AU2019236729A1

AU2019236729A1 - Cladding panels

Info

Publication number: AU2019236729A1
Application number: AU2019236729A
Authority: AU
Inventors: Richard Vernon Lindsay
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2021-04-15

Abstract

A cladding panel is disclosed. The cladding panel comprises a rammed earth portion having a first face, and a second face, the second face disposed opposite the first face to define a first thickness of the rammed earth portion. A sealant is applied to the second face of the rammed earth portion. The cladding panel further comprises a supporting portion having a third face and a fourth face, the third face disposed opposite the fourth face to define a second thickness of the supporting portion. The third face of the supporting portion is coupled to the second face of the rammed earth portion, the fourth face of the supporting portion is configured to be connected to a structure to be clad, and the first face of the rammed earth portion forms an exposed surface of the cladding panel. The rammed earth portion exhibits relatively low linear shrinkage. 1/7 100 Fig. 1B 160 110 Fig.lA 100 175 135 160 19010 165 170 125 130 Fig.1B

Description

1/7

100

Fig. 1B

160 110

Fig.lA

100 175 135

160 19010 165 170 125

130

Fig.1B

"Cladding panels"

TECHNICAL FIELD Disclosed embodiments relate generally to cladding panels for cladding a structure, such as a wall. In particular, disclosed embodiments relate to cladding panels comprising rammed earth portions, and methods of manufacturing said panels.

BACKGROUND Cladding is used in the building and construction industry to cover structures such as walls, pillars, and facades. Cladding may be installed to improve the aesthetics and/or the environmental performance of a structure, and to generally protect the structure. For example, the facades of buildings are commonly clad to protect and hide their concrete and steel superstructures from the weather and passers-by. Cladding may also provide thermal and/or acoustic insulation, which may improve the building's energy efficiency as well as the comfort of its occupants. Cladding is available in panel form for ease of transport and installation, and may be installed internally as well as externally.

Some cladding products comprise materials which have low resistance to fire. For example, to reduce weight, some cladding products comprise a lightweight plastic core sandwiched by aluminium faces. Furthermore, when used externally, some cladding may weather in an unattractive way, compared to more natural materials such as brick, timber, or stone.

It is desired to address or ameliorate one of more shortcomings or disadvantages associated with present cladding panels, or to at least provide a useful alternative thereto.

SUMMARY Some embodiments relate to a cladding panel, comprising: a rammed earth portion having a first face, and a second face, the second face disposed opposite the first face to define a first thickness of the rammed earth portion; a sealant applied to the second face of the rammed earth portion; a supporting portion having a third face and a fourth face, the third face disposed opposite the fourth face to define a second thickness of the supporting portion; and wherein the third face of the supporting portion is coupled to the second face of the rammed earth portion, the fourth face of the supporting portion is configured to be connected to a structure to be clad, and the first face of the rammed earth portion forms an exposed surface of the cladding panel; and wherein the rammed earth portion exhibits relatively low or nil linear shrinkage.

The rammed earth portion may comprise a mixture of an aggregate, a sand, water, and a cement binder. The aggregate may comprise minus crushed rock. The rammed earth portion may comprise a minimum of 30% sand. The rammed earth portion may comprise a maximum of 80% aggregate.

In some embodiments, the rammed earth portion may exhibit relatively low plasticity

. The rammed earth portion may be non plastic.

A sealant may be applied to one or more of: the first face of the rammed earth portion, the third face of the supporting portion and the fourth face of the supporting portion. The supporting portion may comprise a plywood board.

The first thickness of the cladding panel may be approximately 25mm. The second thickness may be approximately 18mm.

Some embodiments relate to a cladded structure comprising a plurality of the described panels, wherein the first faces of the plurality of panels collective form a facade of the cladded structure.

