Fiber cement board and wall structure with fiber cement board

Abstract

The fiber cement board includes a rectangular body having spaced apart upper and lower edges that are substantially parallel to one another, spaced apart first and second side edges that are substantially perpendicular to the upper and lower edges, and an inwardly facing surface and an outwardly facing surface. The first and second side edges are substantially parallel to one another and connect the upper and lower edges. The lower edge is further provided with a longitudinal groove and the upper edge is provided with a ridge adapted to be inserted into the groove of the lower edge of an adjacent identical fiber cement board. The first side edge is further provided with a groove and the second side edge is provided with a ridge adapted to be inserted into the groove of the first side edge of an adjacent identical fiber cement board.

Description

[Technical field]

[0001] The present disclosure relates generally to fiber cement boards for use in wall construction. Additionally, the present disclosure relates to wall constructions formed by assembling fiber cement boards having cooperating ridges and grooves disposed along adjacent edges. Such cement boards are often referred to as having "tongue and groove" connections. [Background technology]

[0002] When building a wall structure using fiber cement boards, it is common to create a back structure with vertical wooden beams and horizontal wooden cross beams connecting the vertical wooden beams. The fiber cement boards are then attached to the underlying wooden structure. The fiber cement boards are positioned such that all edges, both vertical and horizontal, of each fiber cement board are supported by the vertical and horizontal wooden beams via screws along the edges of the cement board. In this way, the adjacent edges between two adjacent fiber cement boards are supported by the wooden beams positioned behind the cement boards. The wooden beams are needed to support the edges of the cement boards to give strength to the wall. Furthermore, over time, the two adjacent edges may pull apart slightly due to dimensional changes in the material, forming a gap between the two adjacent edges. To ensure fireproofing, the wooden beams behind the cement boards ensure that this gap is covered. If the gap is open, flames may pass through the gap into the wall structure. In some cases, in the prior art, it is possible to use a galvanized steel H-beam to seal and support the edges of two adjacent cement boards, instead of a back wooden beam placed between the horizontal edges of the adjacent cement boards. Other forms of configurations for supporting / sealing the edges of adjacent cement boards are also known in the art.

[0003] However, known prior art types of wall structures are difficult to manufacture because they require both vertical wood beams and horizontal wood or steel beams. Furthermore, they require screws to attach the cement board to the underlying support structure, which makes installation time consuming and requires many screws. Also, the vertical and horizontal beams must be precisely positioned to provide adequate support for the edges of the fiber cement board.

[0004] Furthermore, in the prior art, fiber cement boards are large, i.e., they are heavy and generally too large to be safely carried by one worker. In many cases, the cement boards are so heavy that even two workers should not carry them by themselves, but rather require the use of mechanical lifting equipment. However, depending on the conditions at the work site, workers may be forced to carry a single cement board by themselves. This places physical stress on the workers, causing long-term fatigue that may result in sick leave.

[0005] Additionally, it is often desirable to make the wall structure wind and water proof, which is currently done by additionally applying waterproof tape to the joints between all adjacent cement boards on the exterior facing or weather exposed sides after all cement boards have been attached to the back beams.

[0006] It should also be noted that in some cases, such wall structures are assembled on a building as the final exterior wall structure. In other cases, such wall structures are first assembled as the exterior wall structure, but are later covered by a more permanent wall structure. For example, the fiber cement wall structure is assembled first, and then a brick exterior is installed to cover the fiber cement wall structure. However, depending on the construction process, many months may pass between the installation of the fiber cement wall structure and the covering of the fiber cement wall structure by the more permanent wall structure. In the period prior to the installation of the final exterior wall structure, the fiber cement wall structure must be windproof and waterproof.

