FR2652602A1 - Barrier material against termites and its application especially to the preparation of continuous layers against termites and barriers against termites - Google Patents

Abstract

A barrier against termites which is particularly suitable for the protection of buildings comprising a grid (10) consisting of a material which resists rupture in the environment of use and which is resistant to secretions deposited by termites, such as stainless steel, and which is also sufficiently hard not to be attacked by termites, with a hardness which, for example, is not less than approximately Shore D70. The pores (15) in the grid (10) are sized so that the maximum linear dimension of the pores (15) in any direction is smaller than the maximum linear dimension of the cross-section of the head of the species of termites to be controlled.

Description

 The present invention relates to the fight against termites, in connection with buildings or other structures, and in particular the implementation of such a fight without using harmful chemicals.

 The most commonly used procedure to provide a barrier against termite access to buildings or other supported structures in or on the ground is to saturate the soil below or near the structure using of appropriate chemicals, in order to kill all the tarnishes that exist there, and to provide in the soil a residue of chiaic products which may be opposed for many years to the passage of termites through it towards the structure. , in patent descriptions, to make a mat of fibrous or absorbent material to spread under the foundations of a b8tinent, the fibrous or porous material being saturated with an appropriate chemical, or containing such a product, in order to kill the termites trying to cross it. Reference is made to the Australian patents published: N 85176/82, 11412/83, 16980/83 and 21934/84.

 These termite control methods have the major drawback that the chemicals are generally of a composition which is considered to be very dangerous for humans and that they therefore constitute a risk for the people who apply the chemicals and for the other neighbors. Under certain atmospheric conditions, chemicals can be transported at considerable distances from the area where they are applied. Thus, people who ignore the presence of chemicals, and are therefore not alerted to take protective action, may also be exposed to the potential risk of chemicals used for the fight against termites. The danger continues to exist after initial application of chemicals as long as the chemicals remain effective against termites.

 In addition, as it is necessary to establish in the ground, below the site where the forage is to be built, a high concentration of chinese products to reach a required period of protection against the entry of termites into the soil, leaching of the chemical takes place over time. This leaching naturally reduces the effectiveness of the chemical as a barrier to termites. Since chemicals in many cases are originally placed below a concrete slab on which baptize it is then erected, it is very difficult to apply other chemicals to replace those that have been removed by leaching and thereby maintain an effective barrier.

 Most importantly, chemicals leached from the ground below the building are carried by leaching water to other areas where they can be harmful to humans, animals or crops. In addition, the leached chemicals can enter rivers, streams or lakes, or underground water catchments, which can potentially distribute the chemicals over a very large area, increasing possible exposure to chemical products. It will also be appreciated that chemicals leached from construction sites over a relatively large area can collect in a single river, stream or other catchment which results in an accumulation of chemicals which degrade only very slowly.

 Many buildings, particularly houses, are constructed on a concrete slab and, although termites cannot normally penetrate concrete, cracks in the concrete frequently occur which allow termites to pass through them. this towards the building. When the cracks are of a fine nature, they provide termites with the ability to dig a path through the concrete by secreting materials which break the concrete along the fine cracks and thus allow the termites to dig through the concrete.

 In addition, in buildings constructed on a concrete slab, it is a usual practice to produce pipes or conduits which pass through the concrete slab, such as water conduits and sewer conduits. As concrete is poured in situ around these pipes or conduits, a small hole often develops around the pipe or conduit due to the shrinkage of the concrete during setting. The openings also provide access for termites through the concrete in the building structure. Thus, even when a building is erected on a concrete slab, the soil below the slab must be treated with sensitive amounts of chemicals to prevent termites from accessing these orifices.

 We also know the use of metal sheets as barriers against termites, for example galvanized steel plates on the top of posts that support a building. While this can be efficient and commercially viable with regard to building supported on poles, this is expensive and poses installation problems when considering for a building constructed on a concrete slab. Metal sheets are difficult å to assemble in situ in a way to prevent the passage of termites through the assembly In addition, if the metal sheet is thick enough to prevent an accidental hole by personnel traffic on site, it is then difficult to bend and to form according to the contours necessary to adapt to the building structure so as to create an effective barrier against termites. It would also be difficult to make a tight seal around the pipe or conduits which must pass through the sheet.