Some embodiments relate to a method for manufacturing a cladding panel, the method comprising: forming a rammed earth portion of the cladding panel in a mould, the rammed earth portion having a first face, and a second face, the second face disposed opposite the first face to define a first thickness of the rammed earth portion, wherein the rammed earth portion exhibits relatively low or nil linear shrinkage; releasing part of the mould to expose the second face of the rammed earth portion; applying sealant to the second face; providing a supporting portion having a third face and a fourth face, the third face disposed opposite the fourth face to define a second thickness of the supporting portion; coupling the third face of the supporting portion to the second face of the rammed earth portion to form the cladding panel; and releasing the cladding panel from the mould.

The method may further comprise, after releasing part of the mould to expose the second face of the rammed earth portion and before applying the sealant, allowing the rammed earth portion to dry.

In some embodiments, forming the rammed earth portion may comprise: preparing the mould, the mould having a body defining a cavity having a depth and a width, corresponding respectively to a length and thickness of the rammed earth portion; blending an aggregate, water, and a cement binder to form a mixture; placing and compacting consecutive layers of the mixture in the cavity to a first density until the cavity is filled; and drying the mixture in the mould.

The mixture may further comprise a water-repellent or waterproof admixture.

The first depth may be at least approximately 100mm. The first depth may be approximately 150mm.

Some embodiments relate to a cladding panel produced by the described method.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments are described in further detail below, by way of example, with reference to the accompanying drawings, in which: Fig. 1A is a side view of a cladding panel for cladding a structure, according to some embodiments; Fig. 1B is a detail view of the panel of Fig. 1A; Fig. 2 is a process flow diagram of a method of manufacturing a cladding panel, according to some embodiments; Fig. 3 is a perspective view of the panel of Fig. 1A; Fig. 4 is a perspective view of a cladded structure comprising a plurality of the cladding panels of Figure 1A;

Fig. 5 is a section view of a cladded structure comprising a plurality of the cladding panels of Figure 1A, and a first coupling mechanism, according to some embodiments; Fig. 6 is a section view of a cladded structure comprising a plurality of the cladding panels of Figure 1A, and a second coupling mechanism, according to some embodiments; Fig. 7 is a section view of a cladded structure comprising a plurality of the cladding panels of Figure 1A, and a third coupling mechanism, according to some embodiments.

DETAILED DESCRIPTION Rammed earth as a building material has a long history of human use, including for walls and habitable buildings. Advantageously, a rammed earth structure has high thermal mass, which can have a positive effect on the energy efficiency of the structure and the thermal comfort of its occupants. Rammed earth also has good fire resistance and sound absorption properties, and has an attractive, natural finish.

Compared to a wall made of concrete, or a steel-frame or timber-frame wall, a rammed earth wall generally has to be made considerably thicker to provide adequate structural performance. This thickness results in a high weight, which limits the use of rammed earth walls to low-rise structures.

Disclosed embodiments relate generally to cladding panels for cladding a structure, such as a wall. In particular, disclosed embodiments relate to cladding panels comprising rammed earth portions, and methods of manufacturing said panels.

Figs. 1A and 1B show a cladding panel 100, according to some embodiments. The cladding panel 100 comprises a rammed earth portion 110 or layer having a first face 125, and a second face 130, the second face 130 disposed opposite the first face 125 to define a first thickness 135 of the rammed earth portion 110. As shown, the rammed earth portion 110 comprises a first length 115 and a second length 120, in addition to the first face 125 and the second face 130.

The cladding panel 100 comprises a supporting portion 160 having a third face 165 and a fourth face 170, the third face 165 disposed opposite the fourth face 170 to define a second thickness 175 of the supporting portion 160. The third face 165 of the supporting portion 160 is coupled to the second face 130 of the rammed earth portion 110. The fourth face of the supporting portion 160 is configured to be connected to a structure (Figure 4) to be clad, and the first face 125 of the rammed earth portion 110 forms an exposed surface of the cladding panel 110.

The cladding panel 100 further comprises a sealant 190 applied to the second face 130 of the rammed earth portion 110. The sealant 190 is configured to seal and strengthen the second face 130 of the rammed earth portion 110 to allow improved coupling of the rammed earth portion 110 to the supporting portion 160. For example, the sealant 190 may mitigate the chance of loose particles compromising the strength of the coupling.

