Termite Control - Alternative Measures Physical barriers rather than termiticides  Termite control traditionally is performed through soil chemical treatments that act as barriers between subterranean termites and the house. Other barrier control methods that don't rely on termiticides as the primary deterrent are called physical barriers. Physical barriers can either isolate particularly vulnerable elements of a house such as penetrations through foundations and slabs or protect the entire perimeter of the foundation. Proper placement and installation of physical barriers can provide termite protection for houses with little to no risk of pesticide exposure to the occupants.
Physical barriers commercially available in the United States include aggregate, stainless steel mesh, and plastic impregnated with a termiticide. Aggregate barriers, sometimes called basaltic or sand barriers, are comprised of soil particles that are too heavy or large for termites to move and yet small enough so that spaces between aggregates are too small to pass through. Termites move soil by using their mouth rather than by digging with their legs or bodies, and aggregate in the 1 to 3-mm range is too large for them to manage. A Basaltic Termite Barrier (BTB) consists of basalt aggregate in the #4 to #16 square mesh opening range (4.75mm to 1.18mm). Aggregate barriers are placed between soil and vulnerable components of a house, such as the slab or foundation. Stainless steel mesh barriers have a screen opening that is too small for termites to pass through and too durable for them to shear. In addition, they will not corrode from environmental exposure. Mesh barriers have mesh openings of 0.66 mm x 0.45 mm and come in 47.24 in. by 100 ft. rolls. Mesh barriers can be applied over potential entry points into the foundation, such as service pipe penetrations, control joints, brick or block piers, etc. The mesh is bonded to the cement or masonry foundation using bonding cement or epoxy resin. Stainless steel clamps are used to fasten the mesh to pipes. Plastic barrier systems are designed to be installed around pipes and electrical conduit extending through slab foundations. The system also includes a tub trap barrier for the tub drain penetration through a slab. A polyethylene shell sandwiching a core of termiticide forms the plastic barrier system. 
For the U.S., aggregate barriers are commercially available in Hawaii, only. TermiMesh and Impasse Termite Blocker are found in most areas of the country where termites are a substantial problem. Success of termite barriers depends primarily on their proper placement and installation. Unlike soil termiticides and termite baits, termite populations are not reduced using physical barriers. Aggregate barrier installation requires care so that bridges are not created through the barrier by roots, soil disturbances, etc. In addition, the aggregate barrier should remain available for periodic inspection.
Not Applicable
Not Applicable
As of 2004, aggregate barriers were not commercially available in the United States, outside of Hawaii. Therefore, code approval has not been sought in states other than Hawaii. Australia approves the use of aggregate barriers, and has a product called GranitGard that meets the Australian Building Code and has a history of over ten years. TermiMesh has an evaluation report that states it conforms with, or is a suitable substitute for, termite protection stipulated in the Standard Building Code, the International One and Two Family Dwelling Code, or supplements thereto. The Impasse Termite Blocker has been registered in over 30 states. It is not intended as a stand-alone termite control system, but as a supplement to conventional termite control systems. Therefore, code acceptance should not be an issue for states where the system is registered.
Not Applicable
Aggregate barriers are installed between the soil and the foundation, slab, or other vulnerable spots in the house perimeter. The building design and site soil characteristics determine how and where aggregate barriers are placed, but the strategy is to block access for termites residing in the soil to the foundation or utility penetrations. Care must be taken that the barrier is not breached by trenching, mulching, plant roots, or other site disturbances. A mesh barrier is installed around the perimeter of a home and around utility penetrations or expansion joints. Installation shall be accomplished only through accredited installers - typically associated with a pest control operation. Penetrations are treated by fashioning a collar around the utility line and clamping the mesh to the utility. Other installations include under slab, in cavity walls, cold-joint installation between structures, over concrete masonry units, and around timber post supported structures. Plastic termite barriers are also installed around utility penetrations through slabs and foundations using clamps. This process is performed prior to the pouring of the slab, and so concrete encases the entire assembly. This system prevents termite entrance through concrete shrinkage cracks, or gaps caused by utility vibration. Termite barriers are not intended as a stand-alone termite control system, but are designed to complement chemical or bait termite control measures. Certified contractors in the pest control field should install plastic termite barrier systems.
Not Applicable
Barrier termite control systems typically cost more than chemically based termite control measures. Most systems can be used in combination with chemical control measures. For situations where chemical protection is not practical or desired, such as sites with high water tables, or homeowners with severe chemical sensitivities, properly installed barriers can act as an effective termite control option. In addition, some soils or structure designs are particularly difficult to treat with soil termiticides, so the use of termite barriers provides additional protection. Once installed properly, reapplications of the physical barriers are unnecessary, unlike chemical control measures. Costs of barrier systems are dependent upon the design and size of the home, the proximity to a certified applicator, and the system used. For mesh barriers and plastic termite blockers, the number of penetrations greatly influences the price. | 