[0007] It should also be noted that different forms of fiber cement boards are known in the art, having different forms of cooperating ridges and grooves that engage with each other. Such cement boards are often used for floors and / or interior walls where the requirements for strength, fire resistance and / or moisture / weather resistance are low. An example of such a cement board is disclosed in US2020157812. The shape of the ridges and grooves in this prior art type of cement board is not suitable for applications where there are cooperating ridges and grooves along all four sides of the cement board. This type of prior art cement board is more appropriately designed to mechanically lock two cement boards together, and requires the cement board to pivot about a vertical axis to engage with another cement board. This form is only suitable when only one edge is locked at a time. Summary of the Invention

[0008] A first aspect of the present invention is to provide a fiber cement board for wall construction having ridges and grooves along the edges of the cement board to facilitate assembly of the fiber cement board without the need for multiple horizontally and / or vertically oriented beams located behind each joint between two adjacent fiber cement boards.

[0009] A second aspect of the present invention is to provide a wall structure having a plurality of fiber cement boards engaged with one another via ridges and grooves, thereby eliminating the need for horizontally oriented beams to support the fiber cement boards.

[0010] A third aspect of the present invention is to provide a fiber cement board that does not require waterproofing tape to prevent water from entering a wall structure through the joint between two adjacent cement boards.

[0011] These aspects are at least partially realized by the fiber cement board according to claim 1. According to claim 1, the fiber cement board includes a rectangular body having spaced apart upper and lower edges that are substantially parallel to each other, spaced apart first and second side edges that are substantially perpendicular to the upper and lower edges, and an inwardly facing surface and an outwardly facing surface. The first and second side edges are substantially parallel to each other and connect the upper and lower edges. The lower edge is further provided with a groove and the upper edge is provided with a ridge adapted to be inserted into the groove of the lower edge of an adjacent identical fiber cement board. The first side edge is further provided with a groove and the second side edge is provided with a ridge adapted to be inserted into the groove of the side edge of an adjacent identical fiber cement board. A sealant is further provided in the groove of the first side edge.

[0012] It should be noted that the term "ridge" should be understood as a protrusion that extends in an elongated manner along the edge of the cement board, and similarly, the term "groove" should be understood as a groove that extends along the edge of the cement board.

[0013] It should also be noted that although the cement board is not part of the wall structure, the inward and outward facing surfaces may be interpreted as first and second surfaces since the terms inside and outside are the orientations that the cement board initially defines when it becomes part of the wall structure.

[0014] Also, as mentioned above, when the cement board is not part of the wall structure, the top edge and bottom edge can be considered as the first edge and second edge. The terms "top" and "bottom" are the first practical definitions when the cement board becomes part of the wall structure. However, the terms "top edge" and "bottom edge" are terms that make the claims more clear to those skilled in the art.

[0015] In one embodiment, the sealant is only provided in the first side edge groove, with the bottom edge groove having no sealant.

[0016] In one embodiment, the sealant includes a release strip that is removed prior to installation of the fiber cement board.

[0017] In one embodiment, the sealant is in the form of a paste, is essentially non-hardening during the life of the sealant, and retains adhesion and elasticity during the life of the sealant.

[0018] In some embodiments, the sealant is disposed at the base or bottom of the groove. In some embodiments, the grooves of the first side edge, the ridges of the second side edge, and the placement of the sealant within the grooves are disposed such that when the ridges of the second side edge of one cement board are inserted into the grooves of the first side edge of an adjacent cement board, the tips of the ridges engage the sealant. In some embodiments, the tips of the ridges engage the sealant such that the sealant wraps around the tips of the ridges. In some embodiments, after the tips of the ridges engage the sealant, the sealant is disposed on both the outward facing side and the inward facing side of the ridges.

[0019] In some embodiments, the sealant is disposed closer to the outwardly facing surface of the cement board than to the inwardly facing surface of the cement board. In some embodiments, at least a portion of the sealant is disposed at a location within the groove strip between the base of the groove and the outwardly facing surface of the cement board. In this way, water ingress into the vertical groove is stopped before it reaches the base of the groove. In some embodiments, at least a portion of the sealant is disposed at a location within the groove strip between a plane connecting the base of the groove strip along the bottom edge of the cement board to the tip of the ridge at the top edge of the cement board and the outwardly facing surface of the cement board. In this way, water ingress into the vertical groove is stopped at a location outside the tip of the ridge at the top edge of the adjacent cement board when the cement board is assembled into a wall structure, thereby ensuring that water ingress into the vertical groove does not exceed the tip of the ridge at the top edge of the adjacent cement board.