 Metal sheet including stainless steel sheet, as proposed in French patent application No. 79 04240 published as FR-A-2 453 952) is used to constitute a barrier to termites moving on a wall to enter a building in a similar way & a metal plate around a building. However, this sheet is preformed for a specific installation and it is not suitable for fabrication on site, to adapt to a range of shapes, and to a configuration allowing the integrity of a barrier against passage to be maintained. termites.

 In addition to buildings, termites attack a wide range of structures and equipment, including wooden poles and other wooden structures, underground cables, and products made from a range of materials that are attractive to termites. The only effective protection for these structures is chemical treatment or solid metal barriers that resist attack by termites.

 C1 is therefore the aim of the present invention to produce a barrier which will prevent the passage of termites in such a building or such a structure, the barrier being effective on the one hand and avoiding on the other hand the use of chemicals which are harmful to humans and / or the environment.

In order to achieve this object, the present invention provides a termite barrier material comprising a grid sheet of a material resistant to breakage in the environment of use and which is sensitive to resistance to
termite secretions and has a hardness not less than about Shore D70, the pores of the grid having a linear dimension in any direction which is not less than the maximum linear dimension of the cross section of the head the kind of controller termites
Suitably, the pores of the grid have a linear dimension in at least one direction, less than the minimum linear dimension of the cross section of the head of the termite species to be controlled. Preferably, the pores of the grid are polygonal, the maximum diagonal dimension being less than the maximum linear dimension of the cross section of the head of the species of termites to be checked.

 The termites of the species which attack wood, lumber or similar, are characterized in that they have a stubborn formed of a hard structure, appreciably undeformable. The body of these termites is a relatively soft and flexible material.

In addition, these termites have a head whose dimensions in cross section are substantially greater than those of any part of the termite body. Therefore, the cross-sectional dimension of the head determines the ability of the termite to pass through an orifice or passage as that which may exist in any form of termite barrier.

 It is also known that termites secrete a liquid saliva or material which is capable of breaking the physical structure of a large number of materials at least in particles of a dimension which can be transported by termites so as to facilitate the formation of a passage for termites. The secreted material includes, among other components, acids against fornic acid.

 The grid sheet can be laminated with a flexible plastic sheet or sandwiched between two separate sheets. Alternatively, the grid can be embedded in a plastic sheet, the two sides of the grid sheet being preferably covered with plastic. The combination of the grid sheet and the plastic constitutes a protection of the grid sheet against damage which could cause a displacement of the strands forming the grid, which would cause a widening of the openings or pores of the mesh grid, in a specific area. of it, to a dimension that would allow the passage of termites.

It should also be considered that it is a very normal practice to have a plastic sheet below the concrete slab on which a building must be built to constitute a barrier against the entry of moisture into the concrete of the building. . Therefore, by incorporating the grid sheet with or in the plastic sheet, the resulting assembly can fulfill both functions. It constitutes a barrier against humidity and against termites.
Preferably, the grid is woven from fine stainless steel wire or filaments of suitable material such as stainless steel, which is resistant to corrosion against most of the materials with which the grid will be in contact or associated during its use in the termite barrier. In particular, stainless steel resists rust when in contact with moisture, and resists attack by most acidic materials, including formic acid and by other constituents of the secretion produced by termites. .However, it should be understood that threads, strands or filaments of other materials can be used to make the grid sheet provided that the material has the necessary breaking strength when exposed to the environment, materials present in the soil and in termite attack, and which is hard enough that the particular species of termites cannot pass through the grid chewing the fibers or filaments.

Other materials can be ceramic fibers, glass fibers or hard plastics.

 It is known that the physical dimensions of termites vary from one species to another and that, in different areas of the dovetail, different species of termites are predominant. Therefore, the actual size of the grid pores will be determined by the particular species or series of termite species that must be controlled in the particular area where the grid is to be used.

