Construction in the Fast Lane

• By Corrina Stellitano
• 06/01/04

One thing is certain: like the shoes of a fast-growing teenager, most schools in Florida will be outgrown almost as soon as they are put into service. Florida has long been known as an area of explosive growth; year after year, the frantic statistics support that perception.

According to the Florida Office of Economic and Demographic Research, the youth population (ages 0 to 19) of Florida grew 25.2 percent in the 1990s. By 2010, that group is projected to grow to 4,495,447 (23.7 percent of a projected state population of 18,978,666).

For Florida school administrators, these numbers are no surprise. Keeping pace with the surging numbers of school-aged children has almost become an exercise in futility. Even new schools are often at 120 percent of capacity on opening day.

For years, the answer to this overcrowding has been the introduction of small portable buildings that house single classrooms. More than 20,000 of the“temporary” (but typically never moved) classrooms are already in place at Florida schools. Adjacent to the traditional Florida school architecture, these portable villages on stubby stilts are an expanding reminder of the state’s race with population growth.

One Florida district, Miami-Dade County, has found another answer: quick modular construction that allows multiclassroom buildings to be completed in only four months. This solution is particularly attractive now that permits for this type of construction are valid across the state.“This is hugely significant for the Florida school districts,” explains Tania Tzamtzis, an architect with Spillis Candela DMJM. “Now, they can take advantage of the very short construction schedule this modular construction allows, without being delayed by an extensive permitting process.”

Raising the Difficulty Level

Being able to build school facilities quickly has become increasingly important in Florida. The race to accommodate the population explosion has been transformed into a virtual obstacle course in the past several years, with two legislative acts officially pressing school districts to respond to overcrowding.

During a 1997 special session on school construction, Florida legislators demanded that by 2000, all temporary classrooms should meet state standards for accessibility, wind resistance, technology connections and heat or smoke detectors. (They later extended that deadline to 2001.) They handed down another strict mandate: all portable classrooms more than 20 years old would have to be eliminated by 2003. The use of other portables was to be reduced by half.

Then, in November 2002, voters approved Amendment 9, which imposes strict limits on the size of public school classes. By 2010, kindergarten through third-grade classes are to have no more than 18 students, grades four through eight must have no more than 22 and high school classes must have no more than 25 students. And, suddenly school officials, faced with the typical two-year construction schedule on classroom additions, were considering adding portable classrooms, rather than removing them from service.

It was in this political context that the Miami-Dade County public school system began to consider other possibilities for school expansion. Working with Spillis Candela DMJM and the James B. Pirtle Construction Company, the Miami-Dade school district surveyed a variety of manufactured (or prebuilt) building forms. The option finally chosen, though, was the fast and inexpensive on-site construction of sleek contemporary education facilities at 10 locations throughout the county; five more projects are currently in the planning stages.

Carlos Hevia, executive director of Capital Improvements for the district, describes the modular buildings: “They’re beautiful,” he says. “Everyone loves them. In the modern schools, they blend in because they are sleek and streamlined. They can also be made to match the color of even our older Mediterranean architecture, and they certainly match a lot better than the portables.” However, arriving at this solution required research and cooperation from all involved.

From Manufactured to Modular

Miami-Dade school district officials had first envisioned using manufactured buildings that would arrive on the school campuses in one or several pieces, virtually completed. The producers of these manufactured buildings have long boasted of their ability to beat the costs of conventional construction.

For several months, the school district worked with construction experts and Spillis Candela DMJM — a design firm with some 30 years of experience working with the Miami-Dade school district — to research manufacturers in Florida and in other states. “We assembled a team and we worked together as a team,” says Hevia. “It was an all-inclusive effort.”

The manufacturers’ responses were something of a surprise numerically, recalls Wayne Gregory, project manager for James B. Pirtle Construction Company.“The manufactured buildings cost more per square foot than we thought we would have to spend to build conventionally,” says Gregory. “At the time, we were looking at buildings with six to eight classrooms. And since these buildings didn’t have to be mobile like the old portables, it didn’t make sense to pay more for a temporary, or portable, building.”

The initial concepts presented by the manufacturers ranged from $76 to $121 per sq. ft., and none of them totally complied with MDCPS design criteria. Traditional school construction costs an average of $120 per sq. ft. (however, this includes site work). The prototype of the modular buildings eventually built for the Miami-Dade school system cost only $72 per sq. ft., not including site work. This breaks down to $2,480 per student station.

Once these figures were in hand, Miami-Dade was advised to consider a more conventional form of construction: modern tilt-up concrete panels, which are often used in school construction in Florida. The news was met with relief, recalls Tzamtzis. “The district was much happier with that because, as good as some of the modular buildings were, they still looked portable,” she says.

