Author, Cassie Krejci, Ph.D.
Hello and welcome to another week of the TERM Barrier System blog series! Week 6
This week I would like to take a step back in time and write about the origin of termite barriers. The TERM® Barrier System is founded on the concept of using physical and mechanical devices to exclude termites without the use of pesticides, but from where did the idea arise?
In previous blogs, we have talked a lot about integrated pest management (IPM). One pillar of IPM is the use of physical and mechanical devices to control the target organism, such as a termite, in a balanced approach.
Termite particle barrier research originated with Dr. Walter Ebeling in 1957 at the University of California, Berkeley. Dr. Ebeling studied the penetration of subterranean termites through sand and cinder barriers of measured particle sizes. Effective substrates for stopping termites were as follows:
B. 10-16 mesh sand *untamped*
C. 6-16 mesh sand *tamped*
D. 10-16 crush volcanic cinders
Research has continued since the inaugural study by Dr. Ebeling to arrive at many conclusions related to particle size. However, in 2013, Keefer et al. collaborated the expertise of entomologists and engineers to identify specific characteristics that made particle barriers effective against tunneling termites.
Particle size combinations of 8, 10, and 12 mesh were most effective.
Particle hardness should be measured & scored as ≥6 on the Moh’s Hardness Scale.
Particle angularity should measure 2700+ as determined by the Aggregate Image Measurement System.
Interstitial space between particles should include 35-45% voids as determined by a displacement test.
There are many scientific articles that have been published between the two articles that I have written about today, including, but not limited to:
- Ebeling & Pence 1957
- Ebeling & Forbes 1988
- Su, Scheffrahn & Ban 1991
- Su and Scheffrahn 1992
- Lewis, Haverty, Carver, & Fouche 1996
- Yates, Grace & Reinhardt 2000
- Al-Rousan, Masad, Leslie & Spigelman 2005
- Keefer, Zollinger & Gold, 2013
While the history of termite barrier research focuses primarily on the use of aggregate stone to impede termite tunneling, Polyguard has improved our building materials to function as termite barriers, as well. Membranes traditionally used for waterproofing and vapor barriers have been upgraded by Polyguard as part of the TERM® Barrier System to exclude termites in addition to their normal function. Research on our membranes and sealants began in 2000 and continues to this day as we aim to improve pest exclusion.
Reports of independent research projects completed on TERM® Barrier System products may be found on our website.
For additional information on the TERM® Barrier System products, please feel free to email me at email@example.com.