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Abstract
Foam plastic insulation around or beneath building foundations can provide hidden entryways that must be considered for effective termite prevention. Borate-treated expanded polystyrene (EPS) rigid foam insulation installed with construction sealant (CS) to a concrete block was evaluated for resistance to damage by native subterranean termites. The evaluation included 3-year exposure to termite attack in three widely separated test plots of insulation-enclosed concrete test units partially buried in soil, with untreated wood above and below the units to attract termites. By digital image analyses, the percentage of termite damage was quantified by treatment for field-exposed EPS samples to provide data amenable to statistical analyses. Borate-treated EPS with borate-treated CS had 3.2 percent damage compared to 23.9 percent for untreated EPS installed with untreated CS after 3-year field exposure.
In 1992, the Model Energy Code began to mandate use of insulation on and beneath building foundations to enhance energy savings (CABO 1992). This use of insulation soon became commonplace in the southeastern United States, which is a high-risk region for subterranean termite attack. This led to a rise in termite damage related to the use of insulation (Smith and Zungoli 1995a,1995b). The National Pest Management Association warned its member companies to regard all untreated insulation the same as untreated wood in contact with the ground (Kramer 1993).
Termites can tunnel through insulation and/or the interface between insulation and the foundation. Insulation enclosing entire masonry or concrete foundations (below ground and covered by coatings such as synthetic stucco) provides termite entryways that cannot be detected by inspection. Therefore, personnel with responsibility for effective termite protection in many states provide guidelines that require a 6-inch (150-mm) wide gap (inspection band) in insulation around the perimeter of foundations and have restricted its use below ground.
This study evaluates expanded polystyrene (EPS) rigid foam insulation installed in conjunction with construction sealant (CS). Combinations of borate-treated EPS and CS were evaluated along with untreated materials (Table 1). The borate-treated EPS is manufactured under a patented process (Savoy 1993) using disodium octaborate tetrahydrate (DOT). The product is marketed under the brand name Perform Guard®.
Although small-scale laboratory experiments may be suitable for evaluating contact pesticides, a field test method was developed to evaluate the performance of a borate treatment chemical....