AU2009236007B2 - Insecticide Treated Insulation and Surrounds - Google Patents

Abstract

A method for the control of crawling insects in a building structure having at least one cavity containing a solid insulation product in contact with building components defining and/or within the cavity, the method comprising applying a surface coating of a residual insecticide such that respective contacting surfaces of the solid insulation and building component are coated with the insecticide.

Description

AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION PATENT Invention Title: "Insecticide Treated Insulation and Surrounds" The following statement is a full description of this invention, including the best method of performing it known to me/ us: 1 METHOD FOR THE CONTROL OF CRAWLING INSECTS FIELD OF THE INVENTION 5 The present invention relates to a method for the control of crawling insects in a building structure and in particular relates to the control of insects in a domestic dwelling. 10 BACKGROUND OF THE INVENTION The present will be described with particular reference to a method of controlling crawling insects in domestic buildings. However, it will be appreciated that the method of the present invention is applicable to any building structure in which the 15 control of crawling insects is desired. The presence of crawling insect pests such as cockroaches, silverfish, ants, spiders, carpet beetles and the like is clearly undesirable. These insect pests are generally brought into or enter a building in bags and boxes. Cardboard boxes in 20 particular are favoured places for cockroach eggs and many homeowners inadvertently introduce cockroaches when they move into a new home. Cockroaches in particular like warm, dark places where they hide during the day and emerge during the night. They favour cracks and crevices where they can contact the top and bottom surfaces with their body. These insect pests typically 25 breed in wall and roof voids and can rapidly breed virtually undetected. Thus, it may be appreciated that by the time a home-owner notices the presence of insect pests, the infestation may be large and established.

2 Current commercial methods of pest insect control are all directed towards controlling infestations. This is commonly done using chemical control. In order for such control to be effective, it is necessary to be able to treat their hiding places and not just those areas where insects traverse. Typical treatment areas 5 are behind loose baseboards, in cracks underneath cupboards, around the kitchen sink and the like. It is however, not possible to treat inside wall cavities without drilling into the wall space. Although there are a number of termite control methods and devices that rely upon injecting or otherwise dispersing an insecticide into a wall cavity, homeowners generally do not want holes to be drilled 10 in their walls. A single chemical treatment carried out as described above will kill those insects in the treated areas. However, it will not kill those insects that are in those places where the chemical treatment cannot reach. Consequently follow up treatments 15 are generally required as the insects continue to breed undetected. It will be appreciated that the pest control industry is a very large and important industry in countries such as Australia in which there are many experienced persons and competition is high. 20 The use of insulation in wall cavities and ceilings in Australia is well known. There is an extremely wide range of insulation types available. One of the earliest forms of insulation was cellulose in the form of newspaper. Cellulose is now used as a loose-fill insulation consisting of shredded or granulated waste paper. Cellulose 25 must be impregnated with a fire retardant and a borate salt or boric acid is commonly used. The fire retardant is typically added to a cellulose slurry so that it is evenly dispersed throughout the cellulose. Such even dispersion is important for fire retardation, 3 Boron is also toxic to crawling insects. Boron must be ingested before it can kill an insect. It does not kill by contact. It is widely believed that borate treated cellulose insulation can control insects. However, this is not necessarily the case as the requirement for fire retardancy and the control of crawling insects is quite different. 5 Fire control requires an intimate mixing of a fire retardant and cellulose. This is often done by treating a cellulose slurry with a borate. On the other hand, in order to control a crawling insect using a boron compound, a surface must be covered with a fine coating of the compound that can be collected 10 on the insects legs or body as it traverses the surface. Upon self-grooming, the insect ingests the insecticide and subsequently dies. Thus, borate treated cellulose insulation may be toxic to termites that may eat the cellulose, but it is not necessarily toxic to crawling insects such as cockroaches. 15 Wool is another material used for insulation. It is impregnated with insecticides to protect against damage from insects that feed on the wool. Such insects include carpet beetle and clothes moth. Again, control relies upon the insect eating the wool. That this method of treatment is ineffective against crawling insects is evidenced by the fact that homes having wool batt insulation are still subject to 20 cockroach and other crawling insect infestation. There are also a large number of insulation products formed from synthetic materials that are not a food source for insects. Such insulation types are referred to as "insect resistant". This does not mean that they in any way assist in the 25 control of insects, this term simply mean that the insects do cannot not use the insulation as a food source. The present invention, therefore relates to a method for the treatment and/or control of crawling insects in a building structure. 30 4 SUMMARY OF THE INVENTION According to a first broad form of the present invention, there is provided a 5 method for the control of crawling insects in a building structure having at least one cavity containing a solid insulation product in contact with building components defining and/or within the cavity, the method comprising applying a surface coating of a residual insecticide such that respective contacting surfaces of the solid insulation and building component are coated with the insecticide. 10 In the present specification and claims, the term "crawling insect" is used to distinguish from flying insects such as flies and mosquitos and wood eating insects such as termites. The term "crawling insect" is a term of the art and includes any insect that moves via a crawling motion such as cockroaches, ants, 15 fleas, carpet beetles, bed bugs, spiders, silverfish and bird lice. In the present specification and claims, the term "solid insulation" refers to a bulk insulation product that is physically placed into position and is distinct from a loose -fill type of insulation that is blown or sprayed into place. Examples of solid types 20 of insulation include batts, blankets or boards. Batts and boards are supplied as discrete units. Blankets are thinner than batts and are supplied in rolls and are cut to size. Batts and blankets are suitably manufactured from materials such as fibreglass, rockwool, natural wool, natural wool/polyester blends and polyester. The method of the present invention is particularly suited for use with bat type 25 insulation. The method of the present invention is applicable to a cavity in a building structure into which a solid type of insulation is placed. The cavity may be any suitable cavity defined by building components including ceilings, walls and under floors.

