Basaltic Termite Barrier

Until now, the only effective barrier against the Formosan was formed by long-lasting chemicals like chlordane. Such Chemicals - Because they represent potential hazards to humans and to the environment - are not now available.

Professor Tamashiro found that particles of a very hard substance with specific size, and shape and weight characteristics could form an effective barrier. Exhaustive tests indicated that Basaltic Barrier has all those characteristics… and is readily available. Further tests were undertaken to determine its effectiveness against the Formosan.

The field tests were spectacularly successful. The Formosan could not penetrate the barrier because the particles were to large and heavy to carry, too small to create gaps through which to penetrate, and too hard to chew.

For the first time in history, a safe, durable, cost-effective barrier against the Formosan Subterranean Termite has been Developed.

HC&D, LLC-through a unique process developed to produce manufactured sand for its concrete products-now supplies the basaltic barrier with the specifically required size, shape and weight.


BTB Specifications 
Rock TypeBasalt
Specific Gravity (ASTM C128)2.7 to 2.8
SiO2, %(ASTM C289), min.45
L.A. Abrasion, % loss, max

500 revolutions (ASTM C131)
Mohrs Hardness Scale5 to 6
Material Gradation 
Sieve Size%passing
No. 4 (4.75mm)100
No. 8 (2.36mm)95-100
No. 10 (2.00mm)75-95
No. 12 (1,70mm)35-50
No. 16 (1.18mm)0-10


The Materials and Methods of Termite Control

Soil Type: The soil beneath floor slabs must be firm and stable. One of the factors affecting this stability is the composition of the soil, particularly the clay content. Clay soils expand when they become wet; that expansion can cause slab "heaving" and foundation cracking that looks very much like settlement cracking. The common "black clay", which is commonly found in valley floors and at the transition between valleys and the adjacent hillsides, is frequently expansive. Where expansive soils are suspected, the advice of a structural or soils engineer should be sought.

Termite Protection 

for your home

Soil Compaction: A second consideration in assuring the stability of the soil beneath the slab is the compaction of the soil. The soil must be compacted to a density which is permanently stable under the loads imposed. Any movement of the soil beneath the slab will resulting cracking of the slab or in voids beneath the slab. Either condition can allow termite entry. This is particularly a problem where fill soil has been added to raise the grade or a portion of the slab, such as when the uphill portion of a sloping site is excavated and the soil used to build up the lower portion. Standard soils engineering methods require placing the fill material in "lifts" of layers about 12"deep, compacting each layer before adding the next.

Base Course: The purpose of the base course is to provide a firm and even base on which to pour the slab. The material should be crushed rock, S4C of Base Course. In areas of high ground water, use 3B-fine (#67) which is a capillary barrier.

Vapor Barrier: The installation of a vapor barrier will impede the migration of moisture or water vapor from the ground beneath the slab to the floor. In order for the vapor barrier to function it must be unbroken and unpunctured. If the barrier is not tight, blistering of resilient flooring, staining of wood flooring, and damp carpeting can result. 6 mil polyethylene sheet is the most commonly 

used material.

Sand Course: Placing a 1" to 2" layer of sand on top of the vapor barrier will help to disburse excess water from the bottom side of the slab at approximately the same rate as moisture evaporates form the top surface, during curing. This maintains an even moisture content at the top and bottom of the slab, eliminating curling and reducing cracking. The use of sand in this location, however, may allow access by subterranean termites to cracks or penetrations that might occur in the slab, should any termites get past the primary BTB barrier. Using BTB instead of sand provides the same function for the concrete curing and termite protection as well./p>

Concrete for floor slabs: Use concrete with a minimum strength of 3000psi. good concreting practices in placement, finishing and curing should be employed to minimize cracking.

Footing Drains: Perforated drain pipe should be placed at the lowest part of the excavation and sloped at 1/8" per foot to "daylight". The opening should be protected from blockage.


The Materials and Methods of Termite Control

Reinforcing for floor slabs: Most concrete floor slabs are reinforced with a bar-type reinforcing in the footings and a light-weight welded wire mesh in the "field". Use "chairs" to hold the mesh in the proper position, in the middle 1/3 of the slab. Adding of polypropylene reinforced fibers to the concrete mix will significantly reduce plastic shrinkage cracking.

Typical Slab Egde
Typical Slab Egde
Garage or Lanai Slab Edge to
Garage or Lanai Slab Edge to

House Slab
Driveway Slab to Garage Slab
Driveway Slab to Garage Slab

Control Joints in the floor: To minimize random shrinkage cracks from dying, control joints should be placed 10' to 12' on center in both directions, for a 4" thick slab. A saw-cut ¼ to 1/3 of the slab thickness should be made as soon as the concrete has hardened enough to make the cuts with-out leaving ragged edges.

Curing of the floor slabs: One of the most common causes of cracking of concrete slabs is improper curing, where the concrete loses moisture at a rate faster then the chemical bonding (hydration) occurs. Covering the surface of the slab with a polyethylene sheet after spraying it lightly with water is one of the most effective ways curing methods. The covering should be maintained for at least 3 days. The use of spray-applied curing compounds is the simplest and may also be effective.

