2000: First Laboratory Tests
The 2000 testing, which tested the early version of the TERM® Barrier membrane, conducted against the two dominant termite species in the US (Coptotermes formosanus and Reticulitermes flavipes) was successful. No termites penetrated the membrane, either at the membrane surface or at seams, where the adhesive sealant was exposed.
This initial test method is classified as a “no choice” test, which means that the termites had no other available source of food or moisture. Termites had to penetrate the membrane, or they would not have food or moisture.
2002: Southern Building Code (SBCCI) report on termite barrier
In 2002 the SBCCI issued Evaluation Report #2136, which listed Polyguard’s membrane for use as a foundation waterproofing and termite barrier.
The issuance of Report #2136 resulted in widespread installations of Polyguard TERM® Barrier membranes as a waterproofing and termite barrier, not only in the southeast, but in other parts of the U.S.
Based upon what we have learned since 2002 from ongoing development, we believe that a partial termite barrier, might only provide partial protection. TERM® Foundation Barriers will protect the foundation wall, but a number of other external surfaces of the structure (e.g. underslab, slab penetrations, bath traps, lower areas of exterior sheathing) may be vulnerable to subterranean termite penetration.
Note: Evaluation Report #2136 expired in 2008. Development of a new national ICC evaluation to replace and expand the scope of the 2002 evaluation is in process. The relevant ICC standard (AC 380 – Termite Physical Barriers) has been expanded to include Polyethylene Composite Barrier Laminates.
2003: Testing of TERM® Membrane against penetration by termiticides
This lab test followed ASTM F-2130 Standard Test Method for Measuring Repellency, Retention, and Penetration of Liquid Pesticide Formulation Through Protective Clothing Materials. The results showed no penetration of TERM® Membrane by any of the termiticides.
The reason for this pesticide resistance test is because much of today’s construction is done on land which was historically farmland. In previous decades, some extremely toxic pesticides with up to 50 years’ residual life were applied to cropland. If such farmland becomes a construction site, protection against penetration of pesticides may be necessary at the slab level.
2003 – 2006: TERM® Proof of concept testing
A Proof of Concept test, using treated and untreated wood billets, was installed at a College Station residence in 2003. This site had to be abandoned after October 2006, when the site became inaccessible due to landscaping changes. However, the site was evaluated after years 1,2, and 3. All wood billets treated with TERM® Membrane Sealant Barrier was undamaged (10.0 rating). Only small remnants remained of the untreated wood billets. (0.0 rating).
2004: Construction of prototype home with full TERM® building envelope
In March 2004, a 2172 ft2 residence was constructed which incorporated a full TERM® membrane building envelope (TERM® Underslab, Flashing, Seam, and Window Barriers). The structure was not a documented research project. However we do have anecdotal evidence from the owner, who tells us; “The only insects which have gotten in the house have come down the chimney or through the door”.
Another anecdotal comment from the owner; “Our house is the only one on the street which has not had the slab crack”. This region of Texas has very expansive clay soils.
We believe that the reason this home’s slab has not cracked is because the TERM® Underslab Barrier, in addition to acting as an insect and pest barrier, is a full coverage waterproofing barrier. Clay soil underneath the home has expanded during wet periods, but the soil’s ability to dry and shrink during dry periods is restricted by the waterproofing barrier covering. Wet soil underneath slabs dries out by vapor drive “breathing” through the concrete slab. In the case of this prototype home, evaporation through the concrete slab has been prevented.
2005: TERM® Particle Barrier reduced to practice and properties refined
Research on “particle barriers” as termite barriers was first published in 1957 by Eberling and Pence of the University of California at Berkeley. The researchers demonstrated that exactly sized hard stone particles of approximately ASTM 8,10, and 12 sieve sizes created a barrier which subterranean termites were unable to penetrate.
Particle barrier research was developed further and reduced to practice by Tamashiro, Yates, and Ebesu of the University of Hawaii. As a result of the work of these and researchers in Australia and elsewhere, the use of stone particle termite barriers came into widespread use in Hawaii, Australia, and other countries around the Pacific.
Stone particle barriers have not come into use in the mainland United States, however. One reason for this failure is that the cost of shipping basaltic rock particles from Hawaii, or granite rock particles from Australia, is prohibitive. Unfortunately, on the mainland, the use of “sand” particles, or “sandblasting sand” particles, or “16 grit” sand has been widely and incorrectly recommended on internet sources as a termite barrier.
This internet misinformation has been shown to be flawed by a number of mainland researchers, led by a study published in 1991 by Su, Schreffran, and Ban of the University of Florida. This study showed that particle sizes of 8, 10, and 12 were effective barriers against both Coptotermes formosanus and Reticulitermes flavipes.
The graphs below chart the study results to show that sizes smaller than 12 began to lose effectiveness. Size 16 as an example was ineffective against Coptotermes formosanus and only partially effective against Reticulitermes flavipes.
University and professional development of mainland U.S. sources; refinement of property requirements
In 2005, following bioassays by Texas A&M researchers, a TERM® particle barrier source meeting the size and hardness properties proven by previous research was reduced to practice in 15 Texas homes. Homes included in this initial set of field trials were all infested by subterranean termites. After installation, the homes were inspected annually for 5 years. For the duration of this Texas field test, none of these homes were reinfested.
Additional research by Texas A&M entomology scientists resulted in the refinement of physical property requirements, defining several additional properties which impact the efficacy of particle barriers.
TERM® Particle Barrier installed at exposed
perimeter of an Austin TX credit union
2005 – 2011: Long term field trials of TERM® Sealant / Membrane Barriers
Wood samples protected with TERM® Barrier were buried in four areas of known termite activity in southeast Texas. Two of these areas had active Coptotermes formosanus and two of the areas had active Reticulitermes flavipes. Over the five-year study, samples protected with the sealant barrier consistently rated a 10 (no damage). Wood samples that were unprotected by the TERM® Barrier were destroyed (rating 0) by year 3 in all but one test site. Samples at the remaining test site were seen to be destroyed in the year 5 inspection.
2012 – present: Testing expanded to other major universities, and to other pest types
While testing of subterranean termite barriers continues, testing has been expanded:
- Additional barrier materials such as screening are being tested.
- Additional laboratories are being utilized. Texas A&M continues in TERM® testing, and laboratories such as Louisiana State University, University of Florida, University of Georgia, and the City of New Orleans Mosquito, Termite, and Rodent Laboratory have been involved in TERM® Barrier testing.
- Additional pests are being tested. Subterranean termites are considered to be the most invasive and damaging pest, but numerous other pests impact health and comfort within a structure. Some of these are invasive, such as fire ants and rodents. Others, such as ants, cockroaches, scorpions, and snakes, are simply foraging – they are non-destructively searching for an opening where they can reach food, moisture, warmth, or shelter. These foraging pests, between them, enter at every gap in the structure.
- TERM® Sealants and Membranes start with the same building envelope waterproofing, moisture proofing, and energy sealing materials as those evolved by Polyguard Products since the middle of the 20th century. Polyguard has a long record of protecting major structures such as hospitals, hotels, stadiums, subway systems, and schools nationwide [...more].