AU698397B2 - Termite barrier for building slab penetrations - Google Patents

Description

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iT -rl-~ P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 *4e* 4 4.

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4* 4 4S COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor(s): Address for Service: GRANITGARD PTY LTD Francis John STEWART

OBERINS

Patent and Trade Mark Attorneys 530 Collins Street Melbourne, Victoria, 3000, Australia Invention Title: TERMITE BARRIER FOR BUILDING SLAB

PENETRATIONS

The following statement is a full description of this invention, including the best method of performing it known to me: -1j i i

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The present invention relates to a termite barrier for building slabs and building slab penetrations. More particularly the invention relates to the protection of buildings against subterranean termite attack.

The need for the protection of houses and other buildings against subterranean termite attack is well known. Perhaps the most common method of protection has been to spray DDT or other insecticides on the ground immediately beneath and surrounding the building requiring protection.

However spraying the ground with insecticides having long-lasting potency can have adverse consequences particularly about dwellings as severe allergy and other adverse reactions may result. Accordingly it is most preferable to avoid such spraying wherever possible.

It has long been known to form a concrete slab as a footing upon which a building is erected. The technique typically involves levelling the site, and digging one or more trenches which, when filled with concrete, form beams to strengthen the slab and to distribute the weight of the structure erected thereon across the substratum. Such beams typically extend around the perimeter of the slab and there may be one or more transverse and/or longitudinal beams depending upon the design of the desired slab and building. Typically such strengthening beams are required below any load-bearing wall. The desired building can be erected on the upper surface of the slab after the concrete in the slab has cured to a sufficient strength.

In earlier Australian Patent Application No. 15980/92 there was disclosed a sacrificial formwork for concrete comprising a plurality of panels adapted for "lining the walls and optionally the base of a trench for forming a beam beneath a concrete slab. The prior application also disclosed a method for forming a concrete i building slab utilising sacrificial formwork in which the walls and floor of each trench and the site below the slab are covered with a physical termite barrier.

In our co-pending Australian Patent Application No. 59166/94 we disclose forming a physical termite barrier beneath a building slab by providing a substantially horizontal layer of graded aggregate between any substantially horizontal surfaces on the substratum and the underside of the slab. That application also describes the provision of a physical termite barrier between the building slab and any building slab penetrations, such as pipework or service connections.

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However, it has been found that over time the substrate upon which a slab is poured can subside leaving a gap between the graded aggregate and the underside of the slab. This subsidence may be particularly pronounced in the region of a slab penetration. This is because a trench dug to receive a pipe or other service conduit which penetrates the slab is likely to be backfilled in a manner particularly prone to subsidence.

Where subsidence generates a gap between the graded aggregate and the underside of the slab, any aggregate placed in the gap between the aperture in the slab and the pipe or other conduit penetrating through the slab is liable to flow downwardly. Thus the gap may become devoid of aggregate and hence become a prime site for termite access to the building.

Accordingly the present invention provides in one embodiment a method for forming a physical termite barrier in a building aperture, said method including the steps of securing a holder for a physical termite barrier across a building aperture, wherein the holder is positioned in or adjacent a proposed site for the building aperture prior to the formatin of the aperture, and placing a layer of graded aggregate or other suitable stone type in said aperture whereby said aggregate is retained by said holder in said aperture whereby to form a physical termite barrier.

The present invention provides in another embodiment a holder capable of use in the method of the invention, said holder including a support for retaining a physical termite barrier, and an anchoring arrangement capable of bonding to a building slab to be laid about the building aperture whereby to assist securing of the position of the holder relative to the building aperture, said anchoring arrangement comprising one or more ridges, wings or lugs upturned or extending outwardly from the support.

The present invention also provides in other embodiments a novel method for forming a building slab, and a building slab having a physical termite barrier.

The term slab penetration is used in relation to the present invention to include any pipework, conduit or service connection provided for a building and extending through the building slab, such as plumbing, gas and electricity connections.

The term building aperture is used in relation to the present invention to include any opening extending through a slab or wall of a building. The term building aperture as used herein therefore includes any gap or void between a slab and a slab penetration, any gap or void between two slabs, such as in the case of construction joints, and any weep hole or ventilation slit extending through a wall or flooryof a building.

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A holder according to the present invention may be of any type which is capable of retaining a physical termite barrier material within a building aperture.

