termite protection beneath concrete s...

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Author Message Robin E. Snyder Senior Member Username: robin Post Number: 521 Registered: 08-2004 Posted on Monday, March 24, 2014 - 05:07 pm:    I have had this issue come up twice in the past week... typical termite treatment is around the foundations and perimeters. In locations with wood floors (think, large gyms), the termites are coming up through the concrete slab joints. Any recommendations on how to protect beneath slabs (in both new and existing construction)? I had one client custom design a system that was like an irrigation drip system that ran under the slab. Any more "accepted" and tested ideas are welcome! Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 652 Registered: 10-2007 Posted on Monday, March 24, 2014 - 05:37 pm:    Obviously the slab joints have opened enough to allow the termites to pass through. I will suggest that there may also be other cracks in the slab that are big enough. One way to solve this problem for new construction is to control the crack size and the way to do that is to add reinforcing to the slab that is continuous through the joints. I would expect that if you had 0.5% reinforcing steel each way in the slab the crack size would be acceptably small. Individuals will complain about what they believe to be unnecessary reinforcing in the slab but consider the cost of other strategies. Wire mesh will not be effective in controlling the cracks. Since the slab will be covered by the wood floor nobody will notice any cracks. The existing floors likely have cracks that are not at the concrete slab joints so why be concerned with small cracks. In any case the tight cracks associated with a well reinforced slab will likely be acceptable to most individuals. Wayne Yancey Senior Member Username: wayne_yancey Post Number: 636 Registered: 01-2008 Posted on Tuesday, March 25, 2014 - 10:29 am:    Robin, For existing structures plagued with termites my experience goes back to my time in Oahu HI. Tenting and gassing the structure was the method of choice. This is, or at least was, a mandatory step when selling a house in HI. For what it is worth, for new home and building construction in HI the U of H recommends basalt rock under the slabs. Basalt is a common volcanic rock. When small pieces of basaltic rock are compacted together, they can form a barrier that can be used to help prevent termites from entering your home or building. How Does a Basaltic Termite Barrier Work? Similar to a sand termite barrier, a basaltic termite barrier (BTB) is made of basalt particles that are large enough that termites cannot move them and small enough to fill gaps so termites cannot crawl between them. Basalt is crushed to particles that measure 1.6 to 2.5 millimeters to be used for a BTB. When installed pre-construction, a BTB is layered several inches thick below and around the foundation of a home or building. It also can be installed around the slab of an existing home. BTB is a chemical-free termite barrier. It does not control a termite population; it simply helps block a termites’ access to a home or building. Installation and Maintenance for Basaltic Termite Barriers Particle barriers, like BTB, are not recommended for all homes and buildings. Installation can be difficult and expensive. Particle barriers work best in climates where the soil is stable and compacted. The soil surface should be smooth below the BTB and not readily expandable. Soils that expand when wet are more likely to create gaps in particle barriers. To maintain consistent size of particles in the barrier, construction crews must take care not to mix the barrier particles with soil during installation. The BTB will not be effective if it is contaminated with dirt or construction dust. Consult with local pest professional on tips to avoid damaging the BTB with future construction or landscaping. Even roots from landscape plants can cause problems. If roots grow into the BTB, termites can eat along the roots and find their way through the barrier. Some basaltic termite barriers are installed with Biobarrier, which prevents root penetration. Now for the bad news. Basaltic termite barriers are common in Hawaii, where basalt is plentiful. It is cost-prohibitive to transport basalt to the continental U.S. when other preventative measures can be used to provide similar results. I hope this provides some information or gets the creative juices flowing to move foward with your issue. Wayne Wayne Yancey Senior Member Username: wayne_yancey Post Number: 637 Registered: 01-2008 Posted on Tuesday, March 25, 2014 - 10:31 am:    Robin, Here is website I found that may provide more information. This is my source for some of the information in my previous post. http://www.termites.com/control/barriers/termite-sand-barrier/ Lynn Javoroski FCSI CCS LEED® AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1784 Registered: 07-2002 Posted on Tuesday, March 25, 2014 - 12:37 pm:    We've used diatomaceous earth for general insect control, filling CMU cavities as well as perimeter installation. I'm not sure it would work with termites. It works by basically (squeamish alert) shredding their bodies on the sharp surfaces. "Insecto" is one product; Nitron Industries, Inc., and Planet Natural are others we've spec'd.