5 The cavity may have building components within the cavity such as wall studs and noggins. The building component(s) may be any type of building material and includes 5 masonry, steel, timber, fibreboard and the like. In the present specification and claims, the term "residual insecticide" refers to an insecticide that when contacts a surface, a residual amount of insecticide remains on the surface at a level that is toxic or harmful to a target pest. This distinguishes 10 a residual insecticide from insecticides that do not leave any residue such as volatile sprays and the like. The residual insecticide may be in any suitable form that allows application to a surface. The insecticide may be in liquid form where it may be applied by 15 spraying. Alternatively the insecticide may be in the form of a dust or powder. The insecticide is preferably formulated to be applied in a manner that will not cause a significant amount of insecticide to be absorbed into the substrate. For example, absorbent liquid carriers such as glycols are used for the application of termiticides to timber. In contrast to such a use, it is preferred that the insecticide 20 as applied by the present method remains on the surface rather than being carried into the timber A preferred carrier is water, although amounts of carrier such as glycols may be included in minor amounts, suitably in amounts up to about 40vol%, 30vol%, 25 20vol% and 10vol%. In the present specification and claims the term "essentially aqueous" refers to an aqueous solution where water is the carrier present in excess i.e. greater than 50vol%. The formulation may also include other ingredients known in the insecticide formulations art such as emulsifiers, dyes, stickers and the like. 30 6 The insecticide is preferably a compound having a long lifetime that does not biodegrade, thermally degrade, volatilize or be lost in any other way. Suitably the insecticide is a compound that is stable for at least 5 years, preferably at least 10 years, preferably indefinitely. A particularly preferred insecticide is a compound 5 containing boron and boric acid is particularly suitable. Boric acid being an inorganic compound is not biodegradable. Boron is well known to be toxic to insects. Boron in the form of borates, the salts of boric acid are the most widely used. The most common is the sodium salt 10 which is available commercially under the name Borax. Disodium octoborate tetraydrate is used as a timber preservative to protect timber against termite and fungal attack. In order to be used as a timber preservative, a boron compound must penetrate into the timber. Traditionally boron is applied to green sawn timber under dip-diffusion, pressure diffusion or pressure treatment. Full penetration by 15 diffusion alone can take between two to eight weeks. Alternatively, or in addition to, as mentioned above, the use of carriers such as ethylene glycol are used to allow for easier penetration into a timber surface. Boric acid is considered unsuitable for timber treatment as it does not diffuse or penetrate wood as well as borate. 20 In contrast to this known use of borates for timber treatment in which borates are impregnated into the timber, the surface of a timber building component is coated. It is clearly preferable that there is minimal impregnation such that an insecticidally effective amount remains on the surface of the timber building component. 25 An especially preferred form of liquid application is an aqueous solution of boric acid, suitably a solution between about 5% to about 20%, suitably about 8% to about 15%, and preferably about 11% . As mentioned above, boric acid does not penetrate into timber as well as a borate salt. However, some levels of borate 30 may be tolerated. When boric acid is applied in combination with a borate suitable weight ratios of boric acid to borate are 1:1, 1:0.5, 1:0.25 and 1:0.1.

