Patent Application
20070175159
The present invention relates to a lightweight panel for use as an outer layer of a dwelling wall and a dwelling wall constructed using such lightweight panels.
Many conventional dwellings have brick veneer walls that typically comprise a structural frame having an outer layer of bricks and an inner layer of plasterboard liner. In recent years such walls have been constructed with insulation foil disposed therein. The use of the insulation foil increases the thermal resistance of the dwelling wall and results in a far more energy efficient home. Whilst many home builders and the general public at large are becoming more aware of the advantages of energy efficient homes, their cost of construction are still quite considerable, particularly due to the labour and materials handling required.
The brick veneer is a form of cladding which covers the load bearing wall and generally provides an aesthetically pleasing exterior finish. Because of thermal expansion and contraction (and indeed even expansion of bricks with age) about every 50 feet (15 meters) in a brick veneer wall it is necessary to provide a control joint. This is a vertical gap in the bricks up to 15 mm in width which is filled with a compressible sealing material. Between the bricks themselves is a layer of mortar which bonds to the bricks and thus binds all the bricks together. The cost of conventionally laid bricks is relatively high because of the need for skilled (and therefore highly paid) bricklayers and the need for mortar with its inherent delays involved in mixing, laying and subsequent clean up.
The genesis of the present invention is a desire to provide a lightweight panel that can be used in the construction of a dwelling wall that has a thermal resistance greater than that of a brick veneer wall, and is relatively simple to construct.
According to a first aspect the present invention there is disclosed a cladding and insulating veneer arrangement fixed to a load bearing subwall, said arrangement comprising a vertically and horizontally extending stack of substantially vertically aligned panels which are loose fixed without bonding jointing material between the panels, and retaining clips extending between said panels and the subwall.
According to a second aspect the present invention there is disclosed a method of erecting a cladding and insulating veneer arrangement for a load bearing subwall, said method comprising the steps of:
(i) positioning a plurality of substantially vertically aligned panels in edge abutment to form a row,
(ii) loose fixing said panels without bonding jointing material between the panels,
(iii) utilizing retaining clips extending between said panels and said subwall to retain said panels in said row, and
(iv) repeating step (i) for a vertically adjacent row.
According to a third aspect the present invention there is disclosed a lightweight panel for use in the abovementioned cladding and insulating arrangement, said panel being formed substantially from concrete which comprises cement, sand, lightweight aggregate, superplasticiser and water; having a density in the range of 500-1500 kg/m3; and having an inter-engagement means to enable said panel to be loose fixed with a plurality of like panels in a vertically and horizontally extending stack of said panels, and said inter-engagement means being shaped to permit engagement with a retaining clip which permits said stack of panels to be retained adjacent a subwall from which said retaining clip extends.
a and 4b depict perspective views of corner lightweight concrete panels used in the construction of the dwelling wall shown in
The inner layer of dwelling wall 1 comprises of conventional plasterboard liner 4, which is typically about 13 mm thick, attached to the structural frame of studs 2 and noggings 3.
The outer layer of dwelling wall 1 comprises of a plurality of lightweight concrete panels 5a, 5b, 5c, 5d and 5e. Each standard panel 5a and corner panel 5b is about 600 mm×300 mm×50 mm, whilst smaller corner panel 5c is about 300 mm×300 mm×50 mm, however this size is not critical. What is of substantial economic importance is that each panel is of a size equivalent in wall surface area to many bricks and can be much more quickly and conventionally lifted, handled and placed in position than the many bricks of equivalent wall surface area.
All panels 5a-c have a tongue 6a along their upper horizontal extent and a groove 7a extending along their lower horizontal extent, for horizontal stacked engagement in tongue and groove relationship with other like panels 5a-c. The standard panels 5a also have a tongue 6b and groove 7b disposed oppositely to each other along their vertical edges, for vertical abutment in tongue and groove relationship with other like panels 5a-c.
The corner panels 5b and 5c vary on the vertical edges, in that the groove 7b is replaced by a flat face 7c. It should be noted that in
Panel clips 8 secured to studs 2 at 450-600 mm spacing by nail or screw fasteners, are used to secure panels 5a-c to the structural frame. Each panel clip 8 has a back portion 9 adapted to sit flush against the stud 2 to which it is secured. The ledge portion 10 which projects from back portion 9, is adapted to engage with adjacent lightweight panels 5a-c at the junction of their substantially horizontal respective tongue 6a and groove 7a.
In this way the panels are able to be stacked horizontally in a row and vertically with one row above another. As each panel is placed in position it is kept in place by means of one of the clips 8 until the next row of panels is positioned above the previous row. In this way no skilled labour such as a bricklayer is required. Furthermore, the clips 8 are hidden from view and thus provide a concealed temporary fixing.
