AU735842B3 - The protection of buildings from subterranean termites - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: TERMIBAR PTY LTD MR IAN DESMOND RITCHIE CULLEN

CO.,

Patent Trade Mark Attorneys, 239 George Street, Brisbane, QId. 4000, Australia.

THE PROTECTION OF BUILDINGS FROM SUBTERRANEAN TERMITES Details of Associated Provisional Applications: PQ2367 DATED 26TH August 1999 The following statement is a full description of this invention, including the best method of performing it known to us.

THE PROTECTION OF BUILDINGS FROM SUBTERRANEAN

TERMITES

TECHNICAL FIELD This invention relates to methods and means for protecting buildings from subterranean termites and has particular relevance to the protection of buildings based on concrete slab foundations.

BACKGROUND ART More than 350 species of termites have been recorded in Australia, about 30 of which achieve economic importance as pests of timberin-service.

With the exception of the drywood termites, all species of economic importance are soil-dwelling (subterranean) and have similar habits. Several of them have a wide geographic distribution.

Subterranean termites may eat timber and timber products or any material containing cellulose, their principal food, and this could include Is the building contents such as furniture, printed materials, fabrics, clothing, S. footwear, packing cases and tools.

Termites can also damage some non-cellulose materials, for example, soft metal, inferior concrete and plastics such as polyethylene piping, building sealants and rigid foam insulation.

Typically, termites form nests in the soil, near ground level in a stump, the trunk of a living tree or other suitable piece of wood. A colony may persist for many years and, as it matures, have a population running into millions.

Attacks by subterranean termites originate from the nest. Wood or timber lying on or buried in the ground may be reached by underground foraging galleries but attack may occur well above ground level either inside the wood or by way of mud-walled shelter-tubes "plastered" on the outside of a structure or item.

Timber resting on an impenetrable substructure may be reached by means of these shelter-tubes or through independent, freestanding columns built by the termites.

In rare cases where a source of permanent moisture, e.g.

leaking plumbing, is available to the termites within the building, subterranean termites can form a nest inside a building without soil contact.

Where barrier systems for termite protection of a building are to be installed, the designer should complete all construction details before works commence. The requirements for an effective termite barrier can then be established for the particular site conditions and any building features necessary to ensure the desired level of protection.

The risk of subterranean termite infestation can be minimised in new buildings by installing barriers during construction. These barriers impede and discourage termite entry into buildings. Termites can build around barriers, but they can then be detected more readily during routine inspections. Bridging or breaching of these termite barriers by subsequent construction or other activities will defeat the protection measures taken.

The severity of termite problems in Australia and elsewhere 15 should make those involved in the building and construction industry very wary of potential legal liabilities as the failure to comply with acceptable standards of construction is likely to lead to actions by dwelling owners S* against them.

Australian Standard No. AS 3660.1 1995 describes and illustrates types of slab foundations which minimise the risk of termite invasion however as is alluded to earlier it is often events and activities which occur after construction that defeat protection measures.

It is an object of the present invention to provide a method of S"providing a visual and/or physical barrier for the purpose of detection of the presence of termites in a structure built on or incorporating a concrete slab.

It is a further object of the present invention to provide formwork and fittings for use in the construction of a slab foundation which incorporates a visual termite barrier.

Further objects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION According to the present invention there is provided an above ground concrete raft foundation for a building including a stepped peripheral footing comprising a substantially vertical riser and a horizontal tread and a floor slab contiguous with the footing, characterised in that an outer portion of the tread of the footing is adapted to extend substantially beyond outer wall cladding erected thereon to thus provide a horizontal barrier which facilitates the visual detection of the presence of subterranean termites.

The tread of the footing extends at least 50 millimeters beyond the building line.

The extending portion of the horizontal tread can be sloped downwardly and outwardly.