In some embodiments, the sealed second face 130 of the rammed earth portion 110 is coupled to the third face 165 of the supporting portion 160 using an adhesive. However, it will be appreciated that any suitable coupling means may be employed as elaborated on below.

The cladding panel 100, when used to clad a structure such as a wall, provides a similar appearance to a conventional rammed earth wall without the same weight or volume. For example, conventional rammed earth walls used for a wall of a single-storey house may have a thickness in the range of approximately 300mm to 450mm. By comparison, the panel 100 may, in some embodiments, have a thickness in the range of approximately 30mm to 150mm.

The rammed earth portion 110 may comprise a mixture of grained particulate material (aggregate), sand, a cement binder and water. The mixture may further comprise a water-repellent or waterproof admixture. In some embodiments, the mixture is relatively evenly blended together to produce a mouldable mixture when "wet". The mouldability of this mixture can be adjusted by adjusting the ratios of its constituents, before shaping it in a mould to a desired shape, compacting it, and drying it to remove at least some of the moisture for it to set in the desired shape as a "dry" relatively non plastic mixture.

Care should be taken to select appropriate ratios of the constituents in order to find a suitable balance between the mouldability of the "wet" mixture and the strength and aesthetics of the "dry" mixture. The amount of shrinkage as the mixture dries may be affected by the properties of the aggregate selected. For example, an aggregate with too high a Plastic Index % (PI), and/or too much clay, may result in higher shrinkage. Furthermore, the amount of moisture in the wet mixture may also have an effect on the amount of shrinkage as the mixture dries, while the temperature and humidity may also have an effect on the rate of moisture evaporation/drying.

In some embodiments, the dry mixture exhibits the following performance characteristics.

• Minimum unconfined compressive strength = about 9MPa • Linear shrinkage= relatively low to Nil/0%, for example, 1% to 0% • Plastic index (PI) = relatively low to Nil/0% ("non-plastic"), for example, less than 5.

In some embodiments, the dry mixture may contain up to organic matter. However, in some embodiments, organic matter is limited to between 0% to 15% for aesthetic purposes.

In some embodiments, the dry mixture has relatively low plasticity, for example, less than about 5.

In some embodiments, the mixture is configured such that the consistency limits (also known as Atterberg limits) of constituents of the mixture for the rammed earth portion 100, such as the aggregate, cement, and sand, comply with Australian Standard AS 1289.3. In some embodiments, the compaction and density of the dry/moisture content relation using modified compactive effort are configured to comply with AS 1289.5, Method 5.2.1.

In some embodiments, the unconfined compressive strength of the compacted materials are configured to comply with AS 1141.51, Method 51, wherein test samples are to be retained in the mould for 12 hours and air cured in an open environment for 7 days.

In some embodiments, conformance tests, including the characteristic adjusted compressive strength test, may be conducted as specified in CSIRO Bulletin 5, Fourth Edition, Appendix E - Method For Determining Compressive Strength, wherein test samples are to be taken, compacted in a 90mm diameter x 200mm high cylinder, and retained in the mould for 12 hours and air cured in an open environment for a minimum of 7 days. The evaluation criteria is as per CSIRO Bulletin 5, Table 2.2.

The ratios of the constituents are chosen to create a substrate matrix that reduces or eliminates shrinkage, and/or maximises the density of the mixture. Examples of ranges of appropriate ratios of the constituents providing the performance characteristics are shown in Table 1.

