Reticulitermes flavipes (Kollar), were introduced to the top of an arena with a divider of various crack widths. Termites were not able to pass through cracks ≤610 μm, and feed on the bottom of the arena. The minimum crack width permitting termites to pass was 711 μm for workers and larvae or 813 μm for soldiers. The percentage of termites passing through a crack increased as crack width increased from 711 to 5000 μm. For 5000 μm cracks that did not restrict access to the bottom filter paper about 74% of the termites passed through and consumed ∼40 mg filter paper. As crack size decreased to 711 μm only 35% of termites passed through, however, consumption of filter paper on the bottom (∼38 mg) did not significantly decrease. This suggests that any crack ≥711 μm would not limit termite damage in a structure. Head capsule dimensions (length, width, and depth) were measured for termites passing through various crack widths. As crack width increased, the maximum head capsule dimension of termites that passed through the crack also increased linearly. Depth of head capsule was best correlated with crack width that allowed termites to pass through it.

Termites often use plumbing penetrations of concrete slabs to enter a structure. Polyethylene and foam sleeves used to protect pipes from physical damage were found to protect termites from residual soil termiticide treatments. When pipe sleeves extended beyond the termiticide treatment, termites utilized the sleeves as a protected route through the termiticide-treated sand. However when pipe sleeves terminated within the termiticide treatment, termites failed to pass through the slab. Impasse™ Termite Blocker installed on pipes prevented termites from passing through the slab at pipe penetrations.

Building construction materials (2x4s, 5-ply plywood, and rigid foam board insulation) were exposed to termites for 8 wk and a method for measuring changes in thermal properties was developed by heating one surface and imaging the temperature on the opposite surface. Termites mainly tunneled into 2x4s penetrating the sample resulting in ∼35% increase in surface temperature (damaged vs. undamaged samples) despite a small amount of damage (6.7% consumed). Plywood damaged by termites (3.1% consumed), was the most thermally damaged with a temperature increase of 74% (damaged vs. undamaged samples). Insulation was significantly the most damaged with ∼12% of the material removed and a temperature increase of ∼27% (damaged vs. undamaged samples).

A heat transfer index was developed to compare thermal properties of termite damaged building construction materials (2x4 and 2x6 pine lumber, 5 ply plywood, T1-11 siding, oriented strandboard, extruded polystyrene, and polyisocyanurate insulation). Termite damaged materials had higher heat transfer indices than undamaged materials The heat transfer index of damaged 2x4 and 2x6 lumber was 37% higher than damaged 5 ply plywood and T1-11 siding: therefore the siding materials were more thermally resistant. As would be expected the insulation materials had lower heat transfer index values than the wood materials. Termite damaged polyisocyanurate was 68% more conductive than the damaged expanded polystyrene insulation.