The Material Difference
Why architectural design must consider climate and materials to succeed
A thousand years from now, archaeologists digging through the ruins of buildings will notice that they suddenly began rotting at an alarming rate beginning in the second half of the 20th century.
As they research why these buildings crumbled, they'll discover the formula: Air Conditioning + Modern Materials = Permanent damage and decay.
The culprit will have been air conditioning combined with sophisticated innovative materials, and the resulting terrible things that will have done to these structures. Air conditioning can be to buildings what steroids are to our bodies — an instant improvement that can cause permanent, irreversible, damage.
But the advent and popularity of air conditioning is only one half of the equation. Modern materials used haphazardly cause more harm than good.
The Modern Evolution of Building Materials
Before World War II, buildings were constructed from materials found in nature: Stone, trees, clay, lime, sand, and sometimes horsehair. Boards were cut from logs in the woods. A trip to the general store for nails, tar, and paint completed the job.
Inevitably, these materials, combined with construction methods and design of the times, allowed these buildings to “breathe.” Moisture seeped in but was also able to dry out.
After World War II, man-made goods began to replace natural materials. At first, gypsum board replaced lath and plaster, plywood replaced wood boards, and metal studs replaced wood.
A little later, house wrap replaced tarpaper. Vinyl and aluminum replaced the wood frames of windows. Walls and roofs were insulated, and for good measure, a layer of plastic or polyethylene — the “vapor barrier” — was installed inside almost everywhere.
Most of these materials come in large sheets that seal up buildings so they no longer breathe. And the materials themselves are not very absorbent, if at all.
Moving into the last quarter of the 20th century, there was an increasing emphasis on new-fangled energy-efficient materials like the insulation, windows, lighting, and appliances. While these items may help save money on monthly utility bills, they also deprive the building of the heat and ventilation badly needed for drying. The nearly "air-tight" results meant moisture not only condensed inside the now-cooler walls, but it couldn’t escape and it couldn’t evaporate.
It should be mentioned that new building materials didn’t develop in parallel, either. Each manufacturer was selling their particular piece of the puzzle, claiming the product was the greatest thing since TV dinners. Consumers, building materials suppliers, contractors, and architects were often too quick to adopt the latest and greatest.
Building components were replaced one by one, but no one understood the big picture. Each piece did its part but didn’t necessarily serve the interest of the building as a whole. It was like freeform jazz where different melodies were being played at the same time.
Rot set in. So did mold.
While buildings could now be mechanically cooled, air conditioning wasn’t integrated into the plan and design of the building. It was an afterthought. The air conditioning industry didn’t talk much to construction companies, let alone architects, other than to argue about space for ductwork.
It got worse.
The uncoordinated combination of high-performance insulation and sealing cold air ducts increased the potential for moisture to occur and diminished the ability to dry out. That resulted in more condensation. More cold. More rot. More mold.
Buildings aren’t like freeform jazz, though. They’re more like a symphony, with everyone playing their part of an carefully orchestrated plan.
Learning from the Past to Improve for the Future
Fortunately, things are getting better. So too is our understanding of how to build in a hot, humid climate and which materials to use and, most importantly, which to avoid. Attics are now sealed with more foam insulation, and less polyethylene is used. High-performance air conditioners are paired with old-fashioned dehumidifiers.
Space Age coatings on glass cut 75 percent of the sun’s heat without hindering views or distorting color with unnatural tints.
Beyond improvements in materials and construction, we have seen a return to age-old principles of vernacular architecture: Think of the buildings created in the pre-industrial era — simple, practical space built with local materials and knowledge.
““By always keeping the climate in mind when we design buildings and select materials, we can avoid rot and mold, provide a “healthier” building environment, reduce energy consumption, and reduce maintenance in the long-run.””
These principles include careful consideration of the building's orientation to minimize heat gain, provide shade, and create cross ventilation that allows cooler air to circulate and excess moisture to evaporate — all of which reduce energy consumption.
Incorporating newer systems into a well-designed building while avoiding unwanted condensation and mold require the services and expertise of skilled professionals. Anyone can go to a big box store and buy plywood or weather stripping, or get advice on double-glazing or vinyl siding, but all these pieces must be holistically integrated to maximize their effectiveness.
Making all this work in concert is like composing and directing the symphony. With their skills and education in design, building materials and techniques, code requirements, and understanding of your vision, an architect brings a unique understanding to their role as conductor. Guiding the orchestra, your architect can help keep all the musicians on the same page, and might even bring in the HVAC (heating, ventilation and air conditioning) engineer to help turn the pages.
Joyce Owens, FAIA RIBA
A previous version of this article appeared in Joyce Owens’ “Architect About Town” column in the Fort Myers News-Press.