Table 1

Constituent Ratio (by volume) Aggregate 14mm minus-sized Class 3 Maximum 80% crushed rock Sand 2mm-5mm washed sharp sand About 0-30% (may depend on makeup of aggregate) Cement Portland grade cement About 5% - 15% Water-repellent or Silane or siloxane based, At manufacturer's waterproof admixture "Plasticure" by Tech-Dry recommended rate; refer Building Products manufacturer's data sheet Water Filtered water About 6% to 10%, for example, 8%

In some embodiments, the aggregate comprises a minus-sized crushed rock with a nil linear shrinkage characteristic and a nil Plastic Index characteristic. The aggregate may comprise sharp, shattered stone pieces. Each stone piece may range in size between approximately 12mm to approximately 16mm. Minus-sized crushed rock, which may alternatively be referred to as minus rock, is a gravel product comprising crushed rock of a specified size mixed with smaller pieces ("fines") and dust. For example, 14mm minus crushed rock comprises crushed rock pieces of 14mm diameter, smaller pieces of crushed rock, and dust.

By comparison, "clean" crushed rock is a gravel product that has had the fines and dust removed so that essentially only the larger pieces of rock remain. The adjoining rock pieces are more likely to have larger gaps in-between, meaning that when a compacting force is applied to the product, the pieces are more likely to shift relative to each other. All else being equal, this means clean rock products offer lower compaction resistance than minus rock products. The smaller pieces in a minus rock product also improves the ability of the product to resist compaction when a compacting force is applied, as the smaller pieces can fill or reduce the size of the gaps between adjoining larger pieces. This also reduces the permeability of the product, for example with regards to moisture. The proportion of the gaps to the particles is expressed as the void ratio.

In some embodiments, a Class 3 crushed rock mix in accordance with the VicRoads Standard Specifications is used to contribute a minimum plasticity and strength to the rammed earth portion 110. In some embodiments, a Class 3 equivalent crushed rock mix may be used, comprising a well-graded road base aggregate, wherein the aggregate comprises rock pieces in the range of approximately 12mm to approximately 16mm. By way of example, a Class 3 crushed rock containing crushed concrete must meet the following specifications: • Liquid Limit % (max) = 35 • Plasticity Index (range) = 0 to 10 • California Bearing Ratio (%) (min) = 80 • Maximum Percentage of Supplementary Materials permitted = 15%

Adding the water-repellent or waterproof admixture, such as Plasticure, provides the earth mixture with reduced water absorption and efflorescence. This may help prolong the strength or appearance of the rammed earth portion 110 when dried. This may also slow the curing process, which may aid in reducing or eliminating shrinkage.

When the mixture has been compacted and left to dry, the loss of moisture may cause the mixture to contract or shrink on itself. If there is too little moisture in the mixture, and/or the rate of moisture evaporation/drying is too high, the mixture is more likely to crack as it dries. The aspect ratios of the rammed earth portion 110 may also contribute to the likelihood and extent of cracking as the mixture dries. Generally, cracking affects the strength of the rammed earth portion 110; nevertheless, some micro-cracks are to be expected and are generally acceptable. However, larger, visible cracks in the rammed earth portion 110 are less acceptable, and also compromises the aesthetics of the panel 100.

Figure 2 is a process flow diagram demonstrating embodiment method 200 of manufacturing a cladding panel 100, according to some embodiments.

The rammed earth portion 110 is formed using a formwork system, as at 210. The formwork typically comprises a mould having a body defining a cavity with dimensions which correspond to the first length 115, second length 120, and first thickness 135 of embodiments of the rammed earth portion 110. Specifically, the cavity has a depth and a width which corresponds respectively to the first length 115 and the first thickness 135. In some embodiments, the mould is capable of disassembly into separate pieces, to allow the release and/or drying of the rammed earth portion 110 to be controlled in a staggered process.

At 220 to 260, consecutive layers of the mixture are placed and compacted in the cavity to a first density, until the cavity is filled. A relatively flat finish is applied to the filled cavity to create a relatively smooth face. In some embodiments, the first density is between approximately 1800kg/m3 and 2500kg/m3. For example, the first density may be approximately 2100kg/m3.

Each of the layers may be applied in depths of approximately 100mm to 200mm. In some embodiments, a first layer is laid, for example, with a depth of about 150mm at 220, and then compacted, at 230. A second layer is then laid at 240 on the first layer and compacted at 250. For example, the second layer may be of a similar thickness to the first layer. A third layer, which may be of a similar thickness to the first and/or second layer, may then be laid and compacted, and so on until the cavity is filled, at 260.