Preferably the holder is capable of being positioned in or about a building aperture formed adjacent a slab penetration. The holder preferably fully surrounds the perimeter of the slab penetration, whereby the holder is capable of retaining the physical termite barrier material in proximity to the perimeter surface of the adjoining slab or slab penetration. This construction may be adapted to maintain contact between the physical termite barrier material and the perimeter surface of the slab penetration or an adjoining slab, preventing possible pathways for termites from forming in the building aperture between the slab and the slab penetration.

The holder may be suitably positioned across, in or adjacent the proposed building aperture prior to laying the building slab.

The holder is preferably positioned between the substratum and the slab prior to laying the slab whereby the holder becomes embedded in the slab to some degree when the slab is laid and thereby positioned to support a physical termite barrier material placed thereon and thereby retain the barrier material within the building aperture. Preferably the holder becomes at least partially embedded in the laid slab.

The holder may be apertured to facilitate positioning of the holder adjacent 20 -and preferably substantially surrounding a slab penetration. The internal diameter or width of the holder aperture is preferably slightly larger than the perimeter dimension of the slab penetration whereby to enable the holder to be positioned around the perimeter of the slab penetration. The shape of the holder is suitably adapted to conform with the cross-sectional shape of the building aperture or slab penetration.

The construction and arrangement is preferably such that there is minimal clearance between the holder aperture and the slab penetration, whereby the clearance between a physical termite barrier material retained by the holder and the slab penetration does not allow for the escape of the physical termite barrier material. In one preferred arrangement the holder is capable of engaging with the slab penetration. Accordingly the holder may include an engaging arrangement.

The engaging arrangement may be formed about an aperture in the holder. The engaging arrangement is preferably such that sealing engagement with a perimeter surface of the slab penetration results. The area of engagement is preferably u~1. i IT r r ji 1 T .fq 1~~i I -I h 1, o J, "I C nrl I _1 ei i ~r9 m- *4*f S S 5* 4 4* S 4 4-

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4ie sufficiently flexible to permit a degree of relative movement between the holder and the slab penetration. The arrangement is preferably also such that abrading of the slab penetration does not occur to any appreciable extent as a result of any relative movement between the holder and the slab penetration.

The holder may engage the slab penetration in one or more of a number of ways. The holder aperture may include one or more fingers to engage the surface of the slab penetration. The aperture may include a web. The aperture may be flanged. The holder may in one embodiment be adhered to the slab penetration at any point of contact with the slab penetration. The flanged aperture may be clamped, sealed or otherwise secured to the slab penetration to prevent the passage of termites between the holder and the slab penetration.

In one preferred embodiment, the holder comprises a grate. The grate may be of a substantially planar construction. For example, the holder may comprise a substantially planar sheet of a mesh material. The pore dimension of the 15 interstices of the mesh sheet may be selected so as to be less than the average minimum dimension of the particles of the physical termite barrier material to be retained by the holder. The pore dimension may in one preferred embodiment be at least 0.5mm, and more preferably in the range of from 1.5 to 2mm.

In an alternative arrangement in accordance with the present invention the 20 holder comprises a substantially planar sheet of material impervious or substantially impervious to the physical termite barrier material and/or termites. One such material may include unplasticised PVC.

In another embodiment, a holder according to the present invention comprises a collar. The collar may be capable of being positioned adjacent the 25 perimeter surface of the slab penetration.

In another embodiment, a holder according to the present invention comprises an apertured cup.

In another embodiment, a holder according to the present invention comprises a container. The container may be in the form of a trough. The trough may be substantially U-shaped. The trough may run across, parallel to, beneath or alongside a building aperture, such as a construction joinw. In one preferred embodiment of this arrangement, the holder comprises a substantially U-shaped trough filled with a physical termite barrier material retained by the holder beneath a construction joint. The trough may include one or more lugs capable of bonding to the slab to be laid. The arrangement may be such that at least one lug is positioned such that it will become partially embedded in one slab, whilst at least

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S.e .*r *qtt *e ta1 5r a a a *i Vt a S AL S one other lug is positioned such that it will become at least partially embedded in an adjacent slab, on casting of the slabs. A trench may be dug at the site of the proposed construction joint prior to laying abutting slabs whereby to locate the trough relative to the construction joint. The trough is then positioned in the trench and filled with a physical termite barrier material. When the abutting slabs are cast the lugs of the trough become at least partially embedded in adjacent slabs whereby to secure the holder across the building aperture between abutting slabs and thereby to form a physical termite barrier for the construction joint. The arrangement may be such that the layer of graded aggregate held by the trough extends a minimum of approximately 75mm in each direction from an edge of the slab.

