Termites invade houses in their search for cellulosic foodstuffs. The damage to US properties is put at about $1 billion per annum. Various methods have been used to protect buildings from being infested with termites, and many more methods used to rid the buildings of termites once infested.
The market has historically been dominated by pre-construction intensive spray application of long residual pesticides on to a foundation soil surface prior to the laying of the concrete slab over a plastic sheet such as a Damp-Proof Membrane-DPM, vapor barrier, vapor retarder or the like. Such pesticides as organo-phosphates-eg chlorpyrifos, pyrethroids eg cypermethrin have been employed. More recently, products such as imidacloprid and fipronil have been employed. Other, more environmentally acceptable, methods of termite-proofing a dwelling place have also been developed such as establishing physical barriers to termite entry (eg stainless steel mesh underlays, thick paints, composite materials). These have usually not contained pesticides.
Baiting is another method to control termites. Bait stations are installed underground around the perimeter of the house, for example, every 10 to 20 feet and 2 feet out from the house. This method takes considerable time to eliminate a colony of up to one year. It relies upon individual termites feeding on the bait, and returning to the colony to pass the poison on to other members, killing a portion of the exposed colony. However, termites that are not attracted to the bait may seek out wood in the building to feed on.
Other technologies include the use as a barrier of manufactured plastic films or composite film sheets that incorporate a termiticide. Drawbacks with this concept include long (and therefore costly) installation times and difficulty with sealing effectively what are termed “ground penetrations”. These ground penetrations arise as a result of having to install piping (for water, heating, waste disposal) underground that rise up through the hardcore base of the building sub-structure and come into the building. Sealing these penetrations against termite entry is a key component of such systems and requires the careful installation of shaped polymer articles of the same composition. When carried out carefully by expert installation engineers, the whole barrier is extremely effective in preventing termite access to a house though the concrete sub-floor slab. However, unless sufficient care is taken, gaps or openings in joints would be inevitable, allowing for points of termite passage. This process is obviously time consuming and therefore expensive.
In many of these processes, the permeability to water of the formed film or coating and the release rate of the insecticide play decisive roles in the resistance and residual effectiveness of the barrier to wood-boring insect attack.
There exists a need for an easily installed pest resistant barrier that offers similar benefits of low environmental impact with long residual effectiveness against fungi, insects and representatives of the order acarina including termites, wood-boring ants, wood-boring insects and spiders.
USPTO Backgrounds
USPTO Backgrounds