consideration. Ease and cost of construction, the time frame allowed, the desire for energy efficiency, and even the construction season all come into play. And, of course, aesthetics assume an important role as well. Depending on your school’s needs, precast concrete or Insulated Concrete Forms (ICF) might just be the material you’re looking for.
Precast: It’s Not Just for Parking Garages Anymore
Precast concrete has been around since the ancient Romans poured the first aqueduct. The material is natural and very robust. “I just drove by the first school dormitories done in precast the other day,” recalled Bob Adams, vice president of business development, Oldcastle Precast Building Systems, “and they look as good today as they did when they first went up.” The buildings in question, 16-story and 17-story high-rises for the University of Delaware, were built in 1971.
Adams admits that precast has the reputation of being inflexible and easy to identify because of its monotonous repetition. One of their latest projects should put that reputation to the test, however. The University of Scranton recently completed a residence hall project, Condron Hall, completely out of precast, and could not be happier with the aesthetics or performance. “People think ‘parking structure’ when they think of precast,” said Don Flynn, AIA, LEED-AP, vice president, Burkavage Design Associates. “To be honest, I was skeptical at first. I thought the project would look too flat.”
Precast had one great advantage going for it from the start, however: speed of construction. “We were selected for the project in April of 2007 and students needed to move in by July 2008,” explained Flynn. “The school expected the building fast and needed it constructed through the winter. That’s not easy to do in this climate.”
When the construction manager suggested precast, Flynn had his doubts. But after working to understand the system and how to design within its vocabulary, the architect and his team learned to operate within the product’s standards. For instance, repetition is an important rule for precast, as is a large floor area. “The economy comes from the size of the panel used over and over,” explained Adams. “More floor area per square foot of walls make precast more efficient.”
But that repetition doesn’t have to translate to monotony. Flynn and his team hid the seams and changed colors and materials often to add interest to the façade. The result is a handsome, durable building that today houses 386 sophomores in two-bedroom, suite-style rooms. “The material is also dense, which makes it acoustically desirable for a college dorm setting,” Flynn continued.
School, donor, and architect remain very pleased with the end result, and Flynn insists that, under the right conditions, he would use precast again. “We paid a bit of a premium in the analysis stage, but it was worth it in the end,” he explained. “If you need a structure quickly or something built over the winter, precast is the way to go.”
ICF: Is This New Grid On the Block Here to Stay?
Another modular option on people’s radar these days is ICF, or insulated concrete forms. “They are kind of like giant, insulated Legos,” explained Kenny Stanfield, AIA, principal, Sherman Carter Barnhart Architects. The system brings a lot to the table. “Since everything is all-in-one, they make construction fast and easy,” said Toddy Blyth, marketing manager, NUDURA. “Basically it combines six building steps together.”
Speed isn’t the only advantage to ICF. The system contributes to a building’s energy efficiency. “I’m totally focused on energy performance, and products like this really get the job done,” said Ken Seibert, president, CMTA Consulting Engineers. “Of course there’s lots of expensive ways to up efficiency, but this is also an extremely practical solution.” In fact, using this product makes the building envelope so efficient that mechanical sizes can be reduced. “We are working on the nation’s first net-zero energy elementary school in Kentucky’s Warren County, and we predict that it will use 18 BTUs per square foot per year,” raved Seibert. “ASHRE’s current standards dictate 73 BTUs.”
Energy efficiency poses a powerful argument to use ICF, but the material’s inherent flexibility ensures that design will not suffer in the process. “Architects can specify any radius they desire,” explained Blyth. “You can do anything with this that you can with traditional building materials.”
“Curves are no problem,” agreed Stanfield. “I just completed a high school that featured huge curves along both ends.” Along with form, the material can be skinned with any veneer, from brick to synthetic stucco or metal panels. “The building can look traditional or contemporary,” Stanfield insisted.
There are drawbacks, of course. Because drywall must be used on the interior to meet fire codes, some schools worry about durability and maintenance. “When you’re used to concrete block, drywall, even high impact drywall, can look like a problem,” said Stanfield. Another issue is getting tradespeople on board with a new technology. “Compared to masonry, our first ICF school was $2 a square foot more,” he continued. “That was three years ago. Now we have 14 of them, and they are comparable in price.”
“People are always adverse to change,” agreed Seibert. “But the learning curve is worth paying for.”