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Let’s Take Prefab Back One Classroom at a Time

Architects have the knowledge and expertise to make pre-fab and modular building relevant (and appealing) to everyone

By Yu-Ngok Lo, AIA

It’s a sad irony of pre-fabrication that after 100 years of pondering by the greatest minds in architecture (Mies, Gropuis, Fuller, etc.) its most omnipresent examples are often its worst: suburban cookie-cutter stick-built houses and portable classroom trailers. The Los Angeles Unified School District’s recent competition to design a pre-fabricated school building that’s flexibly attuned to its site and ecologically sustainable is a stark counterpoint to the way most of the nation’s children experience pre-fab: inflexible, disposable, unsustainable, and even unhealthy boxes hunched in the parking lots of schools lacking the funds to renovate or expand.

The first thing this competition did right, quite frankly, was to invite architects to the party. Many portable classrooms roll off assembly lines without any kind of architect supervision. Public clients like schools will always be in need of budget-conscious design interventions, and it’s up to architects to make the case that pre-fab works best when it’s about much more than fabrication and installation.

What is a portable classroom?

Portable classrooms are primarily designed for temporary uses, and have the ability to relocate to other campuses when needed. They are pre-designed, pre-engineered structures with standardized sizes. They are typically supported by a wood foundation and raised from the ground with ramps. Generally, they are purely functional, with very few aesthetic flourishes. Nonetheless, many classrooms ended up being used longer than originally intended, and sometimes became permanent solutions. More than 79 percent of portable classrooms are used for longer than two years according to a report by the San Francisco planning and design firm MKTHINK.

In a typical scenario in California, a school district hires a design team to help the district determine the location of these buildings on its campus. The design team is responsible for obtaining fire- and life-safety approvals for the site work, and for providing bidding documents for the utility services for the buildings and associated site work. They are also responsible for coordinating utility needs with the portable building manufacturer and assisting the owners to determine colors and other special requirements. The delivery schedule of buildings and completion date of the foundation are closely coordinated between the building manufacturer, site contractor, and construction manager.

Advantages and disadvantages

Obviously, portable classroom buildings offer great flexibility to school districts in terms of spatial needs. Since most portable buildings are constructed in a manufacturing plant, prevailing construction wage requirements are not applicable. As a result, the construction costs are significantly lower compared to traditional design-bid-build structures. Also, the standardized designs allow for more efficient fabrication and faster construction, which is critical to many school districts due to the limited construction time available during summer.

Architects are usually not involved in the purchase of these buildings, have little influence on their design, and have no control over what materials the building manufacturer uses. When making these (supposedly) short-term investments in teaching infrastructure, quality materials and finishes are seldom high priorities. Furthermore, the standardized designs of these buildings does not respond well to varied and distinctive sites. Specific climate regions and architectural contexts are often ignored. The form of these buildings is predetermined and the choices of finishes are limited.

It’s difficult and rare today to make an aesthetically pleasing prefab, portable classroom. Considering how many formative years the next generation of Americans will spend at school, that’s a sadly missed opportunity. Furthermore, portable classroom HVAC systems rarely perform up to traditional standards. The initial cost of the HVAC system is usually low, but includes high maintenance costs during the lifespan of the building. There are other HVAC problems as well when compared to normal classrooms, as revealed by a California Environmental Protection Agency and Department of Health Services report. These include higher rates of dirty air filters (40 percent vs. 27 percent), blocked outdoor air dampers (11 percent vs. 3 percent), and poor condensate drainage (59 percent vs. 12 percent), which can lead to microbial contamination.

The opportunity for architects

Because portable classrooms are pre-designed and pre-approved with standardized layouts, the architectural industry loses a millions of dollars of revenue every year to this kind of prefab. Although this number might be insignificantly low compared to the more than $9 billion dollars of design fees earned by the top 250 architecture in 2010, it might still have a dramatic impact on small architectural firms, especially in such a difficult economic climate.

The quality of portable classrooms has been improving over the years, and sustainability has become a priority due to its marketability and (in California) the new CALGreen construction code. Take the Bolsa Knolls Middle School in the Santa Rita Union School District as an example: Constructed by American Modular Systems of Manteca, Calif., the buildings are made with high amounts of recycled materials with low VOC content. According to School Construction News, the HVAC systems of these classrooms exceed the energy efficient standard set by California by more than 30 percent.

The benefits of portable and modular classrooms are easy to understand. They offer great flexibility in terms of construction schedules and great economy in terms of construction costs. However, design professionals should take the lead in providing better solutions. The idea of a prototype classroom (like the ones being developed in Los Angeles) that applies designers’ talents for creating uplifting spaces in combination with the efficiencies of factory production should be seriously considered. These efficiencies can be harnessed by designers and steered into projects that are more affordable, efficient, and pleasing to the user. More studies related to the site’s climate conditions, which affect building orientation, fenestrations, and passive and active cooling and heating strategies, are desperately needed. Furthermore, the color, formal expression, and choice of materials in these projects need to create a relationship between the existing buildings on campus. These fundamental tenets of architecture can’t be ignored. Portable classrooms, like traditional architecture, should respond to the unique social and cultural issues presented in each site, and should not be overshadowed by buildings whose only ambition is bottom-line value, often confused as “sustainable” or “efficient” architecture. Buildings that no one likes--and were never made to be liked--are never sustainable.

Recent Related:

Michelle Kaufmann Scales Down to Scale Up Prefab

KieranTimberlake Moves Pre-Fab Into Mass-Customization

Method Homes Pre-Fab Prototype Walks the Middle Path

99k House Competition Builds New Tradition of Affordable Sustainability

Solar Decathlon Advances Affordable Sustainability

Wee Fit: Prefab Construction for Small (and Not so Small) Spaces

Experimental Prefabricated Home Built from Sustainable Lumber

KieranTimberlake Designs Expandable Home and Flexible Townhome


See what the Committee on the Environment Knowledge Community is up to.

Visit the Modular and Prefabricated Architecture Group on AIA KnowledgeNet.

Do you know the Architect’s Knowledge Resource?

The AIA’s resource knowledge base can connect you to “Performance and Manufactured Homes,” by Linda Reeder, AIA.

See what else the Architects Knowledge Resource has to offer for your practice.


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