Waterproofing Membranes on retaining walls: Where finished spaces are separated from the soil by retaining walls, it is important to provide a good water proofing membrane on the soil side of the retaining wall. Where water penetrates an inadequate membrane, damage to the finished surfaces is likely. In addition, termites can use the wet wall areas as their source of moisture, leading to serious infestation. Cold-applied asphalt compounds, even when reinforced with glass-fiber fabric, are not usually adequate to provide the protection and durability necessary. Some membrane materials which provide good waterproofing also provide space between the waterproofing and the structural wall where the termites can travel unobserved. From a termite protection standpoint, the waterproofing membrane must be both an effective water barrier and tightly adhered to the substrate. Where BTB is installed on the soil side of the retaining wall, no protection board is necessary over the waterproofing membrane as the size and shape of the BTB granules does not present a threat to the integrity of membrane, assuming reasonable care is taken by the installers. Most protection boards are a food source for termites and are, therefore undesirable.

Concrete Vs. CMU for treating and foundation walls: Concrete masonry units (CMU) are commonly used for retaining and foundation walls. Small spaces in the joints between the blocks and the grout used to fill in the hollow cores and surround the reinforcing steel, allow adequate space for termite movement. While the termites cannot damage the concrete blocks, the spaces within the blocks provide concealed pathways from the point of entry to wood, there they can do extensive damage. Well placed poured-in-place concrete does not provide these potential pathways.

Separator Strips: Where one slab abuts another at an expansion joint or where a floor slab abuts a retaining wall, a separator strip should be installed to allow expansion, contraction, and/or differential vertical movement. Asphalt-saturated fiber strips have been used in that condition. Unfortunately, termites can eat the fiber material, leading to concealed infestation of adjacent wood components, occasionally wood, even treated wood, has been used; termites can eat through that as well. While no material is currently acknowledged as ideal for that condition, two materials are promising. One is borate treated EPS foam, cut to a 3/8" to ½" thickness. The second is 60 mil SBS-modified asphaltic sheet (Jiffy Seal, Quaker 701, Bituthane, etc.). BTB should be placed beneath the joint, however, in any case.

Vertical Containment Barrier: When installing BTB against a retaining wall or at the edge of a deep footing, a "dam" can be created to limit the quantity of BTB needed, to control the width of the BTB layer, and to keep soil out of the BTB. Corrugated fiberglass or aluminum roofing sheets are inexpensive, readily available, easy to cut and handle, and will not decay or attract termites while remaining permanently buried next to the building. The sheets should be overlapped a minimum of 4" or 2 corrugations, creating a barrier which will minimize the future penetrations of roots into the BTB. The Corrugated sheets should be placed a minimum of 4" from the face of the wall, the house side filled with BTB and soil back fill on the other. The BTB and the back fill should be placed in 12" lifts, with each lift compacted.

Bio-Barrier: Root penetration into the BTB is a potential by-pass route for termites thru the BTB, as the termites can eat their way along the roots. One way to avoid this, is to install a root barrier at the BTB to soil interface, particularly for the top 12" to 18" of soil. "BioBarrier" is a geotextile fabric impregnated with time-release nodules of a root growth inhibitor.

Wood Treatment for framing lumber: Several chemicals are available for treating wood to resist termite infestation. While the effectiveness of the chemicals and the availability of the treated wood varies, the critical requirements are 1) that the wood is pressure treated, not brushed, dipped or sprayed, and 2) that the treatment is done to an accepted standard. The American Wood Preservers Association (AWPA) publishes the most widely accepted standards.


Problem areas/difficult conditions

  1. Exterior Wall Veneers of stucco, synthetic plaster, marble, stone, wood or pressed wood sidings sometimes improperly extend into the soil. A minimum separation of at least four inches must be provided between the bottom of the siding and the soil. The termites will then be forced to build their mud tunnels over the slab and will, therefore, be visible for detection and treatment.

  2. Masonry (hollow tile) retaining walls supporting buildings can provide a conduit for termite infiltration. Even though the wall may be grouted, the subterranean termites can use small spaces within the masonry wall, waterproofing, and backfill to gain entrance into a structure.

  3. Beneath the bathtub, where the drain from the bathtub penetrates the floor slab, a hole 6" wide and 12" long commonly occurs. These openings are a common termite entry point and have led to severe infestations. Because of the location, this condition is inaccessible for inspection and pesticide treatment. The opening should be filled with BTB after installation of the bathtub drain plumbing and access panels provided to allow periodic inspection.

    Slab on Retaining Wall

    Slab on Retaining Wall
    Retaining Wall with Footing

    Retaining Wall 

    with Footing
    Retaining Wall with Thickened Slab Edge

    Retaining Wall 

    with Thickened 

    Slab Edge
  4. Cracks and cold joints in concrete slabs can serve as entry pathways for subterranean termites. Installing BTB as a base course will permanently prevent the Formosan termite from accessing the underside of the concrete slab, and from penetrating the cracks which may occur at a later time.

