Basalt is a common volcanic rock. When small pieces of basaltic rock are compacted together, they can form a barrier that can be used to help prevent termites from entering your home.
How Does a Basaltic Termite Barrier Work?
Similar to a sand termite barrier, a basaltic termite barrier (BTB) is made of basalt particles that are large enough that termites cannot move them and small enough to fill gaps so termites cannot crawl between them. Basalt is crushed to particles that measure 1.6 to 2.5 millimeters to be used for a BTB.
When installed pre-construction, a BTB is layered several inches thick below and around the foundation of a home. It also can be installed around the slab of an existing home.
BTB is a chemical-free termite barrier. It does not control a termite population; it simply helps block a termites’ access to a home.
Installation and Maintenance for Basaltic Termite Barriers
Particle barriers, like BTB, are not recommended for all homes. Installation can be difficult and expensive. Particle barriers work best in climates where the soil is stable and compacted. The soil surface should be smooth below the BTB and not readily expandable. Soils that expand when wet are more likely to create gaps in particle barriers.
To maintain consistent size of particles in the barrier, construction crews must take care not to mix the barrier particles with soil during installation. The BTB will not be effective if it is contaminated with dirt or construction dust.
Homeowners should consult with their pest professional on tips to avoid damaging the BTB with future construction or landscaping. Even roots from landscape plants can cause problems. If roots grow into the BTB, termites can eat along the roots and find their way through the barrier. Some basaltic termite barriers are installed with Biobarrier, which prevents root penetration.
Basaltic termite barriers are common in Hawaii, where basalt is plentiful. It is cost-prohibitive to transport basalt to the continental U.S. when other preventative measures can be used to provide similar results.