Spillis Candela DMJM worked with the James B. Pirtle Construction Company to design a series of classroom buildings. The variations featured seven, nine, eleven or thirteen 750-sq.-ft. classrooms. Additionally, all prototype buildings were equipped with both male and female group bathrooms. The buildings would be connected to existing facilities with a metal-covered walkway.

The design criteria for such educational projects are typically very detailed. This project was no exception, says Tzamtzis.

“The buildings have to comply with Florida building codes, including the hurricane and wind impact concerns, and Miami-Dade County has its own criteria for air conditioning, life and fire safety, percentages of impact-resistant wall finishes, ceiling height and other factors,” Tzamtzis says. Ceilings were required to be nine ft. high; doors must be recessed so that they don’t swing into corridors.

Bidding out the project built with tilt-up concrete panels led to another pleasant surprise, Gregory says. “After Spillis Candela DMJM finished the drawings, we bid out to subcontractors,” he explains. “We were surprised that they were able to beat both our budget estimate and the cost of manufactured buildings. Best of all, we can construct these buildings as fast as a builder could deliver manufactured units.”

Construction in the Fast Lane

With the help of more than 22 subcontractors, the modular buildings can be built very quickly. From groundbreaking to occupancy, the modular school buildings take only four months to complete. “Since some of the new schools are already overcrowded, we needed a quick solution that allows classroom construction to keep pace,” says Gregory.

The modular buildings are built of concrete tilt panels — some as large as 26 ft. — that are poured and erected on site. Windows, including one for emergency egress, are designed to provide the ventilation and natural light that are required by code.

Windows were one pertinent example of the factors governed by the school district. “We have very specific parameters for our windows,” says Hevia. “We require integral metal louvers that control light from the outside, without the need of a blind or curtain. These also increase security and protect occupants in the case of a hurricane.”

The roof structure is a traditional metal deck fastened to supporting steel. Modified bitumen covers the rigid insulation that tops the metal deck. To minimize exterior maintenance, the roof drains to external downspouts and external filtration trenches.

Inside, the buildings are sleek, streamlined educational facilities that have been optimized for easy operation and maintenance. Each classroom in the modular building is entered from a wide and airy, interior, double-loaded corridor (and each has access to the gleaming male and female toilets provided within the building).

Tributes to modern education protocols, the classrooms are each filled with two large marker boards, four tackboards, a television and five computer stations, a teacher’s desk and technology center, and 30 student desks. Smaller rooms house electrical equipment and janitorial supplies. Surfaces inside are easily cleaned and painted. Bathrooms are lined in shiny tiles.

In school buildings, everything should be very streamlined, but with the priority on safety. “It doesn’t feel like a portable, because it isn’t,” says Tzamtzis. “It is a regular building from the outside and the inside.”

A Seller’s Market

The modular buildings are so attractive that everyone wants them. Rather than the construction process being an issue, site selection is the true challenge, project planners say. The building was the easy part; the units themselves are practical and quick. Trying to determine who would get them first and where they would go was the difficult part,” says Hevia.Competition was fierce, recalls Tzamtzis. “Most of these schools are extremely overcrowded,” she says. “We had a priority list of locations, but the list kept changing because everyone wanted the buildings.”Once Spillis Candela DMJM completed its design criteria and subcontractor bids had been received, Miami-Dade fixed the price of the four prototype buildings. Now, each time a site is chosen, Spillis Candela DMJM develops site work adaptation drawings, and James B. Pirtle Construction Company bids that portion of theproject separately. That price, combined with the predetermined building cost, is submitted to the school board for approval.

To keep the projects within a very compressed construction schedule, the team first researches each site to identify potential delays. “They want to complete these quickly and not have to move utilities, so we have to conduct research first,” says Tzamtzis. “The site planning of every building is a challenge.”

The buildings must be located near enough to existing buildings to enable connection of the covered walkway and the fire alarm, intercom, security and electrical systems. Locations that would require lengthy site preparation, such as the relocation of a sewer line, are often eliminated from consideration.

“Because we are building on existing sites, we do site investigations to reduce the number of surprises and to ensure that we won’t have an overrun in our cost per student station,” says Gregory. “Our approach is to minimize those sorts of surprises so our project , is a little more manageable. We’ve probably investigated five times more sites than we’ve built on.”

Careful preparation and cooperation can mean a quick and attractive bottom line, planners say. And, an open mind helps, too.

“Our design criteria are very strict, and generally, we have specific ideas about what we expect from a project. But in this case, we were very inclusive and asked for input from all sides. When history has shown the best way to do something we stay with it, but we had never done modular construction on this scale,” says Hevia. “In certain areas, I could imagine whole schools being built this way. It optimizes space, minimizes costs and saves a lot of time.” And with Florida’s burgeoning youth population already straining the seams of existing school facilities, construction time is of the essence.