H \ejl\ntenvoveiNRPonblDCC\EL\6x669_ I dc- I3XA/2014 "Moulded concrete construction panel system" Cross-Reference to Related Applications 5 The present application claims priority from Australian Provisional Patent Application No 2006906338 filed on 14 November 2006, the contents of which are incorporated herein by reference. Field of the Invention 10 This invention relates, generally, to the caulking of joints, and more particularly to a caulking strip for caulking of joints between construction panels. The panels are preferably moulded concrete panels, more particularly, tilt-up panels which are poured on site and, once set, raised and located in position. The invention relates also to a panel system. 15 Background to the Invention At present, tilt-up building construction panels are caulked using a caulking infill compound which is pumped into the panel joints after they are erected. This procedure is very expensive 20 and time consuming and must normally be carried out by a specialised tradesperson. A further disadvantage is that the caulking compound or material undergoes shrinkage as it dries and this can affect its ability to seal the joint effectively and make it weather-proof. This problem often requires that panel joints be re-caulked at a later date which in turn creates additional cost and inconvenience. 25 Summary of the Invention In accordance with the present invention, there is provided a moulded concrete construction panel system comprising: a pair of moulded concrete construction panels arranged in 30 aligned spaced relationship to define a gap between facing sides of the panels; and at least one caulking strip, wherein the caulking strip has an elongate body member defining a head portion and a stem portion extending from the head portion, the stem portion being received between the two panels; and a plurality of engaging formations, at least some of H-I:ej\JnerwoveinMR~orIb\DCC\EJL\65SS669_l.doc- 13/08/2114 IA which are of a resiliently flexible material, projecting laterally from the stem portion to abut substantially sealingly against said facing sides of the panels between which the body member is received the stem portion being bifurcated to form at least two limbs, each limb carrying an array of the projections, at least one of the projections on each of the limbs 5 being an extended projection having a tapered leading end and extending laterally further than the remaining projections on the respective limb, wherein said extended projections are received in and abut against corresponding receiving grooves in said facing sides of the panels such that the caulking strip forms a weather-proof seal between the panels. 10 In one example, there is provided a caulking strip for caulking a joint between components, the strip including an elongate body member defining a head portion and a stem portion extending from the head portion to be received between the two components; and a plurality of engaging formations, at least some of which are of a resiliently flexible material, projecting laterally from the stem portion to abut substantially sealingly against 15 facing sides of the components between which the body member is received wherein the stem portion is bifurcated to form at least two limbs, each limb carrying an array of the projections, at least one of the projections having a tapered leading end and extending laterally further than the remaining projections. 20 According to one example of the invention, there is provided a caulking strip for caulking a joint between components, the strip including an elongate body member defining a head portion and a stem portion extending from the head portion to be received between the two components; and a plurality of engaging formations, at least some of which are of a resiliently flexible material, projecting laterally from the stem portion to abut substantially sealingly 25 against facing sides of the components between which the body member is received. The body member may be a one-piece unit of a resiliently flexible material. The stem portion may be bifurcated to form at least two limbs, each limb carrying an array of 30 the projections, at least one of the projections extending laterally further than the remaining projections. It will be appreciated that the limbs are mirror WO 2008/058311 PCT/AU2007/001653 2 images of each other. The head portion may define abutment surfaces which abut against the components, the abutment surfaces being arranged on opposite sides of the stem portion. According to second aspect of the invention, there is provided a panel system 5 which includes a pair of panels arranged in aligned spaced relationship to define a gap between facing sides of the panel; at least one caulking strip, as described above, received in the gap to form a caulked joint. 10 Preferably, the system includes a pair of the caulking strips, the strips being arranged in facing relationship at opposed ends of the gaps. An edge of each panel may be shaped to accommodate a part of the head portion of the body member of the at least one caulking strip. The facing side of each panel may define a receiving zone to receive at least one of the engaging formations of the 15 caulking strip. A fire-retardant material may be received in each caulking strip. More particularly, the fire retardant material may be received in a slot defined between the limbs of the stem portion of the caulking strip. 