7 Alternatively, the insecticide may be applied in powder form, in which case, the insecticide generally does not penetrate the surface to any appreciable extent. Thus, when used as a powder, higher levels of borates may be tolerated. 5 Whether the insecticide is applied in powder or liquid form may depend to some extent upon the nature of the cavity to which the insecticide is to be applied. Generally liquid sprays are used for applying to surfaces that are non-horizontal such as walls and cathedral or other sloping ceilings. Powders may be used for 10 application to horizontal surfaces such as ceilings and subfloors. The method of the present invention comprises applying a coating of a residual insecticide in such a manner that each respective contacting surface of a building component and solid insulation is coated with a residual insecticide. The 15 respective surface may be coated in any suitable manner and in any suitable order. In order to simplify the process and reduce time and labour costs, either one of the surface of the solid insulation or the building component is coated and when the other of the building component or the solid insulation is placed in contact, some of the insecticide is transferred from one surface to the other. 20 The insecticide is preferably applied onto the surface of a building component in an open cavity before a solid insulation is placed into the cavity. When the insulation is placed within the cavity at least some of the insecticide is transferred to the surface of the insecticide. In this way, insecticide is located on opposing 25 surfaces of the cavity and insulation. It will be appreciated that an insect crawling in this area will come into contact with either one or both surfaces, thereby causing some insecticide to adhere to the insect's body. This is particularly effective for cockroaches who like to hide and rest in very small areas and prefer both the top and bottom parts of their body to contact a surface. 30 8 According to a further broad form of the invention, there is provided a method for the control of crawling insects in a cavity in a building structure, the method comprising the steps of: applying a coating of a residual insecticide to a surface of a building 5 component in an open cavity in a building structure and placing a solid insulation material into the cavity in contact with the surface of the building component. For wall cavities and subfloors, the cavity is generally enclosed after installation of the insulation. Typically a second application of insecticide is made to the outer 10 surface of the insulation. The cavity is then enclosed with a suitable construction material. Generally, the interior surface of the wall material will contact the insulation surface, thereby transferring insecticide to the inner wall. It is important for optimal insulation that batts are installed such that they completely fill the cavity. 15 In the case of a ceiling, the insulation is usually not enclosed, in which case a second application to the outer side of the solid insulation may not be necessary, although of course may be conducted. 20 The method of the invention is suitably conducted during construction of a building. In this way, when cockroaches are introduced into the building, as they invariably will be, upon entering cracks and voids they will almost inevitably contact the treated insulation, thereby preventing establishment of a breeding colony. 25 However, it may be appreciated that the method may also be applied during renovations or in any other situation where insulation is replaced or retrofitted.

9 Alternatively or in addition to, a suitable residual insecticide may be applied to the solid insulation before the insulation is placed into the open cavity. Suitably at least some of the residual insecticide on the solid insulation will transfer upon contact to the inner surface of the cavity. A preferred solid insulation for this form 5 of the invention is a batt. An advantage of this form of the invention is that application of the insecticide need not be conducted at the construction site, although such a step is within this aspect of the invention. The solid insulation may be suitably wrapped or packaged that prevents loss of the insecticide from the surface during storage and transport. 10 According to a further broad form of the invention, there is provided a packaged solid insulation having a residual insecticide applied to the surface thereof. Suitably the insulation is a batt such as a fibreglass batt. The solid insulation may 15 be sprayed with a liquid or dusted with a powder. Suitably both major surfaces of the insulation are treated. Preferably, when the insulation is a bat, all six surfaces are treated. When the insulation is a roll that in use is to be cut to size on site, it is of course not possible to pre-treat a cut surface. In this case, during installation, it is desirable that either the cut face is treated on site, or alternatively that surface 20 of the cavity that is to come into contact with the surface on treatment may be coated with the insecticide prior to installation of the insulation. Suitably, the solid insulation is an insect resistant. The solid insulation may also be a solid cellulose, wool or other natural product material that would normally 25 have an insecticide evenly dispersed throughout the insulation. For example surface treatment of wool batts is contemplated by this form of the invention. According to a further preferred form of the invention there is provided a method for the control of crawling insects in a building structure, the method comprising 30 the steps of providing a solid insulation having opposed major surfaces, applying a 10 coating of a residual insecticide to each major surface and installing the coated insulation into an open cavity of a building structure. EXAMPLES 5 Interior Wall An 11 % boric acid solution in water is sprayed onto all surfaces of a timber or metal internal wall frame so as to wet the surface of the frame. Whilst the frame is 10 still wet, fibreglass insulation batts are inserted in place between the studs. The surface of the batts are then sprayed with the boric acid solution. The wall panels are mounted to the frame as per standard construction methods. It will be appreciated that with this method of application, the entire interior surface 15 of the cavity including the frame, insulation and interior face of the walls have a layer of boric acid coated thereon. Interior Wall 20 Boric acid powder is dusted onto all surfaces of a timber or metal internal wall frame so as to cover the surface of the frame. Fibreglass insulation batts are then inserted in place between the studs. The surface of the batts are then sprayed with the boric acid solution. The wall panels are mounted to the frame as per standard construction methods. 25 It will be appreciated that with this method of application, the entire interior surface of the cavity including the frame, insulation and interior face of the walls have a layer of boric acid coated thereon.