A holder according to the present invention may be at least partially lined with a cushioning material. The cushioning material may comprise a felt, such as a lubricated felt.

In a further embodiment, a holder according to the present invention 15 comprises a cage. The cage may be capable of being positioned in the building aperture formed adjacent to the slab penetration. In one embodiment of this arrangement, the holder is generally in the shape of the building aperture formed adjacent the slab penetration across which the holder is to be positioned. For example, where the slab penetration is substantially circular, the gap or void formed around the slab penetration may also be substantially circular, whereby the holder may comprise a substantially cylindrical sleeve capable of being positioned in the gap or void and extending about or around at least part of the perimeter of the slab penetration.

Other holder shapes and constructions are also envisaged within the scope of the present invention. These may include, for example, a disc, or a flange. The disc or flange may be substantially circular.

A holder according to the present invention may be capable of being anchored to the building slab. Accordingly the holder may include an anchoring arrangement. The anchoring arrangement may be installed so as to form a termite resistant bond between the holder and a building slab. The anchoring arrangement may assist the holder to maintain its position relative to the building aperture, or relative to the building slab and a slab penetration. The anchoring arrangement may be constructed and arranged whereby to allow for a degree of independent movement between the slab and slab penetration or within the building aperture.

The anchoring arrangement may be capable of bonding to the slab to be laid. In one jl i-

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embodiment, the anchoring arrangement comprises one or more ridges, wings or lugs. The ridges, wings or lugs may be disposed on the holder, and/or about the periphery of the holder. The wings may be upturned or outwardly extending. This arrangement has been found to assist bonding of the holder to the slab.

In one particularly preferred arrangement according to the present invention a holder comprises a substantially planar web of mesh material with a plurality of peripheral sections upturned to form wings extending out of the plane of the web. The arrangement is preferably such that the holder may be laid on the substratum upon which a slab is to be poured such that after pouring and curing, also sometimes known as casting, the web of the holder is substantially flush with the underside of the slab and the wings are embedded in the slab.

Other anchoring arrangements are also envisaged within the scope of the present invention.

A holder according to the invention may be formed from one or more 15 components. If the holder is formed from one component, the holder is preferably apertured to a dimension larger than the width of a slab penetration. This arrangement enables the holder to be slipped over a slab penetration and positioned relative to the penetration whereby to retain the physical termite barrier material in the gap or void adjacent the penetration. The holder aperture is preferably located 20 on a central axis of the holder.

A holder comprising two or more components can be used to retain the physical termite barrier material in the building aperture whilst providing for a degree of independent movement of the components of the holder.

If the holder is formed from a number of components, the components of the holder are preferably constructed and arranged such that when assembled an aperture in the holder is defined which is larger than the perimeter dimension of the slab penetration. This arrangement enables the holder to be positioned in the gap or void adjacent the slab penetration.

A holder according to the invention may be fabricated from any suitable material. Examples of suitable fabrication materials include sheet or mesh materials, metal, stainless steel, stainless steel mesh, plastics materials, flexible rubberised compounds, fabric materials, fibrous materials, scourer-type materials, including those formed from loose matrices of abrasive fibres coated with a plastics material, and polythene, unplasticised PVC, or neoprene. Other fabrication materials suitable for a holder according to the invention include those which retain moisture and do not allow it to seep through either from or to the substratum to any appreciable extent.

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Other materials for fabricating the holder are also envisaged within the scope of the present invention. Most preferably the holder is formed from a termite resistant material. The design of the holder may make it less susceptible to termite attack, for example by utilising smooth surfaces, or rounded angles or joints.

A holder according to the invention does not necessarily function as a physical termite barrier. If for example the holder comprises a mesh sheet, the interstices of the sheet may be selected so as to act as a barrier to impede the progress of termites. The material selected may be such that it is capable of preventing termites chewing through the material. One such suitable material comprises a stainless steel mesh, marketed under the trade mark TERMI-MESH. It is also envisaged within the scope of the present invention that the interstices of the mesh are larger than the size required to act as a physical termite barrier. The interstices of the mesh should however be of a dimension suitable for retaining a graded stone aggregate within the building aperture to act as a physical termite barrier.