Compaction may occur by manually tamping each layer after it has been placed in the cavity, by using a powered equipment, or by a combination of both manual tamping and powered equipment. An example of suitable powered equipment is a non-rotating standard hammer-drill with specialised 20mm solid steel feet attachments.

The rammed earth portion 110 is left to dry in the mould until set at 270. In some embodiments, the rammed earth portion 110 is left to dry for a minimum of 12 hours. Once set, the rammed earth portion 110 is substantially non-plastic, or has at least relatively low plasticity. This may mean that it has a solid consistency with little to no moisture contained. This results in a material with relatively low compressibility. When installed as part of the panel 100, the rammed earth portion110 resembles conventional rammed earth walls, albeit with reduced weight and volume.

Part of the mould is then removed to expose the second face of the rammed earth portion 110 and left to completely dry, as at 280. Herein, the first face of the rammed earth portion 110 is the facadee" side of the panel 100. In other words, the first face is the main visible face of the panel 100 after it is installed on a structure such as a wall frame to form a facade of the structure. In some embodiments, the first face is kept in the mould to protect it until the panel 100 is completed, and the face exposed by the removal of part of the mould is the second face.

When the second face is completely dry, a sealant is applied to it to seal the second face of the rammed earth portion and provide for improved coupling to a face of the supporting portion 160, at 290. The sealant may also provide the rammed earth portion 110 with a water-repellent or waterproof coating. Applying the sealant may strengthen the second face of the rammed earth portion 110 so that the supporting portion 160 can be coupled to the rammed earth portion 110 without loose particles compromising the strength of the connection. An example of a suitable sealant is an acrylic-based sealer such as "Earth Binder" by Tech-Dry Building Products. In some embodiments, sealant is also applied to the supporting portion 160, at 300, prior to coupling with the rammed earth portion 110. The sealed second face of the rammed earth portion is then coupled to the third face, and in some embodiments, the sealed third face, of the supporting portion 160, at 310.

The coupling means used to couple the rammed earth portion 110 and the supporting portion 160 may be an adhesive, mechanical fasteners, or a combination thereof. Preferably, an adhesive is used to avoid eating into the rammed earth portion 110 with a mechanical fastener such as a screw or bolt, particularly if the first thickness is quite thin. A suitable adhesive is Sikaflex-11FC, which is a polyurethane-based adhesive suitable for indoor and outdoor applications. Once is adhesive is applied and the rammed earth portion 110 and the supporting portion 160 are coupled, the two portions may be clamped together to ensure a firm adhesive bond. In this clamping arrangement, the first face of the rammed earth portion may still be covered by the formwork to protect it from damage by the clamps. By sealing the second face of the rammed earth portion 110, and in some embodiments, the third face of the supporting portion 160, a suitable surface for accommodating the adhesive is formed, which allows the adhesive to be more uniformly applied and to improve the coupling of the rammed earth portion 110 to the supporting portion 160.

After the coupling has been performed, for example, the adhesive has set, the clamps are released and the mould/formwork is carefully removed to reveal the complete panel

100, at 320, as shown in Figure 3. The remaining (unsealed) surfaces of the panel 100 may be coated with the sealant to provide the panel 100 with water-resistance. For example, in embodiments of the method 200 where the second and third faces were sealed before coupling, the other faces of the rammed earth portion 110 and the supporting portion 160 were unsealed. After the sealant has dried, the completed panel 100 can be packed into crates for transport.

The ability to manufacture the rammed earth panels 100 off-site provides advantages over the manufacturing process for conventional rammed earth walls, which are built in-situ. Advantages may include having a controlled environment where adverse weather conditions are less likely to affect manufacture of the rammed earth, and time, cost, and efficiency benefits from the potential economies of scale as the panels 100 may be produced at a specialist factory on a production line. Faster installation than conventional rammed earth walls, which are made and assembled on site. No site time needed to wait for it to dry.