11 Ceiling Boric Acid powder is applied to the surface of a ceiling cavity ensuring that all 5 surfaces including the joists and ceiling lining are covered with powder. Fibreglass insulation batts are installed as per the manufacturer's instructions. Interior Wall 10 Fibreglass bats will be sprayed on all sides with an 11% aqueous solution of boric acid and allowed to dry. The bats are then packaged into packs as per standard practice. The batts are to be installed to an internal wall frame as per the manufacturer's 15 instructions ensuring that the treated surfaces of the bats comes into contact with the frame. If any of the bats need to be cut to size, the cut end of the bat is dusted or sprayed with an 11% aqueous boric acid solution and/or the frame member that is to be contacted with the cut end is sprayed with the solution. 20 Interior Wall Fibreglass batts will be dusted on all sides with boric acid powder. The batts are then packaged into packs as per standard practice. 25 The batts are to be installed to an internal wall frame as per the manufacturer's instructions ensuring that the treated surfaces of the batts comes into contact with the frame. If any of the batts need to be cut to size, the cut end of the bat is 12 dusted or sprayed with an 11% aqueous boric acid solution and/or the frame member that is to be contacted with the cut end is sprayed with the solution. It will be appreciated that this method provides a layer of boric acid between the 5 insulation and the building components in contact with the insulation. It is these narrow crawl spaces between the frame and insulation that crawling insects such as cockroaches inhabit and breed. This may be compared to drilling a hole into an enclosed cavity and applying a spray. Such a method does not and cannot reach each surface of the frame and insulation in a uniform manner. Even a 10 narrow strip of uncoated surface can provide an insect corridor that can allow insects to safely traverse the cavity. It will be appreciated that various changes and modifications may be made to the invention as described and claimed herein without departing form the spirit and 15 scope thereof.

Claims (10)

1. A method for the control of crawling insects in a building structure having at 5 least one cavity containing a solid insulation product in contact with building components defining and/or within the cavity, the method comprising applying a surface coating of a residual insecticide to the solid insulation and/or the building component such that respective contacting surfaces of the solid insulation and building component are coated with the insecticide 10 and the insecticide can be collected on the insect's legs or body as it traverses the coated surface.

2. The method of Claim 1 comprising the steps of: applying a coating of a residual insecticide to a surface of a building 15 component in an open cavity in a building structure and placing a solid insulation material into the cavity in contact with the coated surface of the building component.

3. The method of claim 2, wherein the building component is a wall frame and 20 after installation of the insulation, the insecticide is further applied to the surfaces of the insulation that are not in contact with the building component.

4. The method of any one of claims 1 to 3, wherein the insecticide is applied 25 as a spray in a liquid carrier.

5. The method of claim 4, wherein the carrier is essentially aqueous. 14

6. The method of claim 1, wherein the building component is a ceiling.

7, The method of claim 6, wherein the insecticide is applied as a powder. 5

8. A method for the control of crawling insects in a building structure, the method comprising the steps of providing a solid insulation having opposed major surfaces, applying a coating of a residual insecticide to each major surface and installing the coated insulation into an open cavity of a building structure, 10

9. The method of any one of claims 1 to 8, wherein the residual insecticide comprises boric acid.

10. The method of any one of claims 1 to 9, wherein the solid insulation is a 15 batt.