A. building aperture according to the present invention is preferably formed around at least part of the perimeter of the slab penetration. The building aperture preferably forms an annulus around the slab penetration whereby the building aperture extends fully around the perimeter of the slab penetration. The building 20 aperture may be of a cross-sectional shape which substantially conforms to the cross-sectional shape of the slab penetration, but of larger width or diameter than that of the width or diameter of the slab penetration.

In another arrangement according to the present invention, a building aperture in the form of a cavity may be formed between inner and outer walls of the building. A holder according to the invention may be positioned adjacent to or within any weep hole in the wall of the building so as to retain a physical termite barrier material placed in the cavity defined between the inner and outer walls. A weep hole opening is preferably covered by a durable material. The durable cover may be secured within the weep hole. The material selected may also be capable of resisting corrosion, termite attack or damage by rodents, and allowing the free passage of air and water.

Formwork in the form of a collar may be placed around the slab penetration prior to the slab being laid whereby to assist in forming a building aperture in the form of a gap or void around the penetration after the slab has been laid. When the slab has set for a time which is sufficient such that any substantial movement of the slab is unlikely to ,occur, the formwork may,. be removed from 'C ~r t.

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around the penetration. If not embedded in the slab or otherwise positioned the holder may be positioned to retain the physical termite barrier material, such as a graded stone aggregate. The graded stone aggregate may be installed in the building aperture whereby to form a physical termite barrier.

In one particularly preferred arrangement according to the present invention a building aperture in the form of a gap or void is formed in a building slab by preparing a substratum on which the slab is to be laid, excavating for a building slab penetration, fixing the desired position of the slab penetration with respect to the slab to be laid, positioning a holder according to the present invention to be formed around at least part of the perimeter of the slab penetration, providing a formwork about the slab penetration, removing the formwork after the slab has been laid and cured for a sufficient time whereby to form a building aperture, and retaining a physical termite barrier material in said aperture by said holder, whereby to form a physical termite barrier.

A physical termite barrier according to the present invention may be any physical barrier which is impervious or substantially impervious to termites. In one embodiment, the physical termite barrier may comprise a suitable stone type. In one preferred embodiment, the physical termite barrier may include a layer of graded aggregate. The graded aggregate used in accordance with the present invention is preferably a graded granite aggregate and most preferably a graded granite aggregate which has received National Accreditation from the Australian Uniform Building Regulations Coordinating Council (or equivalent).

One product suitable for use as a graded stone aggregate in accordance with the present invention is marketed under the trade mark GRANITGARD.

Most preferably the graded aggregate used in accordance with the present invention comprises graded stone screenings having a dimension generally in the range of 1.13 to 5mm, and more preferably in the range of from 1.18 to 3.15mm.

The aggregate is preferably graded to facilitate packing or fitting and to minimise interstices. Most preferably the aggregate is graded for size, shape and composition.

A physical termite barrier according to the present invention may be retained by the holder in a number of ways. In one embodiment, the physical termite barrier may be retained by placing the physical termite barrier oil the holder whereby the physical termite barrier material is retained from beneath by the holder. Other retaining arrangements and holder orientations are envisaged within the scope of the present invention.

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i\ $:i b I i x /A -1 I* Y IP ~-IU A physical termite barrier material according to the present invention may be laid di ,nly into a building aperture formed with the holder in place to retain thei physical termite barrier material. A physical termite barrier material in the form of an aggregate layer may be lightly compacted in the aperture. In one preferred embodiment, a graded aggregate layer in accordance with the invention may substantially fill the building aperture and be compacted to ensure complete contact with the adjoining slab penetration or building aperture surrounding the slab penetration. In an alternative embodiment, a graded aggregate layer in accordance with the present invention may be installed in the building aperture to a minimum depth of about In one embodiment of the invention, a formwork such as a foam collar is placed around the slab penetration, and after the slab has been laid and set to a sufficient extent that substantial movement will generally not result, the formvwork ,t is removed and the gap or void filled with graded aggregate. The formwork may comprise sacrificial formwork which may be dissolved or otherwise sacrificed to form the aperture.