 In the area surrounding Perth, in Western Australia, the most common and dangerous termites are from the Coptoterne family which have a generally flattened, generally circular cross-sectional head, shown in the shape of Figure 2B, with a linear dimension maximum between 1 and 1.5 r = L It is therefore appropriate to use in this zone a grid having pores or orifices of a maximum dimension in any direction not exceeding 0.85 mm, and preferably not exceeding not 0.6 n. To facilitate manufacture, the pores are normally of generally rectangular shape, the length of the sides being respectively 0.4 and 0.7 nm.

 The wire or filament can be of any commercial size and typically can be in the range of 0.1 to 0.2 mm in diameter. The wire or filament may have a cross section other than circular, although a circular cross section is preferred and is more readily available cossercialesent for the manufacture of grid. The grid can also be produced by stamping or drilling holes of the necessary shape in the metal sheet or film or in another suitable material of suitable thickness.

 In most species of termites, there are worker termites and soldier termites, the latter having larger heads than those of worker termites in some species, but not in all. It is believed that it is normal for soldier termites to guide workers or at least move with them. It is therefore believed that, if the grid has pores of a size capable of preventing the passage of soldier termites, this would be effective in preventing worker termites from passing alone through the grid. The workers are the ones who cause the damage and must be stopped by the gate.

 The plastic material constituting the sheet with which the grid sheet can be laminated or in which it can be embedded is suitably polyvinyl chloride or PVC, and can be any other suitable plastic which constitutes a barrier against humidity and which does not deteriorate and does not break when it is buried in the ground during the lifetime envisaged for termite barriers which can be of the order of 15 to 30 years.

 Suitably, the termite barrier is produced in sheets of any suitable size and can be produced in the form of a roll with a width on the order of 5 to 10 bolsters.

 The advantages of the termite barrier as proposed above lie mainly in the fact that there are no harmful chemicals used in the creation of the barrier, that the barrier has an effective life which corresponds to the duration life of the building. In addition, the barrier is easy to transport and apply without requiring the necessary level of precautions when handling pesticides or other chemicals and with a minimum of skill. In addition, since the barrier is in the form of a grid, it is appreciably more flexible and more easily worked, for example to cut it, make it follow the contours and form it, in particular by comparison with a sheet of solid metal.

 The invention will be understood more completely from the following description of the termite barrier applied to buildings and other uses and shown in the accompanying drawings.

In the drawings:
Figure 1 is a perspective view of a cross section of a grid as proposed for use as a termite barrier;
Figure 2a is an enlarged view of part of the grid shown in Figure 1;
Figure 2b is an enlarged top view of a typical termite, and a cross-sectional diagram of the head of this termite;
Figure 3 is a schematic sectional view of a portion of a building showing the application of the termite barrier thereto;
Figure 4 is an enlarged view of part A shown in Figure 3 where a conduit crosses the termite barrier;
Figure 5 is a cross section of part of a building to which the termite barrier has been applied in a form which is a variant of that shown in Figure 3;
Figure 6 is a perspective view of a cable in which the termite barrier has been incorporated; and
Figure 7 is a sectional view through a vertical post, the termite barrier being applied at its lower end.

 Referring now to Figures 1 and 2 of the drawings, the termite barrier takes the form of a woven grid 10 made of wires or filaments of corrosion-resistant stainless steel, such as 304 grade stainless steel. woven fabrics form a series of pores or orifices 15 in the grid which are generally rectangular in shape, the distance between the two sides 16 of the rectangle closest to each other and the diagonal thereof being less than the maximum dinensions in section transverse of the head of the termite species for which the grid must constitute a barrier (Figure 2b).

 Referring now to FIG. 3, which represents a cross section of a part of a building comprising a double exterior brick wall 20 and a single interior brick wall 21 in association with a base of poured concrete slab 23. As is conventional in this form of construction, a continuous concrete base 25 is forged to support the external double brick wall. The perimeter of the concrete slab 23 has a perimeter part 26 of increased depth also supported on the base 25, and additional zones of increased depth are also arranged below the internal walls 21 as indicated in 28 of FIG. 3.