[0020] In some embodiments, the grooves on the first side edge and the ridges on the second side edge are positioned such that movement along a direction parallel to the plane of the first cement plate and the second cement plate can insert the ridges on the second side edge of the first cement plate into the grooves on the first side edge of the second cement plate adjacent to the first cement plate.

[0021] In some embodiments, the ridges on the top edge and the ridges on the second side edge are the same, in some embodiments, the grooves on the bottom edge and the grooves on the first side edge are the same.

[0022] In one embodiment, the exterior surface is provided with a hydrophobic coating that reduces water infiltration thereto. In this way, the cement board may be prevented from deforming over time when the exterior surface is exposed to moisture. When one side of the fiber cement board becomes wetter than the other, the cement board may also flex toward the wetter side. This is not an issue with regular cement boards, since the cement board is usually secured to the underlying frame structure using a number of screws. Unlike current systems, certain configurations of grooves and protrusions should reduce flexure. Depending on the shape and configuration of the protrusions and grooves, extensive flexure of the cement board may cause the protrusions and / or grooves to break, thereby reducing the strength of the joint between adjacent cement boards and / or reducing the waterproofing of the wall structure provided by the cement board.

[0023] In one embodiment, the hydrophobic coating is applied by roller, spray, dipping, or another suitable method. In one embodiment, the hydrophobic coating comprises any one of a silane, a siloxane, a silicone resin, a metal stearate, a hydrophobic polymer, or a combination thereof. The specific amount of hydrophobic coating applied depends on the properties of the actual cement board used. This amount should be sufficient to prevent unacceptable deflection of the cement board when exposed to moisture. However, in some cases, the cement board needs to retain a certain permeability to water vapor, i.e., the cement board needs to remain "breathable". Those skilled in the art of fiber cement boards can provide the appropriate amount of the appropriate coating to provide the desired properties and provide the appropriate tradeoff between breathability and waterproofing.

[0024] In one embodiment, the fiber cement board is part of a wall structure, with the side edge grooves and ridges oriented vertically and the outward facing surface positioned further from the center of the wall structure than the inward facing surface. In some embodiments, the wall structure is positioned as an exterior wall structure. In some embodiments, the outward facing surface of the fiber cement board is positioned as the surface exposed to weather.

[0025] In one embodiment, the fiber cement board has a thickness of 9 mm and includes an outwardly facing face having a length of 1500 mm and a width of 600 mm. In one embodiment, the fiber cement board has ridges that extend 1 cm beyond the face edge, so that the overall length of the board is 1510 mm and the overall width is 610 mm. Other dimensions are possible, as described later in this specification.

[0026] In one embodiment, one or more dimensions of the fiber cement board may change due to changes in ambient temperature and humidity, and the sealant is adapted to expand and / or compress to maintain a seal between the two connected fiber cement boards. In one embodiment, the sealant has adhesive properties such that the adhesive forms an adhesive connection between the ridges and grooves of the two adjacent cement boards. In one embodiment, the adhesive properties of the sealant have high elasticity and high elongation at break. In this way, the sealant remains attached to the cement board but easily stretches as the dimensions of the cement board change. In this way, the sealant does not contribute significantly to holding the cement boards together. This is in contrast to more traditional adhesives that are intended for bond strength to bond adjacent cement boards together. In one embodiment, the elongation at break is greater than 100%, greater than 200%, or greater than 300%. In one embodiment, the strength of the adhesive is low. In one embodiment, the strength modulus of the adhesive is less than 1 MPa, less than 0.5 MPa, or less than 0.25 MPa.

[0027] In one embodiment, the length of the fiber cement board may decrease by 2mm to 4mm due to ambient temperature and humidity, and the sealant is adapted to stretch to maintain a sealing contact between adjacent cement boards.

[0028] According to an additional aspect of the present invention, a wall structure is disclosed that includes an array of vertically or horizontally extending support beams and a plurality of fiber cement planks attached to the beams and engaged with one another, each fiber cement plank having first and second vertically oriented side edges, first and second horizontally oriented edges, and an inwardly facing surface and an outwardly facing surface.