The supporting portion 160 may be a board, sheet, frame, or other rigid structure to provide support to the rammed earth portion 110 and to allow the completed panel 100 to be mounted to a structure by coupling means, without the coupling means contacting the rammed earth portion 110. The supporting portion 160 may or may not be the same size as the rammed earth portion 110. For example, the supporting portion 160 may be bigger so that its perimeter extends beyond that of the rammed earth portion 110. Alternatively, the perimeter of the supporting portion 160 may not extend beyond that of the rammed earth portion 110.

The second thickness, geometry, and material of the supporting portion 160 is chosen to contribute sufficient stiffness to the panel 100 without making the panel 100 too heavy or unwieldy for workers to install on site without using lifting equipment. In some embodiments, the supporting portion 160 is a plywood board and the second thickness is 18mm. Applying the sealant to the plywood board reduces the likelihood and/or extent of moisture being absorbed by the plywood and causing delamination of the plywood's layers, or rotting.

The first length 115, second length 120, and first thickness 135 may be selected so that the rammed earth portion 110 has aspect ratios which reduce the likelihood and extent of cracking in the mixture as it dries and shrinks. The first and second lengths 115, 120 may be approximately between 200mm and 2000mm, and first thickness 135 may be approximately between 10mm and 200mm. In some embodiments of the rammed earth portion 110, the first length 115 is approximately 1350mm, the second length 120 is approximately 600mm, and the first thickness 135 is approximately 25mm, providing the rammed earth portion 110 with suitable aspect ratios to reduce the likelihood and extent of cracking as the mixture dries and shrinks. An overall thickness of the panel 100 may be the sum of the first and second thicknesses 135, 175, not including the thickness of any added coatings such as the sealant or adhesive.

Embodiments of the panel 100 may be manufactured in separate panels sized so that each of the individual panels 100 is able to be carried and installed onto structure by hand to minimise the need for lifting equipment such as a crane or forklift. For example, a panel 100 having a rectangular configuration measuring approximately 1350mm by 600mm by 45mm has an approximate weight of 48kg. This size and weight of panel means that the panel is able to be carried and positioned on site by 2 or 3 workers, for example.

Advantageously, embodiments of the panel 100 having such sizes and weights are able to be installed on existing structure without the need for significant reinforcement of the structure itself or its foundations, as would be needed to support the weight of a conventional rammed earth wall.

In some embodiments, the panel 100 has a shape substantially comprising a polygon, such as a rectangle, triangle, pentagon, or hexagon. Some embodiments of the panel 100 comprise a polygon, or a curved shape, or combinations thereof. Preferably, the shape of the panel 100 allows for tessellation of a plurality of the panel 100.

A plurality of panels 100 can be assembled on site to cover a larger surface area of structure 400, as shown in Figure 4. This allows individual panels to have a size and weight that is manoeuvrable without lifting equipment, while being capable of being placed in a tessellating pattern to a clad a large surface area with minimal gaps between panels.

The panel 100 may be attached to structure such as a timber stud wall frame 410, as shown in Figure 5. Screws, nails, or similar mechanical fasteners may be used in conjunction with a bracket or angled section 500 to rigidly the panel 100 to the timber stud. Figure 5 also shows an adjoining panel 100. The gap between the panels 100 may be filled with a colour-matched acrylic gap filler 550.

Instead of mechanical fasteners, adhesives may be used to attach the panel 100 to the structure. Figure 6 shows the panel 100 attached to a timber stud 410 by an adhesive layer 600. Figure 7 shows the panel 100 attached to a concrete or blockwork wall 700 by a similar adhesive layer.

In some embodiments, the first face is parallel to the second face. In some embodiments, the second face is not parallel to the first face. All or part of the first face may have an undulating or textured surface for aesthetic purposes. All or part of the second face may be smooth to facilitate attachment to the structure. In some embodiments, the panel 100 may be curved so that the panel 100 may clad all or part of a curved structure such as a rounded pillar. This may, for example, comprise at least one of the first, second, third, or fourth faces not being flat.