 When the bases 25 have been poured and hardened, a sheet of one piece of termite barrier grid 30 is placed over the entire area where the slab 23 is to be poured and part of the grid being overhanging at beyond the base 25 as mentioned below. When the grid is laid, it is surrounded to closely follow the contour of the ground, including to follow the contour of any trench or depression in the ground, as necessary to adapt to the zones of increased thickness 26 and 28 of the slab of concrete. Because the termite barrier is in the form of a wire grid, it can easily deform to follow these contours, and can easily be folded when there is an excess of material from a variation of the surface contour above which it is applied. When a pipe or conduit, corme indicated at 31 must pass through the slab 23, an appropriately located orifice has been cut in the grid 30 and the edge of the grid is tightened around the pipe or the conduit as described more fully. detailed below.

 To facilitate handling, the grid is produced in rolls of an appropriate width, for example 5 meters, and the grid is placed in position, the edges of adjacent strips overlapping and being fixed together in a multiple ply joint of the type overlapping, in which, when each fold is made, it is hammered or rolled over its entire length to form a secure and permanent seal which is waterproof against termites.

 When the grid strips have been moved into position and effectively fixed along their overlapping edges, and the formwork of the concrete slab 23 is in position, the slab is poured in the conventional manner with a conventional reinforcement steel included and a moisture barrier sheet underneath. When the appropriate hardening time has elapsed, construction of the external and internal walls of the building can begin. With regard to the double exterior brick walls, as shown in Figure 1 at 20, the overhanging edge portion of the termite barrier grid is folded up so as to be disposed between the respective interior walls and The external wall is mounted to a care level 10 ci, suitably 20 to 30 above the corresponding ground level, then the barrier grid is bent outwards above the bricks forming the outer wall and, then, the rest of the bricks of the outer wall is mounted above this set.

 A complete barrier is thus formed in the double perimetric brick wall which is continuous with the barrier situated below the concrete slab to prevent the entry of termites inside the building.

 Alternatively, as shown in Figure 5, the termite barrier 30 projects outwardly below the two brick walls which constitute the outer brick double wall, and is then bent upward against the outer face of the perimeter wall, and, if desired, it can be folded over at the top and inserted between two layers of bricks at a level of 10 ci or more above ground level. Each of the above structural variants can be used in other forms of exterior wall structure, running an interior wall with a wooden frame frame and an exterior wall made of bricks. In addition, the structure shown in Figure 4 can be used with a single exterior wall with a wooden frame.

 When a conduit, counting the conduit 31 mentioned above, protrudes through the concrete slab, the grid forming a barrier, before the casting of the slab has an opening which is cut, of a dimension smaller in diameter than the conduit which must cross it. The grid surrounding the periphery of the hole thus formed can then be extended and formed into a flange 35 projecting upward or downward as shown in Figure 4, and a clamp 36 is placed around this flange to press it firmly in contact with the outer surface of the pipe 31. The clamp 36 may suitably take the form of a conventional stainless steel pipe clamp. Preferably, the flange 35 is formed so as to protrude upward from the level normal of the barrier grid, as shown in Figure 4, so that, when the slab is poured, the flange and the clamp of the firm grid around the duct are embedded in the concrete that constitutes the slab. It is understood that a woven grid can be stretched without enlarging the holes or pores to a dimension that would allow the passage of termites. The extension is obtained by twisting rectangular edges in the form of a parallelograse, which reduces the dimensions of the pores in one direction while they are increased in the other direction. The reduction in one direction is sufficient to prevent the passage of termites.

 The grid described above with reference to Figure 1 and as used in installations as described in Figures 3 and 5, can also be used as a termite barrier for a large number of structures incorporating material which can be attacked by termites. One such additional application concerns the surround of a post or the like, the lower part of which is buried in the ground. It is conventional to treat the bottom of such poles with appropriate chemicals to prevent attack by termites, but these chemicals have a limited lifespan and environmental disadvantages. of the present invention can be formed into a sleeve or pocket 38, closed at one end 39, and applied to the part of the post to be buried in the ground, the lower end being closed as shown in Figure 7. The sleeve is '' a sufficient length to project at least 10 to 20 cn above the ground level when the post is mounted.

 When the barrier grid is to be used for this purpose, it can be originally woven into a rectangular shape and then cut to the length necessary for each particular application. Individual lengths of the tubular sheet are then folded over at the bottom end to provide an effective closure. This closure can be formed by flattening a part of the end of the tube and then forming multiple folds therein, the folded part being subsequently compressed or hammered flat to form a multiple layer overlapping joint in which cannot penetrate termites.