"In another preferred arrangement according to the present invention a physical termite barrier for a building is provided by ensuring that any building apertures are provided with a holder according to the present invention, the holder r e 20 retaining a physical termite barrier material within the building aperture.

E ~To further assist in the understanding of the present invention, particularly t t preferred embodiments of the invention will now be described in relation to the accompanying drawings. In the drawings: riu Figure 1 is a cross-sectional view of a typical building construction 25 arrangement according to one embodiment of the present invention, Figure 2 is a plan view of a typical holder according to one embodiment of the present invention, Figure 3 is a section through the line A-A of Figure 2, Figure 4 is a perspective view of the holder of Figure 2, and Figure 5 is a cross-sectional view of a typical building construction joint according to one embodiment of the present invention.

Figure 1 shows a building slab 1 of conventional form including a capping layer 2 and an edge beam 3. Slab 1 includes an upper surface 4 which generally forms the floor of a building erected on slab 1. Edge beam 3 of slab 1 includes a step or rebate 5 of conventional form adapted for receiving an outer brick wall 6.

Inner lining wall 7 is erected on upper surface 4 of slab 1. The slab 1 is laid directly over the prepared substratum 9 such that the lower surface 8 of slab 1 abuts 11.

the upper surface of the substratum 9. A vapour membrane (not shown) may be interposed between the prepared substratum 9 and the slab 1 prior to laying of the slab 1.

Slab penetrations 10 and 11 are provided through slab 1 via building apertures in the form of gaps or voids 16 and 17 respectively. The slab penetrations may be plumbing or other service connections, and may be suitably lagged as shown at 22. Prior to laying of the slab 1, the site of the slab penetration is determined, and formwork (not shown) as described herein positioned to define a building aperture adjacent the slab penetration.

A typical holder 14 according to the invention is shown in the embodiment of figure 2. Holder 14 is capable of retaining a physical termite barrier material placed thereon, and in the embodiment shown comprises a grate in the form of a square and substantially planar mesh sheet 23. The apertures of the mesh are suitably of a dimension in the range of from 1.5 to 2mm.

d15 Holder 14 also includes a central aperture 26 of a dimension slightly larger att to, T than the perimeter dimension of the slab penetration in the form of pipe 10. Holder 14 in the embodiment shown fully surrounds pipe 10. The holder 14 is suitably t V, engaged with the surface of the pipe 10 in the region of aperture 26, such as by adhesion, a flange arrangement and so on.

Holder 14 includes upturned corners or wings 24 at the perimeter of the holder 14. Wings 24 are capable of bonding to and/or being embedded in slab 1 and retaining the position and orientation of holder 14 with respect to the slab penetration 10, on laying of the slab 1.

,,Formwork in the form of a removable collar 25 fabricated from 25 polystyrene or other suitable material such as metal or foam. is positioned around the slab penetration 10 generally in the longitudinal direction of the penetration Formwork 25 is removed after concrete slab 1 is cured.

H,.olders 14 and 15 are shown in figure 1 in position adjacent the slab penetrations 10 and 11 respectively. In the embodiment shown in figure 1, holder 14 is interposed between substratum 9 and slab 1 with wings 24 being embedded in slab 1. The apertured holder 14 is preferably positioned in the vicinity of the intended building aperture 16 prior to laying of the slab 1 by slipping the holder over the slab penetration to the upper surface of substratum 19.

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p1 A slab penetration in the form of an electrical conduit 20 includes a layer of GRANITGARD graded granite aggregate placed in the cavity between inner wall 7 and outer brick wall 6. In the embodiment shown, conduit 20 does not include a holder, however it will be appreciated that a suitable holder 14 can be positioned if necessary around the juncture of the conduit 20 with edge beam 3.

A physical termite barrier material in the form of a layer of GRANITGARD graded granite aggregate 18 is placed on holders 14 and 15 in building apertures 16 and 17 to provide a physical termite barrier. The provision of a holder as described for the physical termite barrier prevents to any appreciable extent the displacement of physical termite barrier material from a region in close proximity to the pipe 10 as a result of relative movement of the slab or substratum with respect to the pipe Figure 5 shows an arrangement for forming a physical termite barrier for a building aperture 44 defined between abutting slabs 31 and 32, sometimes known as a construction joint. In this embodiment, the holder comprises a substantially Ushaped trough 35. Trough 35 includes a pair of lugs 36 and 37 extending upwardly from the arms of the U. Lugs 36 and 37 are capable of bonding to the slabs 31 and 32 to be laid. In the embodiment shown, lug 36 is arranged so that it will become at least partially embedded in slab 31 on laying of the slab, whilst lug 37 is arranged 20 so that it will become at least partially embedded in adjacent slab 32 on laying of that slab. Lugs 36 and 37 extend approximately 25mm into the slabs on laying of the slabs to assist in securing the trough 35 relative to construction joint 44.