[0029] In some embodiments, the wall structure is an exterior wall structure. In some embodiments, an exterior facing surface of the plurality of fiber cement boards is positioned as a surface exposed to weather.

[0030] The first horizontally oriented edge has a longitudinal groove and the second horizontally oriented edge has a ridge that is disposed inside the groove of the first horizontally oriented edge of an adjacent identical fiber cement board. Additionally, the first vertically oriented edge has a groove and the second vertically oriented edge has a ridge that is disposed inside the groove of the first vertically oriented edge of an adjacent fiber cement board, and the sealant is disposed within the groove of the first vertically oriented edge. In some embodiments, the sealant is disposed at the base or bottom of the groove of the first vertically oriented edge. In some embodiments, the sealant wraps around the tip of the ridge of the second vertically oriented edge that is disposed inside the groove of the first vertically oriented edge of the adjacent fiber cement board.

[0031] In some embodiments, at least a portion of the sealant is disposed closer to the outwardly facing surface of the cement board than to the inwardly facing surface of the cement board. In some embodiments, at least a portion of the sealant is disposed at a location within the groove stripe between the base of the groove and the outwardly facing surface of the cement board. In this way, water ingress into the vertical groove is stopped before it reaches the base of the groove. In some embodiments, at least a portion of the sealant is disposed at a location within the groove stripe between a plane connecting the base of the groove stripe along the bottom edge of the cement board to the tip of the ridge at the top edge of the cement board and the outwardly facing surface of the cement board. In this way, water ingress into the vertical groove is stopped at a location outside the tip of the ridge at the top edge of the adjacent cement board, thereby ensuring that water ingress into the vertical groove does not exceed the tip of the ridge at the top edge of the adjacent cement board.

[0032] In one embodiment, the first horizontally oriented edge is a bottom edge of the fiber cement plank and the second horizontal edge is a top edge of the fiber cement plank.

[0033] In one embodiment, the grooves on the first horizontally disposed edge of each fiber cement plank do not have a sealant.

[0034] In one embodiment, the outward facing surface of each fiber cement plank is provided with a hydrophobic coating that reduces the ingress of water to that surface.

[0035] In one embodiment, the plurality of fiber cement boards are arranged in a horizontally oriented staggered arrangement, hi one embodiment, the vertically disposed edges of the lower cement boards are horizontally offset from the vertically disposed edges of the upper cement boards.

[0036] In one embodiment, the sealant includes a release strip that is removed prior to attaching the fiber cement board to the joist.

[0037] In one embodiment, the sealant is in the form of a paste, is non-hardening during the life of the sealant, and retains adhesion and elasticity during the life of the sealant.

[0038] In one embodiment, one or more dimensions of the fiber cement plank change due to changes in ambient temperature and humidity, and the sealant is adapted to expand and / or compress in order to maintain a seal between the two connected fiber cement planks.

[0039] In one embodiment, the length of the fiber cement board may decrease by at least 2 mm, at least 3 mm, or at least 4 mm due to ambient temperature and humidity, and the sealant is adapted to stretch to maintain a sealing contact between adjacent cement boards.

[0040] According to yet another aspect, a method of forming a wall structure is provided that includes providing an array of vertically or horizontally extending support beams and providing a plurality of fiber cement planks, each of which includes a top edge with a ridge, a bottom edge with a groove, a first vertically oriented edge with a groove, a second vertically oriented edge with a ridge, and a sealant disposed inside the grooves of the first vertically oriented edge. The method further includes attaching a first fiber cement board of the plurality of fiber cement boards to at least one of the support beams; and engaging a second fiber cement board of the plurality of fiber cement boards with the first fiber cement board by aligning a bottom edge of the second fiber cement board with a bottom edge of the first fiber cement board and sliding the second fiber cement board horizontally to insert a ridge of the second vertically oriented edge of the first fiber cement board or a ridge of the second vertically oriented edge of the second fiber cement board into a groove of the first vertically oriented edge of the second fiber cement board or a groove of the first vertically oriented edge of the first fiber cement board so that the sealant is crushed.