 When the grid is not produced in tubular form, a flat piece of grid can be rolled to form a tube, the respective edges of the strip being folded into a multi-ply joint which is itself laminated or hammered flat.

 In the above description of the application of termite barrier material to the lower end of a post, it should be understood that the same barrier construction can be used on any organ and must be buried in the ground, which 'It is of the nature of a pole or that it fulfills the function of a pole or for any other purpose.

 Another use of the termite barrier material relates to the protection of cables, and in particular of underground cables which incorporate a material which is susceptible to attack by termites. Such cables are normally of a construction similar to that shown in Figure 6 and have an outer protective covering 40 of suitable material in addition to the wires or other elements 41 of the cable, such as an electrical or optical cable, and normal insulation or other coverings or packaging 42 in which they are located.

It is known to weave in situ, around the core of such cables, woven or wire reinforcement materials, and it is proposed in the present invention to also weave around such a cable cores of a sheath of wires or 43 stainless steel filaments of appropriate size to constitute a barrier against the passage of termites in the cable. If the termite barrier is not woven in situ, around the core of the cable, a packaging made of barrier material of the structure requested can be applied around the cable, a continuous seam being formed by a lap joint as described above. As an alternative to the location surrounding the outer cable, as shown in the drawing, the termite barrier can be located in the hard outer coating made on such cables or below it.
The termite barrier, as described above, can, without departing from the present invention, be used in many other applications, in addition to those described with reference to the accompanying drawings.

Claims (11)

 1. Termite barrier material comprising a grid sheet <10) of a material resistant to breakage in the environment of use and substantially resistant to termite secretions and having a hardness of not less than about Shore D70, the pores (15) of the grid <10) having a linear dimension in any direction which is not less than the maximum linear dimension of the cross section of the head of the species of termites to be checked.  2. Material according to claim 1 wherein the pores (15) of the grid (10) have a linear dimension in at least one direct ion which is less than the minimum linear dimension of the cross section of the head of the species of termites to control.  3. Material according to claim 1 wherein the pores (15) of the grid (10) are polygonal, the maximum diagonal dimension being less than the maximum linear dimension of the cross section of the head of the species of termite 9 to control.  (. Material according to claim 1, 2 or 3, wherein the pores (15) of the grid (10) are rectangular.  5. Material according to claim 4 wherein said rectangular pores <15) have a diagonal dimension of less than 0.85 n  6. Material according to claim 4, in which the rectangular pores <15) are of dimension O, 40 fl by 0.70 ma  7. Material according to any one of claims 1 to 6, in which the grid 10 is made of corrosion-resistant quality stainless steel.  8. Material according to any one of claims 1 to 7, wherein the grid (10) is assembled on a sheet (30) impermeable to moisture or is embedded therein.  9. Continuous layer <30) of termite barrier material according to any one of claims 1 to 8, produced in combination with a building structure erected on a concrete floor slab (23), below the lower side of the slab, said layer of termite barrier material extending towards the perimeter of the slab (23) in all directions and upward around the complete perimeter of the slab <23> 8 a certain distance around the slab and the level of the ground which surrounds it.  10. member 131) projecting through the layer <30) of termite barrier material and through the slab <23) in the combination according to claim 9, and ronchon (35) of termite barrier material, in one piece with the layer of termite barrier material located around the periphery of the organ <31), and tight <36) in pressure contact with the latter around the complete perimeter of the organ (31 ).  11. A hole surrounding the sleeve (35) in the combination of claim 10, wherein the sleeve (35) is formed by cutting said hole in the layer (30) of termite barrier material, said hole having a lower perimeter at the perimeter of the member (31), and extending and flexing the edge area of termite barrier material around the opening to form the sleeve (35).  12. Cable having a core comprising a conductive member or members and a protective coating <38) surrounding the core, said coating comprising a continuous tube of termite barrier material, according to any one of claims 18 8, surrounding said core  13. Barrier against termites consisting of the material and / or members mounted thereon according to any one of the preceding claims.