In the embodiment shown, trough 35 includes a pair of supports 38 and 39 extending outwardly from respective arms of the U of the trough 35. Supports 38 and 39 are arranged so as to lie beneath the underside of slabs 31 and 32 respectively between the substratum 33 on which the slabs are laid and the underside of the slabs. A vapour barrier or membrane 45 may be interposed between the substratum 33 and the underside of slabs 31 and 32.

In the embodiment shown, the base 41 of the trough 35 is formed from a flexible material, such as an unplasticised PVC. Base 41 comprises a pair of overlapped sections.

In the embodiment shown, a layer of cushioning material 40, such as a lubricated felt is provided between the base 41 of the trough 35 and the graded aggregate 42.

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Trough 35 is arranged so as to underlie construction joint 44 for the length of the construction joint 44. A trench 34 is dug in the substratum 33 at the site of the proposed construction joint 44 prior to laying slabs 31 and 32 so as to locate the trough 35 relative to the construction joint 44. Vapour barrier 45 is placed on substratum 33, and trough 35 is then positioned in the trench 34 thus formed and filled with a layer of graded stone aggregate 42 and the slabs poured. The layer of graded aggregate 42 held by trough 35 extends a minimum of approximately in each direction from an edge of slabs 31 and 32. Construction joint 44 may be at least partially filled with a suitable joint sealant material 43, and/or at least partially filled with graded aggregate.

In use, with reference to figure 1 substratum 9 is prepared on which a concrete slab 1 is to be laid, including excavation for one or more slab penetrations.

A holder according to the invention is laid on the substratum 9 around the perimeter of the slab penetration, and either adhered to or engaged with the slab penetration as S 15 desired. Formwork in the form of collar 25 is placed over the slab penetration such as pipework to define a building aperture around the penetration, whereupon the final position of the slab penetration is fixed. The slab 1 is laid and cured, and the formwork is removed, such as by dissolving with an organic solvent. A layer of physical termite barrier material, such as for example a graded stone aggregate is placed in the building aperture formed around the slab penetration to a minimum S o depth of approximately 75mm. The physical termite barrier material may then be ***compacted.

The holder provided by the present invention is capable of being readily installed to prevent termite access and maintain the integrity of the physical termite 25 barrier material with respect to a building aperture.

A building may thus be protected from termite attack by the provision in any building aperture of a physical termite barrier material retained by a holder according to the present invention.

While it has been convenient to describe the invention herein in relation to particularly preferred embodiments, it is to be appreciated that other constructions and arrangements are also considered as falling within the scope of the invention.

Various modifications, alterations, variations and/or additions to the constructions and arrangements described herein are also considered as falling within the ambit and scope of the present invention.

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Claims (28)

1. A method for forming a physical termite barrier in a building aperture, said method including the steps of securing a holder for a physical termite barrier across a building aperture, wherein said holder is positioned in or adjacent a proposed site for the building aperture prior to the formation of the aperture, and placing a layer of graded aggregate or other suitable stone type in said aperture whereby said aggregate is retained by said holder in said aperture whereby to form a physical termite barrier.

2. A method according to claim 1, wherein said building aperture is formed by laying a building slab about the proposed site for the building aperture, whereby on laying the slab said holder becomes at least partially embedded in the slab and thereby secured across the building aperture thus formed.

3. A method according to claim 1 or 2, wherein said holder includes an anchoring arrangement whereby to assist the holder to secure its position relative to the building aperture.

4. A method according to claim 3, wherein said anchoring arrangement comprises one or more ridges, wings or lugs extending from the holder.

5. A method according to claim 4, wherein said ridges, wings or lugs are upturned or outwardly extending whereby to assist bonding of the holder to the building slab.

6. A method according to any one of the preceding claims, wherein said layer of graded aggregate substantially fills said aperture.

7. A method according to any one of the preceding claims, wherein said building aperture is formed adjacent a building slab penetration.

