Update: Spray Foam & Termite Protection

In February, PCT published an in-depth report on spray polyurethane foam (SPF) insulation and its impact on termite inspection and control.

An increasing number of homeowners, especially in the Southeast, are installing the insulation in crawlspaces and attics to improve energy efficiency. Builders are using the foam in newly constructed homes as well.

Pest management professionals, however, say that the foam makes it difficult, and at times impossible, to properly inspect for termites and wood-destroying beetles and fungi, especially when the foam covers sill plates, floor joists and foundation walls.

As a result, a growing number of PMPs are voiding the termite damage warranties of clients who have retrofitted their homes with the foam. They’re walking away from new customers who have it, and are refusing to write termite/WDO (wood-destroying organism) inspection letters for real estate transactions for homes with SPF.

NOW, FUMIGATION CONCERNS. PMPs who fumigate to control drywood termites are facing SPF-related challenges as well.

SPF is the material most-often used to create an enclosed or “unvented” attic. The foam is applied to attic walls, floors and ceilings, sealing fans and vents. (In new homes, attic fans and vents may not be installed at all.) This brings the attic into the building envelope, where it maintains a temperature similar to the rest of the house instead of reaching 150 degrees on a hot day. As a result, less energy is needed to cool the house and the comfort level for occupants is much improved.

Current fumigation aeration methods, however, rely on attic vents to draw gas out of the structure. As such, some PMPs have reported extended aeration times for fumigations at homes with unvented attics; some up to three days instead of the standard 24 hours.

In September 2018, Douglas Products and Ensystex sent letters strongly recommending that fumigators stop using Vikane and Zythor fumigants in homes with SPF in attics pending further evaluation.

“Douglas Products is actively looking into the foam issue and currently conducting our research. We do not yet have specifics available. We will communicate more once we have additional information to share,” wrote Heather Kern, commercial leader, Douglas Products, in an email to PCT. She could not provide a definitive timeline for when the tests would be completed but she expected them to wrap up before year end.

PCT was told that the company is conducting laboratory tests on the spray foam and is testing enhanced aeration methodologies in the field.

Any changes to fumigant labels and application/aeration instructions won’t happen until that test data has been reviewed by U.S. EPA, which could be spring 2020, said Jim Fredericks, vice president of technical and regulatory affairs, National Pest Management Association.

Kurt Riesenberg, executive director of the Spray Polyurethane Foam Alliance, which represents spray foam applicators, took issue with Douglas Products for singling out SPF (he said the issue is not SPF but unvented attics). He said the company has not stayed current with new building practices and materials that could impact fumigants, and for taking too long to conduct these tests.

“We want this solved and we’re all basically being held hostage for months by one company who hasn’t even finished the first stage of this process to get us to the solution of getting EPA to accept all this and have business back to normal,” said Riesenberg, who spoke to PCT in June.

Fredericks recognized the spray foam industry’s frustration. “I can understand where those folks are coming from. I also know that pest management professionals want to do this work. I know that Douglas Products wants to sell fumigant. However, this process is just being approached with an abundance of caution, as it should be. There is a scientific process that needs to be taken,” he said. Fumigants are governed by FIFRA and label changes must be carefully vetted and then approved through EPA, he reminded.

WHAT ABOUT EFFICACY? Riesenberg said some PMPs are telling customers they cannot fumigate because SPF absorbs the gas, which he said is unproven. He said he expected SPF to perform better than other insulation materials in absorption and desorption tests in the laboratory. “The gas can’t get into our material like it can between the fibers of fiberglass or cellulose,” he said.

If true, this raises another question: Can fumigant penetrate SPF to get to the infested wood behind it?

“If you have wood-boring beetles or drywood termites and you fumigate a home for those pests, if you have spray foam insulation does it affect the efficacy?” asked Derrick Lastinger, program director for the Georgia Department of Agriculture’s Structural Pest Section and chair of the structural fumigation committee for the Association of Structural Pest Control Regulatory Officials (ASPCRO).

It’s a big question, said Sean Brantley, vice president, Emory Brantley & Sons Termite, Pinellas Park, Fla., and a member of the NPMA fumigation committee. He said 4-mil polyurethane sheeting is documented as effective in confining fumigant and “this is a lot thicker than 4-mil poly when you’re talking about inches of it.”

It’s possible the fumigant could have a pathway to infested wood from the outside of the structure but with every house constructed differently and of different materials this would be difficult to evaluate, said Brantley. Plus, it likely would require a longer exposure time and that’s not feasible given weather, clients’ schedules, the cost of doing business and the additional liabilities involved, he said.

REACHING CRITICAL MASS. Unvented attics were written into the building code 12 years ago. The issue with SPF is arising now because enough homeowners have retrofitted attics and builders have built enough new homes with unvented attics to where PMPs are coming across them, said Fredericks. He also cited the lag time between drywood termite infestation and fumigation. If an attic was sealed 12 years ago and that same year termites infested it, the infestation might not be identified for another seven years due to the lag time between infestation and detection.

Finally, PMPs may have encountered extended aeration times in the past but didn’t recognize a trend until they experienced more of them. “We just reached this critical mass where we said, ‘There’s something else going on here,’ and now we’re trying to get to the bottom of it,” he said.

The letter from fumigant makers does not prohibit PMPs from conducting fumigations at homes with spray foam in attics. “For us, that letter was carefully drafted so that it was a recommendation of restriction and not a mandate,” said Brantley. But it did imply the manufacturers won’t stand behind PMPs who proceed with fumigations and run into problems, he said.

Brantley has declined to perform fumigation at some homes with spray foam; at others he has pushed aeration times and excluded SPF-covered areas from the termite warranty. He expects more PMPs to change termite warranty contract language to exclude areas with SPF. Those who don’t “should probably have some sleepless nights thinking about whether or not you’re gaining control because you’re really just spraying and praying at that point,” he said.

PMPs said spray foam also hides moisture leaks and causes condensation to form between wood timbers and the foam due to differences in indoor/outdoor temperatures. This can result in wood-destroying fungi/rot that can be missed during a WDO inspection. “It opens the door to an additional layer of liability,” said Brantley.