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.
|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 Scale||5 to 6|
|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.|
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
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
Garage or Lanai Slab Edge to
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
- 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
- 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.
- 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
- 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.
- 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.
- 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
- 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.
- Wood shingle roofs are susceptible
to termite attack, especially if they are not maintained well
to keep them water resistant.
- 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.
- 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.
- Gutters and downspouts should drain away
from the house. Extending the downspout four to five feet away
from your house will help greatly.
- 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.
- Leaking hose bibbs supply water which
can attract termites. Maintain the washers to
- 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.
- Exposed decking should have good drainage
and be treated to resist decay and termites.
- 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
- 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
- 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.
- 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.