20 Brief Description of the Drawings An embodiment of the invention is now described by way of example with reference to the accompanying drawings in which: Fig. 1 is a fragmentary exploded perspective view of a caulked panel system in accordance with an embodiment of the invention; 25 Fig. 2 is a cross-sectional plan view taken through the panel system shown in Fig. 1; and Fig. 3 is a plan view of an embodiment of a caulking strip used to caulk the panel joint shown in Fig. 1. 30 Detailed Description of Exemplary Embodiment In Figs. 1 and 2 of the drawings, reference numeral 10 generally designates an embodiment of a panel system. The panel system 10 comprises a pair of concrete building panels 11, 12 which are arranged in aligned spaced relationship with their facing sides 13, 14, respectively, forming a gap 30. 35 In this embodiment, the gap 30 between the facing sides 13, 14 of the panels 11, 12 respectively, is caulked by means of two elongate caulking strips 15, 16, also in WO 2008/058311 PCT/AU2007/001653 3 accordance with an embodiment of the invention, inserted in opposite ends of the gap 30. Referring now to Fig. 3 of the drawings one of the caulking strips 15 is described in greater detail. It will be appreciated that the other caulking strip 16 is 5 identical. The caulking strip 15 is approximately T-shaped in cross-section and has a head portion 17 and a stem portion 18 projecting centrally from one side of the head portion 17. The stem portion 18 carries laterally projecting engaging formations in the form of ribs 19, 20, 21, the purpose of which will be described below. The stem portion 18 10 is bifurcated and is formed to have spaced axially extending limbs 18', 18" which are separated by an open-ended slot 22. The slot 22 allows the leg portions 18' 18" to be squeezed together so as to compress the stem portion 18 when it is inserted into the gap 30 between the panels 11, 12. The limbs 18', 18" are mirror images of each other and each limb 18', 18" carries an array of the ribs 19, 20, 21. 15 Each of the ribs 19, 20, 21 is approximately saw-tooth shaped in vertical cross section having a tapered leading end and a blunt trailing end. The rib 19 has a lateral dimension greater than that of each of the other ribs 20, 21. The head portion 17 of the strip 15, 16 has a concave outer face 25 and a tapered inner face 26 from which the stem portion 18 projects. The inner face 26 defines a pair 20 of abutment surfaces 32, the surfaces 32 being arranged on opposed sides of the stem portion 18. As shown in Fig. 2 of the drawings, each of the facing sides 13, 14 of the panels 11, 12 has moulded therein a pair of spaced, parallel longitudinally extending grooves 28. Each groove 28 is shaped approximately complementarily to the shape of an 25 associated rib 19 of each strip 15, 16. Thus, when the strips 15, 16 are fully inserted in position, the ribs 19 are received in a locking manner in their associated grooves 28. Each edge 34 (Fig. 2) of the facing sides 13, 14 of the panels 11, 12 is bevelled so as to form a bearing surface against which one of the abutment surfaces 32 if the head portion of the relevant strip 15, 16 abuts in a substantially sealing manner. The 30 head portion 17 thus lies substantially flush with surfaces of adjacent panels 11, 12. In this embodiment, with the concave outer face 25 of the head portion of each strip 15, 16, a shallow recess extends longitudinally along the join. When the strips 15, 16 are fully inserted into the gap 30, the ribs 20, 21 are slightly deformed (as can be seen in Fig. 2) and make tight frictional engagement with 35 the sides 13, 14 of the panels 11, 12. It will of course be appreciated that the ribs 19 will similarly deform but once they align with their associated complementarily shaped WO 2008/058311 PCT/AU2007/001653 4 grooves 28, they spring outwardly and lockably engage with their associated grooves 28. The sealing contact made between the outer surfaces of the stem portion 18 of each strip 15, 16 and the sides 13, 14 of the panels 11, 12 is effective to render the joint so formed weather-proof. It will be appreciated that each strip 15, 16 is formed of a 5 resiliently flexible material, more particularly, an elastomeric material such as a suitable rubber or rubber like material. This enhances the sealing action of each strip 15, 16. If desired, the slot 22 of each strip 15, 16 is filled with a fire retardant material to increase the fire proof rating of the panel system 10. 10 It will be appreciated that the panel system 10 may be used to caulk panel joints for any type of concrete panel construction, e.g. large concrete water tanks. It is an advantage of the present invention that the shape and dimensions of the strips 15, 16 inhibits shrinkage when inserted into the joint 30. It is another advantage that, in the event of a strip 15, 16 being damaged, it can be readily removed and 15 replaced with a new strip 15, 16. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as 20 illustrative and not restrictive.