[Add-On Services] The Great Crawlspace Debate

Features - Add-On Services

Two well-known PMPs are strong advocates for closing crawlspaces as the practice significantly improves moisture control and, when done properly, results in considerable energy savings.

April 30, 2012
Christine Brazell

Ten years ago, if you had asked Paul Hardy, technical director for Orkin, Atlanta, Ga., what he thought about closing crawlspaces, his immediate response would have been “No way.” And when Billy Tesh, president, Pest Management Inc. (PMI), Greensboro, N.C., presented the idea of closing crawlspaces at NPMA PestWorld in the early 2000s, he joked that “90 percent of the people in the room thought I was smoking something.”

Last October, Hardy and Tesh teamed up to present “The Great Crawlspace Debate” at PestWorld 2011. However, it wasn’t much of a debate because both agree that closing crawlspaces will be the norm within the next 10 years.

Why? For starters, the service offering is a lucrative business builder that helps increase profit. In fact, PMI generated $2.7 million closing 600 crawlspaces in four years, from 2006 to 2010. In addition, it’s good for the environment, reduces liability, improves indoor air quality, offers green-builder benefits and delivers results in terms of energy savings and health-related issues to customers.

Why care about crawlspaces?
High moisture levels in crawlspaces are a recipe for trouble. Insects, wood decay fungi and mildew all thrive in these areas. However, for years, building codes and common building practices required the ventilation of crawlspaces with outside air as the primary means of controlling moisture.

“In 1979, my dad installed air conditioning and dared us to turn the thermostat down past 80 degrees. We didn’t, and we were comfortable. Today, people turn down air conditioning much lower than the outside temperature, affecting the dew point, which leads to condensation inside,” Tesh said.

Tesh compared it to when you take a can of beer outside on a hot summer day. Any surface temperature below or at the dew point will condensate moisture.

As such, many homes built on crawlspace foundations in geographies with higher humidity levels suffer from poor moisture management that not only creates conditions conducive to insect infestations, but results in other ailments, including uncomfortable humidity, mold growth and musty odors and condensation on the insulation, ductwork and piping, as well as buckling hardwood floors, rotting framing and structural failure. And adding more wall vents won’t help. It only exacerbates the problem.

“We always talk about conditions conducive for insects, but don’t talk much about the moisture and where it comes from and what causes it. Weather conditions, construction elements, poor drainage, bathtub and shower-stall humidity, refrigerators, freezers, air conditioning units — all of those create condensation and result in moisture problems within the structure,” Hardy said. “Plus, there are other factors involved. For instance, moisture rises, so you can have 10 or 11 gallons of water rise under a structure for every 1,000 square feet under the structure.”

Another common problem occurs during flood conditions, as that rapidly creates mold, fungus and mildew problems. Orkin had closed the crawlspace in a house in Cocoa Beach, Fla., six weeks before a hurricane arrived dumping 15 inches of rain in a short amount of time. Orkin’s Todd Kemp suspected the house might be flooded and discovered a foot of water in the crawlspace.

“Todd thought quickly on his feet, brought in a generator and re-established the sump pump to pump the water out,” Hardy related. “Seven weeks later, the house doesn’t have any mold, fungus or odor.”

Based on successful company experiences and substantial research using sound science, Hardy and Tesh are now strong advocates for the closing of crawlspaces as the practice significantly improves moisture control and, when done properly, results in considerable energy savings.

Sound-science support. Hardy was first exposed to closed crawlspaces when he participated in various energy-house projects over the years, but it was one home in particular that really piqued his interest. One of Orkin’s termite customers had a home with 2,000 feet of crawlspace showing signs of mold and mildew.

The customer’s two children had breathing-related problems including severe allergies and rhinitis. So they installed vents and polyethylene, yet didn’t achieve the results they expected.

“The customer had been researching closed crawlspaces and asked us if that was something we would do. So, we cleaned the floor and closed the crawlspace, and within six months, the children no longer had problems with their breathing and rhinitis,” Hardy said. “That’s when I decided it was time to start learning more about it.”

Tesh was faced with similar issues related to moisture control and keeping customers satisfied, and wanted to make sure the company’s evaluation of closing crawlspaces was based on sound science. As such, from 2001 to 2006, Tesh joined the Crawl Space Research and Deployment Project funded by the United States Department of Energy and Advanced Energy, an independent non-profit corporation that works with utilities on energy efficiency, improved air quality and sustainability.

The team studied 12 homes in North Carolina that were all built to the same specifications with one exception: the crawlspace. Four were vented to code; four were closed crawlspaces with insulation between the floor joists; and four were closed crawlspaces with wall insulation.

“A flood had wiped out the community, so we were able to build new homes that were exactly alike, creating a scientific platform for us. We monitored everything inside and out,” Tesh recalled. “In the closed crawlspace homes, the dew point remained low. In the wall-vented crawlspace, the dew point was the same as outside.”

The goal was to find out if it cost more to close the crawlspace than it saved in energy. The results showed that the homeowners with closed crawlspaces and wall insulation were able to save 18 percent annually — substantial savings considering these homes were built to today’s standards.

“Think about all of the 25-year-old homes you run across today. Obviously, we can’t monitor because each home is different, but our customers are telling us they are seeing 50 percent savings — that’s very significant,” Tesh said.

Rather than following the traditional practice of adding vents to crawlspaces to solve moisture issues, a growing recommendation is to close in the crawlspace to keep moisture out.


What’s to come? Tesh encourages other pest management professionals to get involved with green-building committees in their local areas as well as connecting with builders, real estate agents, HVAC companies, plumbers and, most importantly, building officials and inspectors.

“One of my biggest challenges was educating building inspectors. We all know they don’t necessarily interpret the building codes the same way,” Tesh said.

As more and more entities, such as the National Association of Home Builders and the U.S. Green Building Council, require energy efficient models, closed crawlspaces will be required. The U.S. Department of Energy is also in the process of rewriting its weatherization standards for the entire country. Weatherization will need to be performed to its specifications in order to obtain funding from its programs.

But one of the most important actions the pest management industry needs to take is that of claiming the leadership position as the best source for properly closing crawlspaces.

“The pest management industry must take the lead to keep closing crawlspaces in our portfolio, because we do it right and will maintain our customer satisfaction,” Tesh said. “We’re seeing a trend that the waterproofing and indoor air-quality industries are trying to take the lead. They don’t necessarily pay attention to the details like we do.”

The author is a writer about the pest management industry. She can be reached at cbrazell@giemedia.com.


For more information on closing crawlspaces properly, visit www.crawlspaces.org. Dew-point and relative-humidity maps can be found at www.weatherchannel.com.