Furthermore, the inter-engagement of the tongues 6 and grooves 7 provides an overlap between adjacent panels 5 which is sufficient to seal against the ingress of wind and/or moisture. Since the panels 5 are loose fitted in the stack the panels 5 can move relative to each other and the clips 8 to accommodate thermal expansion and contraction. This is to be contrasted with conventional brick veneer construction where a bonding jointing compound such as mortar actually binds each brick to its adjacent bricks. It follows that because of this loose fitting of the panels 5 no control joints are required.
Concertina (or zig-zag) foil batts 11 are preferably disposed within the structural frame between the inner layer of plasterboard liner 4 and outer layer lightweight concrete panels 5a-e. One suitable type of batt 11 is the commercially available RENFOIL aluminium concertina batt.
Also a second layer of foil sheet 12, as shown in
The lower portion of wall 1 has an apron 14 which extends downwardly from a 100 mm×75 mm hardwood plate 15. The apron 14 does not extend to the ground line. A mesh 17, preferably of stainless steel covers the gap between apron 14 and the ground, and is affixed to a pine fixing plate 18. A flashing 16 is placed between the bottom row of panels 5 and the plate 15.
The lightweight panels 5a-c are manufactured by moulding and in this embodiment are preferably moulded to a thickness of about 50 mm. Once the panels are moulded, if desired they each can have a polystyrene sheet 13 of about 8-12 mm adhered to their back. However, this is not essential and in many circumstances undesirable since the panels with the polystyrene sheet 13 are much less robust and are more difficult to handle than the panels 5 without the polystyrene sheet 13. The panels are then cured in racks. The resulting thickness of the panels in this embodiment is about 60 mm. In an alternative embodiment, the polystyrene sheet 13 may be affixed to the panel during moulding/casting.
The concrete mix used to make the panels 5a-c is extremely lightweight. Generally speaking, “lightweight” is typically regarded as low-density concrete of less than 2100 kg/m3 using lightweight aggregate (for example scoria) or (polystyrene beads) which are preferably uncoated with any chemicals.
In the present invention the concrete mix used to make the panels has a density substantially less than 2100 kg/m3 and preferably in the range of 500-1500 kg/m3. More preferably the density of the concrete mix is in the range 700-1200 kg/m3. A density of 1100 kg/m3 is particularly preferred. The concrete mix comprises cement, sand, lightweight concrete aggregate, a high range superplasticiser and water.
Examples of suitable mixes are shown in the table below.
Whilst in the abovementioned examples the cement used is General Purpose Cement (Type GP), other types of cement such as High Early Strength Cement (Type HE), or blended cements including slag or fly ash blends may be used.
In the abovementioned examples, the sand weights are measured as “saturated, surface dry”.
In the abovementioned examples the preferred proportion of superplasticiser is 0.8% of cement by weight, but may vary from 0.5% to 1.5%. The preferred proportion of 0.8% is based on using the commercially available Sika ViscoCrete®-5 superplasticiser. In other embodiments other brands of superplasticiser may be used. Carbosylic ether polymer is also a suitable superplasticiser.
In the abovementioned examples water quantity is designed to achieve a water/cement ratio in the range of 0.30-0.35 or 0.3-0.4 by weight of cement. This low water/cement ratio is used to optimise concrete strengths and to suit compaction of the concrete.
One advantage of constructing a dwelling wall utilising lightweight concrete panels as described above, is that the wall will have a thermal resistance at least twice that of a conventional brick veneer wall incorporating foil insulation, thereby making the dwelling more energy efficient. A further advantage of the dwelling wall utilising such lightweight panels is that its weight/mass is considerably less than a brick veneer wall and may be constructed faster and with less skilled labour than a brick veneer wall, thereby reducing the overall cost for constructing the dwelling.
A further advantage is that the concrete panels as described above have suitable aesthetic appeal and look somewhat like a sandstone finish. This is achieved by placing sand in the bottom of the mould (not illustrated) in which the panels 5 are cast. This bottom surface becomes the front face of the panel and the sand bonds with the concrete as the concrete sets. The panels thus formed also have a high impact resistance and good moisture resistance.
Turning now to
The clip 108 has a hook shaped tip which mates with the horizontally extending groove 6a of the panel 5. The vertical base of the clip 108 is secured to the subwall 102 in any convenient fashion using power nails, adhesives, or the like.
It is not essential that the panels 5 be provided with a tongue and groove jointing arrangement. Instead the panels 5 can be provided with a groove 107 that extends entirely around the edge of the panel. As seen in
The panels 5 of
The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the building arts, can be made thereto without departing from the scope of the present invention.
The term “comprising” and its grammatical variations as used herein is used in the inclusive sense of “having” or “including” and not in the exhaustive sense of “consisting of”.
| Number | Date | Country | Kind |
|---|---|---|---|
| 528 803 | Oct 2003 | NZ | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10727564 | Dec 2003 | US |
| Child | 11566962 | Dec 2006 | US |