BRIEF DESCRIPTION OF THE DRAWINGS o 15 Aspects of the present invention will now be described with S.reference to the accompanying drawings inwhich; Figures 1 to 4 are drawings of slab foundation details endorsed *by the Standards Association of Australia and acknowledged herein as PRIOR ART, and Figure 5 is formwork block out in accordance with one possible S embodiment of the present invention, and Figure 6 is a bracket for securing the formwork of figure 5, and Figure 7 is a sectional view of a monolithic slab foundation t showing the formwork block out and bracket of figures 5 and 6 in place in a foundation, and Figure 8 shows the foundation of figure 7 after the foundation has been stripped and walls and claddings fitted thereto, and Figure 9 shows how a block out former-can be positioned to provide an enlarged inspection ledge at the periphery of a building.

With respect to figures 1 to 4 of the drawings the prior art slab foundation alternatives illustrated have in common an overlap from the foundation footings or pads 1 by foundation slabs 2 with reinforcing details 3 of various configurations. In some instances reinforcing may not be required.

The alternatives illustrated each provide a stepped peripheral edge 4 which determines that the base of the outer walls 5 are set lower than the equivalent of the internal walls 6. These techniques provide provision for anti-termite infestation measures including flashings 7 (see figure 4) and the like.

The treatment by chemicals of areas susceptible to termite invasion is obviously more difficult after construction and one of the keys to effective identification and treatment of a problem is the ability to make visual lo inspections. If a dwelling owner has built or landscaped up to the building line termite detection becomes more difficult.

The present invention provides a solution and aid for visual *.inspections for structures with slab foundations.

With respect to figures 5 to 8'of the drawings the present 15 invention provides methods and means for establishing a horizontal visual el termite barrier around the periphery of a slab foundation. The barrier becomes an external, optionally sloping ledge which is an extension of a conventional foundation detail. The barrier 10 may be a minimum of say 75mm wide and may have an upper surface sloped by say 15 degrees.

The slope commences below weep holes in a convention block/brick construction.

:The barrier 10 has the advantage of adding additional strength to a structure at a marginal increase in cost.

A conventional outer wall ledge 11 and the barrier 10 are formed by a block out former 12 when concrete is poured.

The block out former 12 may be in the form of an elongate foam section secured in place by a bracket 13 which may be suspended to a form board 14 in the manner illustrated. After a concrete pour the bracket can be readily stripped.

The bracket 13 can comprise a formboard mounting strap 13a and an extending arm 13b having a toe-piece 13a which engages with a rebate 12a in the inner wall of the former 12.

With respect to figure 9 of the drawings, an enlarged visual inspection barrier can be formed by the positioning of a substantially Lshaped former generally indicated by arrow 15 at the periphery of a formwork for a foundation.

The barrier 16 formed after a concrete pour extends well beyond the specified building line 17 of a subsequently erected structure.

The former 15 may be temporarily secured by braces 18 and a formboard 19, pegs (not shown) or the like.

The former 15 may be made in shaped or otherwise fabricated l0 or moulded from steel, timber, plastics or the like. The barrier 16 may form or partly form a pavement.

:::Aspects of the present invention have been described by way of S•example only and it will be appreciated that modifications and additions ooooo thereto may be made without departing from the scope thereof, as defined in S. 15 the appended claims.

Claims (3)

1. An above ground concrete raft foundation for a building including a stepped peripheral footing comprising a substantially vertical riser and a horizontal tread and a floor slab contiguous s with the footing, characterised in that an outer portion of the tread of the footing extends at least 75 millimeters beyond a specified building line to thus provide a substantial horizontal barrier which facilitates the visual detection of the presence of subterranean termites. l0

2. A structural foundation as claimed in claim 1 wherein the extending portion of the horizontal tread is sloped downwardly i and outwardly.

3. A structural foundation as claimed in claim 1 and substantially herein described with reference to the accompanying drawings. DATED this 30 th day of April 2001 TERMIBAR PTY LTD 089 033 447) By their Patent Attorneys CULLEN CO. ,l *~e