Possible applications for embodiments of the panel 100 include use as cladding for new and existing walls in higher-rise structures, and for interior walls. In some embodiments, the panel 100 may be used for external walls. In some embodiments, the panel 100 may be used for parts of external walls which are sheltered from the elements. For example, during renovation of a space in a high-rise office tower, the existing timber stud wall and/or plasterboard may be substantially retained, and an embodiment of the panel 100 installed on the existing wall to provide a facade for an interior part of the structure. The use of rammed earth for interior walls may improve the thermal and/or acoustic performance of the wall in question, and may also provide an aesthetic effect that is similar to conventional rammed earth walls that are built in situ.

Compared to conventional rammed earth walls, embodiments of the panel 100 have a wider range of possible applications. Embodiments of the panel 100 may also provide a useful alternative to known cladding panels.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A cladding panel, comprising: a rammed earth portion having a first face, and a second face, the second face disposed opposite the first face to define a first thickness of the rammed earth portion; a sealant applied to the second face of the rammed earth portion; a supporting portion having a third face and a fourth face, the third face disposed opposite the fourth face to define a second thickness of the supporting portion; and wherein the third face of the supporting portion is coupled to the second face of the rammed earth portion, the fourth face of the supporting portion is configured to be connected to a structure to be clad, and the first face of the rammed earth portion forms an exposed surface of the cladding panel; and wherein the rammed earth portion exhibits relatively low linear shrinkage.

2. The panel of claim 1, wherein the rammed earth portion exhibits relatively low plasticity or is non-plastic.

3. The panel of claim 1 or claim 2, wherein the rammed earth portion comprises a mixture of an aggregate, a sand, water, and a cement binder.

4. The panel of claim 3, wherein the aggregate comprises minus crushed rock.

5. The panel of any one of claims 1 to 4, wherein sealant is applied to one or more of: the first face of the rammed earth portion, the third face of the supporting portion and the fourth face of the supporting portion.

6. The panel of any one of claims 1 to 5, wherein the rammed earth portion comprises less than 80% aggregate and about 8% water.

7. The panel of any one of claims 1 to 6, wherein the supporting portion comprises a plywood board.

8. The panel of any one of claims 1 to 7, wherein the first thickness is approximately 25mm, and wherein the second thickness is approximately 18mm.

9. A cladded structure comprising a plurality of the panels of any of the preceding claims, wherein the first faces of the plurality of panels collective form a facade of the cladded structure.

10. A method for manufacturing a cladding panel, the method comprising: forming a rammed earth portion of the cladding panel in a mould, the rammed earth portion having a first face, and a second face, the second face disposed opposite the first face to define a first thickness of the rammed earth portion, wherein the rammed earth portion exhibits relatively low linear shrinkage; releasing part of the mould to expose the second face of the rammed earth portion; applying sealant to the second face; providing a supporting portion having a third face and a fourth face, the third face disposed opposite the fourth face to define a second thickness of the supporting portion; coupling the third face of the supporting portion to the second face of the rammed earth portion to form the cladding panel; and releasing the cladding panel from the mould.

11. The method of claim 10, wherein the method further comprises, after releasing part of the mould to expose the second face of the rammed earth portion and before applying the sealant, allowing the rammed earth portion to dry.

12. The method of claim 10 or claim 12, wherein forming the rammed earth portion comprises: preparing the mould, the mould having a body defining a cavity having a depth and a width, corresponding respectively to a length and thickness of the rammed earth portion; blending an aggregate, water, and a cement binder to form a mixture; placing and compacting consecutive layers of the mixture in the cavity to a first density until the cavity is filled; and drying the mixture in the mould;

13. The method of claim 12, wherein the mixture further comprises a water repellent or waterproof admixture.

14. The method of any one of claims 10 to 13, wherein the first depth is at least approximately 100mm.

15. The method of claim 14, wherein the first depth is approximately 150mm.

16. A cladding panel produced by the method of any one of claims 10 to 15.