  5. Plumbing penetrations through concrete slabs are common entrance points for subterranean termites. This problem has become even more serious with the recent practice of installing plastic sleeves around copper pipes, as the sleeves can shield the termites from termiticide treatment and provide a bypass thru the BTB, facilitating termite entry. A tight wrap of plastic tape or a spray application of epoxy will provide equal protection and is preferred. If the sleeves or wrap are to be installed, the extent must be limited to only that portion of the pipe which is actually enclosed in the concrete. Do not extend the sleeves into of thru the BTB.

  6. The use of lumber which is not pressure treated for termite resistance is probably the single termite protection problem. Use of untreated lumber will very likely result in extensive damage by the Formosan termite. Three types of treatment are most commonly available: ACZA ("Chemonite"), CCA ("Wolman" or "Osmose"), and borate ("HI-Bor"). ACQ ("Preserve") is a new treatment may become available soon. Tribucide is available for wood that is to be finished with a light or natural semi-transparent stain.

  7. Exterior Paneling composed of pressed wood materials is prone to degradation by water and attacked by Formosan termites. If not well maintained, it can retain moisture, providing a water and food source for the termites.

  8. Wood shingle roofs are susceptible to termite attack, especially if they are not maintained well to keep them water resistant. 

    Renovation Detail for Added Pipe

    Renovation Detail for Added Pipe
    Remedial Detail @ Bathtub Blockout

    Remedial Detail @ Bathtub Blockout
    Remedial Detail for Perimeter Protection

    Remedial Detail 

    for Perimeter Protection
  9. Galvanized sheet metal or roofing felt are sometimes used as termite shields or moisture barriers under wood sill plates attached to the top of CMU walls. In order for sheet metal to be effective as a termite barrier, the joint laps between adjacent sheets must be soldered, both edges of the flashing must be visible, and all holes around the anchor bolts and other penetrations sealed with solder epoxy. Roofing felt, while of some value as a moisture barrier, has little no resistance to termites and can serve as food for subterranean termites. Severe termite infestations can occur if the nature and uses of these materials is not well understood.

  10. The crawl space beneath post-on-pier homes should be well ventilated to avoid the accumulation of moisture. This is particularly important if the area is fully enclosed by CMU perimeter walls. Adequate ventilation must be provided.

Steps you can take to protect your house

Your home is probably the largest single investment you will make. Here are some helpful hints to help reduce your exposure to subterranean termites and the consequent repair costs.

  1. Formosan termite adults (winged individuals) swarm on windless nights during the early summer months each year. When swarming starts, turn your lights off to reduce the attractiveness of your home. If many swarmers appear inside your home, look for flight slits (flit-like openings in the wallboard or parallel to the grain in wood) to determine if there is an infestation inside your home. If you find wingless tandem pairs of adults, kill them, since they are future kings and queens of new colonies.

  2. Inspect in and around your home for evidence of infestation ounce every three months or so. Look for mud tunnels on the sides of your foundation walls, sagging or warping structural members, hollowed wood, spongy wooden floors, flights slits, etc.
Ant or Termite?

Ant or Termite?
  1. Plants should be kept approximately two feet away from the building perimeter. This will keep moisture away from the building and allow accessibility for inspections. Shrubbery and trees should be pruned so as to not shield the home from sunlight and drying.


Interior Thickened Slab

Interior Thickened Slab
Interior Expansion Joint

Interior Expansion Joint
Subslab Drain Piping

Subslab Drain Piping
Subslab Water Piping

Subslab Water Piping


  1. Gutters and downspouts should drain away from the house. Extending the downspout four to five feet away from your house will help greatly.

  2. Sprinkler heads should be selected and directed so that the spray does not wet the building, the heads kept 3' or so from the building and repaired if leaking. Consider reducing the frequency of watering.

  3. Leaking hose bibbs supply water which can attract termites. Maintain the washers to 

    prevent dripping.

  4. Improper grading can lead to subterranean termite attack. Make sure that water drains away from the structure; a French drain or foundation drain may be necessary.

  5. Exposed decking should have good drainage and be treated to resist decay and termites.

  6. Wooden fence posts and planters are often in contact with the soil. Avoid all wood-to-soil contact, and avoid contact by fences and planters with the main structure, since they can serve as excellent avenues for penetration by termite colonies.

  7. Remove any materials that are food for the Formosan termite from under and around the structure. Such materials include form lumber, wood stakes, plant stumps, and roots, carpentry scraps, wooden materials stored under or around the home, stored paper products, and all other materials which contain cellulose.

  8. Plastic sheets installed below cinder or coral chips around the perimeter of your home will create a moisture problem due to water condensation on the bottom side of the plastic. Instead of plastic sheeting, use the special fabric that has been designed to prevent weed growth while providing aeration, which is available from local lawn and garden shops.

  9. Wood chips should not be used as ground cover or mulch around or near the perimeter of your house since the wood can serve as food for termites and may attract them.