8. A method according to claim 7, wherein the holder at least partly surrounds the perimeter of the slab penetration, whereby to retain the physical termite barrier material in proximity to the perimeter surface of the slab penetration.

9. A method according to claim 7 or 8, wherein said holder is apertured whereby to position the holder at least partly around the slab penetration.

10. A method according to any one of claims 7 to 9, wherein said holder includes an engaging arrangement whereby to engage part of the holder with a perimeter surface of the slab penetration.

11. A method according to claim 10, wherein said engaging arrangement is formed about an aperture in said holder. tT'~ I\ '1 agb/stds4OA0l63995 4 f t r C' C C C, C C C C C 'V C I C tC C Cc PC C C C C t CC CCCI C C~ C CC CC CCC C C C C Ci. CC a C C C

12. A method according to claim 10 or 11, wherein the engaging arrangement comprises one or more fingers arranged about an aperture in said holder to engage a perimeter surface of the slab penetration.

13. A method according to any one of claims 7 to 12, wherein the holder aperture includes a web or flange to engage a perimeter surface of the slab penetration.

14. A method according to any one of claims 7 to 13, wherein said holder comprises a collar capable of being positioned adjacent the perimeter surface of the slab penetration.

A method according to any one of claims 7 to 13, wherein said holder comprises an apertured cup.

16. A method according to any one of claims 7 to 13, wherein said holder comprises a cage capable of being positioned in the building aperture formed adjacent the slab penetration.

17. A method according to claim 16 wherein said cage comprises a sleeve capable of being positioned in the building aperture and extending about at least p~art of the perimeter of the slab penetration.

18. A method according to any one of the preceding claims, wherein said physical termite barrier comprises a graded granite aggregate.

19. A method according to any one of the preceding claims, wherein said physical termite barrier is lightly compacted in the building aperture.

A method according to any one of the preceding claims, wherein said physical termite barrier is placed in the building aperture to a minimum depth of about 75 mmn.

21. A method for -forming a physical termite barrier in a building aperture, substantially as hereinbefore described and with reference to any one of the accompanying drawings.

22. A method for forming a building aperture containing a physical termite barrier including the steps of preparing a substratum on which a building slab is to be laid, excavating for a building slab penetration, fixing the desired position of the slab penetration with respect to the slab to be laid, positioning a holder around at least part of the perimeter of the slab penetration, providing a formwork about the slab penetration, removing the formwork after the slab has been laid and cured for a sufficient time whereby to form a building aperture, and retaining a physical termite barrier material in said aperture by said holder, whereby to form a physical termite barrier. H-I. 77 I H 16.

23. A method according to claim 22, wherein formwork is placed at the proposed site for the building aperture prior to the slab being laid whereby to assist in forming the building aperture on laying of the slab.

24. A method according to claim 23, wherein said formwork comprises a sacrificial collar capable of surrounding a slab penetration about which said aperture is formed.

A holder capable of use in the method of any one of the preceding claims, said holder including a support for retaining a physical termite barrier, and an anchoring arrangement capable of bonding to a building slab to be laid about the building aperture whereby to assist securing of the position of the holder relative to the building aperture, said anchoring arrangement comprising one or more ridges, wings or lugs upturned or extending outwardly from the support.

26. A holder according to claim 25, wherein said holder is apertured whereby to locate the holder at least partly around a slab penetration adjacent which said building aperture is formed. i

27. A holder according to claim 25 or 26, and further including an engaging S, arrangement whereby to engage part of the holder with a perimeter surface of a slab penetration adjacent which said building aperture is formed.

28. A holder capable of use in the method of any one of claims 1 to 24, 5 i substantially as hereinbefore described and with reference to any one of the accompanying drawings. DATED this 3rd day of September 1998 OBERINS ARTHUR ROBINSON HEDDERWICKS Patent Attorneys for GRAN1TGARD PTY LTD f ABSTRACT A method for forming a physical termite barrier in a building aperture is disclosed. The method includes the steps of securing a holder across the aperture, placing a layer of graded aggregate or other suitable stone type in the aperture whereby said aggregate is retained by the holder, whereby to form a physical termite barrier. The physical termite barrier preferably includes a graded granite aggregate. A holder capable of use in the method is also disclosed. .too *q 0 4 44 9 0 *4 0:6. IV