Termite barrier

Termite barriers are materials that have been specifically designed to prevent subterranean termites from gaining access to a structure. Termite barriers are free of pesticides and act as physical and mechanical impediments to termite foraging activity. Development of physical barriers to effectively exclude subterranean termites have made it possible to add new dimensions to integrated pest management strategies for both new and existing structures. Termite barriers are unique in that, since they contain no pesticides, they are classified as devices by the United States Environmental Protection Agency.

Particle Barriers

Particulate termite barriers have been widely and successfully used in across the world since the 1980s. However, they only became commercially available in the mainland United States in 2003. The principle behind particle barriers has been well researched by Ebeling and Pence (1957),^[1] Su et al. (1991),^[2] Su and Scheffrahn (1992),^[3] Yates et al. (2003), and Keefer et al. (2013).^[4] One type of particle barrier is the basaltic termite barrier. These are used in Hawaii and Australia and are installed beneath the foundation of a structure. Basalt is volcanic rock, common to these areas, and is compacted to create a physical barrier for termites. Research with particle barriers for the mainland United States was initiated at Texas A&M University in 2003. Various particle characteristics were evaluated, including size, angularity, and interstitial space between particles.^[4] This material is generally installed on the perimeter of a home or structure in a wedge formation that measures 4 inches across and 5 inches down, directly against the foundation. Aggregate barriers have also shown success when installed in bath traps or slab leave-outs. During construction and after the foundation is poured, cardboard and other debris is removed from bath trap areas and the particle barrier is installed. Application of this material protects the structure from termite intrusion in a vulnerable area.

Membranes

Termite membrane barriers consist of elastomeric sealants adhered to a high-strength backing. When included in the building envelope, membrane barriers may act as waterproofing, air barrier, and vapor barrier, as well. Applications for termite membranes include on insulated concrete forms (ICF), under sill plates and flooring, and as window, door, and base flashings, among others. Termite membrane barriers are pesticide-free and act as a physical barrier to termite intrusion. Most termite membranes must be implemented during the construction process.

Sealants

Termite sealant materials are the basic component of termite membranes described above. Sealants are elastomeric, meaning they move with the structure without tearing, and are available in a caulk or spreadable formulation. When caulked around a plumbing penetration in a structure, termite sealant barriers adhere to both the pipe and the concrete. As the structure moves during settling or due to expansive soils, the sealant barrier material maintains a barrier that is impenetrable by termites and other urban pests.

Stainless Steel Screens

Screens with apertures small enough to block termites were developed in Australia and have widely used in the United States, mostly for plumbing penetrations, since the 1990s. One of the early uses of screens for pest exclusion was the implementation of screen doors and window coverings. Screens are required by building codes at vent openings. To exclude rats, screen openings must be ½” (13.7 mm) or smaller. To exclude mice, a screen aperture size of ¼” or smaller is required. Most insects can be excluded with screens measuring 1/16” (1.59mm) in aperture size, but to effectively exclude subterranean termites, required screen apertures measure 1/55” (0.46 mm).^[5] Application areas for screens in the building envelope include weep holes, soffits, gable and ridge vents, among others.

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