Airtight homes eyed as mold issues grow

Memories of the oil embargo three decades ago that produced long lines at gas stations have been short-lived for Southern Californians who still love to drive gas-guzzling cars. But those days did spur energy conservation changes in residential construction that remain today.

Since the 1970s, homes have been built increasingly airtight to save on gas and electricity. Some observers, however, believe the practice has increased problems with indoor air quality and resulted in higher incidences of household mold. But not everyone links the increase in mold concerns to building practices. Also on the list of potential culprits are certain building materials and the habits of homeowners themselves.

“We find more problems with recently built homes compared to the ones built before the oil embargo of the 1970s,” said Jim Kingsrud of Home to Home Inspections & Consulting in Laguna Hills. “We are seeing a lot more of the stachybotrys -- that’s the one that all the hype is about.”

Kingsrud’s inspectors see mold problems in everything from older retirement homes to high-quality new town homes, apartments and single-family residences. The reasons for the mold, he said, range from improper maintenance to construction defects. The issue of a home being airtight just complicates the problem.

An energy-efficient, airtight home -- one that has doubled paned windows, heavy insulation and weather stripping around doors and windows, for example -- does not cause mold itself. But when moisture enters through a plumbing or rain leak, it can become trapped. When such leaks are unnoticed and untreated, mold can begin growing in as little as six hours. Among the mold types are everything from mildew to sometimes toxic varieties that can cause serious illnesses, such as stachybotrys, penicillium and aspergillus.

“Mold has been around forever, but we are seeing more of it now because of the construction industry,” said Johnny Zamrzla, owner of Palmdale-based Zamrzla & Associates, experts in water infiltration in homes. “It’s because they are making construction tighter.”

High-profile court cases, such as the $7.2-million settlement over the death of Ed McMahon’s dog and a $32.1-million jury award to a Texas homeowner that was later reduced to $4 million, have brought media attention to the mold issue.

And while some blame airtight construction, members of the California Energy Commission, created in 1974 in part to promote energy efficiency through appliance and building standards, don’t view their recommendations as part of the problem. The positives of building airtight homes, which can save up to 75% a year on energy costs per home, far outweigh any negatives, said spokesman Rob Schlichting.

“For the most part, we are better off now living with energy-efficient homes,” he said. “I don’t think there is a correlation between airtight construction and mold.”

Others blame the construction industry and building defects. In the push to build homes to meet rising demand, more unskilled labor is being used and corners are sometimes cut.

“Energy-efficient homes are a good thing,” said Sandy Skipper-Lopez, the national director of Homeowners Against Defective Dwellings. “But energy-efficient homes improperly constructed ... are a recipe for disaster and make homes Petri dishes for mold.”

Another culprit is the use of more porous building materials, such as plywood and drywall made of organic materials, which can become prime food sources for mold.

Foundations in particular are being blamed. Continuous footing foundations, which have become more commonplace since the 1994 Northridge earthquake, are often involved, said John LaRocca, a longtime Los Angeles-based inspector and licensed general contractor.

With a continuous footing foundation, a series of 6- to 8-inch-thick walls are spaced underneath a home to support the foundation. The spaces between these walls can create pockets of trapped moisture, which can be absorbed through the building materials and seep into a home.

“That can create a mold problem,” LaRocca said, “or at least set up the potential for it.” For their part, homeowners contribute to the potential for problems by keeping their homes closed up because of, among other reasons, safety concerns.

Everyday activities, such as bathing, cooking and even just exhaling increase humidity levels. Indoor saunas, hot tubs and clogged clothing dryer vents also contribute. Without proper ventilation -- using a fan or opening a window or door -- mold problems can occur.

“Fans in the kitchen aren’t for smoke control,” said Bob Raymer, technical director and licensed engineer with the California Building Industry Assn. in Sacramento. Fans are for ventilation and humidity control.

“Moisture from the shower, if a window is not opened, adheres to walls and sooner or later there’s moisture in your house,” Raymer said. “You do that enough and you start to feed the mold.”

At the root of the problem, Raymer said, is improper ventilation.

Keeping homes healthy is an evolving science that requires a mindset change by builders and homeowners, said Kathleen Guidera, executive director of the Minneapolis-based Energy and Environmental Building Assn.

“Everyone needs to take responsibility on this issue,” she said. “A perfectly well-built house can be totally screwed up by the homeowner.”

Additionally, Guidera noted, building codes nationwide are lagging. But Texas is leading the way in potentially changing the way homes are constructed to help alleviate the problem.

The Texas Residential Construction Commission was created in 2003 in part to help reduce lawsuits between homeowners and builders and to help develop better construction-industry standards to increase ventilation in homes while reducing the incidence of mold.

“I think you can build a home that is going to allow the structure to breathe and keep moisture levels at a proper level so you can have an energy-efficient home at the same time,” said Stephen Thomas, the commission’s executive director.

California is doing its part to address the issue too, having passed two pieces of legislation in 2001 related to mold. One requires homeowners to disclose the incidence of mold to prospective buyers. The other set up a taskforce to research mold and its effects on health and to make recommendations on remediation and possible changes in construction. The task force is behind schedule, primarily due to budget cuts.

“I am on a fact-finding mission,” said Pamela Davis, a policy analyst with the California Research Bureau, a state agency think tank that researches various issues for the state Legislature. Davis, who also is a registered nurse and specializes in toxins, said she planned to issue a report to the Legislature next year.

“I would imagine we will see some changes in the building codes over the next few years because of the research,” she said. But, she added, “I don’t think we are going to make leaky buildings again.”

Instead, Davis said, she believes tighter buildings will remain but will have more provisions for better ventilation.

But for the moment, Davis’ advice? “There is no substitute for opening up the windows,” she said.

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Allison B. Cohen is a Los Angeles freelance writer. She can be reached at a.cohen@ ix.netcom.com.