A novel chemical barrier system, KORDON® TMB, for the protection of buildings against subterranean termites using a synthetic matrix as carrier for the chemical
M Lenz, P Morrow, S Runko
Kordon TMB is a new chemical barrier system for installation beneath concrete slab-on-ground constructions using a matrix other than soil as carrier for the termiticide. The product consists of a synthetic foraminous web (blanket) carrying the synthetic pyrethroid deltamethrin. The blanket is laminated on the upper side to a standard 0.2mm thick moisture vapour membrane of low density polyethylene (LDPE) and on the other side to a sheet of black 0.05mm UV-stabilised LDPE. Installation of the barrier follows existing building practice of setting down and sealing the vapour barrier, as required, during site preparation for building. Results of the evaluation of component materials and key features of the Kordon TMB system, which has been ongoing for the past eight years, are briefly discussed in this paper.
Experiments simulated the use of treated webbing with or without LDPE under concrete slabs at sites near Griffith (New South Wales) in a semi-arid part of eastern Australia and near Darwin (Northern Territory) in the wet/dry tropics of northern Australia. In these trials timber has been protected from subterranean termite attack for more than seven to eight years at rates of 0.25 -2.50 g/m2 deltamethrin.
In another series of studies, samples of wood protected by the webbing with LDPE were exposed to termites using a below-ground exposure method. To date, these trials have demonstrated successful protection of timber from termite attack for periods of six months to two years for rates from 0.01 - 1.00g/m2 deltamethrin.
Laboratory studies have been conducted to simulate the Kordon TMB seals around service penetrations through the concrete slab. The first trial was conducted at incubation temperatures optimal to termite requirements, while a second series investigated the effectiveness of seals at lower temperatures more closely resembling conditions under a concrete slab.
Based primarily on this work, Kordon TMB has been developed in Australia for approval by regulators.