BEST MODE FOR CARRYING OUT THE INVENTION

[0015] The composite building component 10 shown in FIG. 1 is constructed around a floor supporting timber batten and comprises a support member or joist 11, a noise attenuating member 12 and a fixing member or batten 13 to which a floor board or sheet 14 is secured by means of fastener 15.

[0016] In this example, the joist 11 is wood as is the batten or fixing member 13 and the noise attenuating member 12 is an extruded polymer blend of polyisoprene, natural rubber and butyl rubber having appropriate safety, toxicity and flammability properties and a density of 0.925 gm/cc. It is preferably a closed cell foam. Other noise attenuating materials may also be used.

[0017] The joist 11 is rectangular in cross-section and has planar sides 16, 17, a planar top face 19 and a planar bottom 18. The noise attenuating member 12 has a planar bottom face 20 which sits upon the top face 19 of the joist portion 11. A layer of adhesive may be placed between the top face 19 of the joist and the bottom face 20 so as to bond the noise attenuating member 12 to the batten portion 11.

[0018] The noise attenuating member 12 is of generally rectangular cross-section having a width which, in this instance, is the same as that of the joist portion 11. The noise attenuator 12 has a body portion 21 and optional upwardly extending side walls 22, 23 which define therebetween a channel 24. Optional inwardly directed top flanges 25, 26 of the respective side walls 22, 23 define a restricted entry 27 to the channel 24. A fastening member 28 may be used to secure the member 12 to the support member 11. It will be noted that the head 29 of the fastener 28 is beneath the upper face 30 of the body portion 21—that is, the head 29 is clear of the channel 24.

[0019] In this instance, the batten or fixing member 13 is inverted “T” shape and has a body portion 31 and an upwardly facing fixing portion 32. The body portion 31 is a neat fit in the channel 24 and the fixing member 13 is held in place by the flanges 25, 26. The fixing member 13 could be of “I” cross-section with the flanges 25, 26 located in grooves along the side faces of the “I”. It will be noted that the fastener 15 does not engage the noise attenuating member 12 and that there is no direct connection between the fixing member 13 and the support 11.

[0020] As shown in FIG. 2, the noise attenuating member 100 may be provided as a module of indeterminate length (or in sections) in which a number of through openings 101 have been provided. In this example, the through openings 101 are provided along the longitude centre line 102 and are evenly spaced. In one example, the through openings 101 pass completely through the body portion 21. Each opening 101 is approximately 20 mm in diameter. The openings are spaced apart from one another by about 40 mm (centre to centre). The openings 101 reduce the mask of the noise attenuating member 100 and therefore increase its effectiveness. This modification to the embodiment depicted in FIG. 1 causes a reduction in noise which is reflected in an Impact Insulation Class from 40 I.I.C. up to 64 I.I.C.

[0021] As shown in FIG. 3, a timber batten of the type depicted in FIG. 1 may be provided with regularly spaced through holes 40. These through holes 40 may be used to insert fasteners 41 into an underlying supporting structure such as a timber joist or concrete slab. Note that the head 42 of the fastener 41 is smaller in diameter than the diameter of the through hole 40 and larger in diameter than the opening 43 which is provided in the body portion 21 of the noise attenuator 12. The openings 43 are provided between and in addition to the noise attenuating openings 101 which are depicted in FIG. 2.

[0022] With reference to FIG. 3, it can be seen that a typical timber batten 13 may have a top surface width 44 of about 34 mm and a bottom surface width 45 of about 40 mm. The width 46 of the noise attenuator 12 is about 50 mm and its overall height 47 is about 32 mm. The thickness of the side wall 48 is about 5 mm and the depth of the flange 49 is about 3 mm. Also note that air borne noise may be attenuated by providing an adhesive polymeric tape or strip 60 between the timber batten 13 and the flooring that it supports. Tapes or strips of this type are generally 5 mm thickness or less and need not necessarily span the entire width of the batten 13.

[0023] As shown in FIGS. 4 and 5, the batten and noise attenuator 12 of the present invention may be used in conjunction with a concrete slab 50 or in conjunction with timber joist 51. Either type of substrate (50, 51) may be used in conjunction with optional suspended ceiling assemblies 52.

[0024] The composite batten of the invention has the added advantage of being able to be easily glued to the concrete slab, helping to prevent buckling as the moisture content of the timber flooring changes. The composite batten of the invention would also provide better reduction of footstep noise common in multi-storey buildings with all timber flooring.

[0025] Apart from the noise attenuating aspect of the floor batten, the composite building component of the invention will provide a cushioning effect.

[0026] Floors constructed according to the present invention have been tested by Australia's CSIRO (Commonwealth Scientific and Industrial Research Organisation). A complete report on the impact sound insulation qualities of the present invention are contained in a publicly available CSIRO report (Measurement No. TIi401). The results of that report indicate that the teachings of the present invention provide a fixed flooring system achieving an I.I.C. rating of about 50 which rating is obtained with a timber only flooring with no carpet, underlay, tile, vinyl flooring or other covering. I.I.C. refers to the Impact Insulation Class, a single number index of performance which can be used for comparing floor/ceiling assemblies for general building design purposes. The index is calculated from measured values of the (normalised) third-octave impact sound pressure levels. The procedure for calculating I.I.C. number is specified by the American Standard ASTME989-89. As such, fixed flooring systems made in accordance with the teachings of the present invention are about to be the only ones in the world to have achieved a rating of above I.I.C. 50.

[0027] Various modifications may be made in the shape, configuration and composition of the members which comprise the composite building component without departing from the scope and ambit of the invention.