[0041] In one embodiment, the method further includes engaging a third fiber cement board of the plurality of fiber cement boards with a first fiber cement board by sliding the third fiber cement board vertically downward and engaging a ridge on an upper edge of the first fiber cement board with a groove on a lower edge of the third fiber cement board.

[0042] In one embodiment, the method further includes engaging a fourth fiber cement board of the plurality of fiber cement boards with the first and / or second fiber cement board by sliding a fourth fiber cement board vertically downward to fit a ridge on a top edge of the first and / or second fiber cement board into a groove on a bottom edge of the fourth fiber cement board, and then sliding the fourth fiber cement board horizontally toward a third fiber cement board to insert a ridge on a second vertically oriented edge of the fourth fiber cement board or a ridge on a second vertically oriented edge of the third fiber cement board into a groove on a first vertically oriented edge of the third fiber cement board or a groove on a first vertically oriented edge of the fourth fiber cement board to crush the sealant.

[0043] In one embodiment, the fiber cement boards are attached to the beams in a horizontally oriented staggered arrangement. In one embodiment, the fiber cement boards are positioned such that the vertically oriented edge of an upper cement board is horizontally offset from the vertically oriented edge of an adjacent cement board below.

[0044] In the following, the invention will be described in more detail with reference to the embodiments shown in the attached drawings, in which it is emphasized that the illustrated embodiments are used for illustrative purposes only and should not be used to limit the scope of the invention. [Brief description of the drawings]

[0045] [Figure 1] FIG. 1 is a front view of a wall structure having an array of vertically extending beams and a number of fiber cement boards attached to the beams. [Diagram 2] FIG. 2 is a cross-sectional view of the wall structure taken along the section line II-II. [Diagram 3] FIG. 3 is a cross-sectional view of the wall structure taken along the section line III-III. [Figure 4] FIG. 4 is an enlarged view of a portion of the cross-section shown in FIG. 3, illustrating a side ridge of a fiber cement board positioned inside a side groove of an adjacent fiber cement board. [Diagram 5]3 is an enlarged view of a portion of the cross-section of the wall structure shown in FIG. 2, showing the longitudinal ridges of a fiber cement board positioned inside the longitudinal grooves of an adjacent fiber cement board. [Figure 6] FIG. 5 shows the side grooves and longitudinal ridges of FIG. 4 spaced apart from one another prior to assembly, with sealant disposed inside the side grooves. [Figure 7] 6 shows the longitudinal grooves and longitudinal ridges of FIG. 5 spaced apart prior to assembly. [Figure 8] FIG. 2 is an enlarged view of a first embodiment of a groove in one fiber cement board and a ridge in another fiber cement board, showing a sealant placed on the inside of the groove prior to assembling the two fiber cement boards. [Figure 9] FIG. 9 is a close-up view of the embodiment of FIG. 8 showing two fiber cement boards assembled together. [Figure 10] FIG. 2 is a close-up view of a second embodiment of grooves in one fiber cement plank and ridges in another fiber cement plank showing sealant disposed inside the grooves. [Figure 11] FIG. 11 is an enlarged view of the embodiment of FIG. 10 showing two fiber cement boards assembled together. [Figure 12] 1A-1D illustrate various stages of assembling fiber cement boards with support beams to form a wall structure. [Figure 13] 1A-1D illustrate various stages of assembling fiber cement boards with support beams to form a wall structure. [Figure 14] 1A-1D illustrate various stages of assembling fiber cement boards with support beams to form a wall structure. [Figure 15] 1A-1D illustrate various stages of assembling fiber cement boards with support beams to form a wall structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Referring to FIG. 1, a wall structure 100 according to one embodiment of the present disclosure is shown. The wall structure 100 includes a plurality of vertically extending support beams 102 and a plurality of fiber cement boards 104 attached to the beams 102 and engaged with each other. As shown, the beams 102 are arranged horizontally and spaced apart from each other. In this embodiment, the lower ends 106 of the beams 102 are supported on and abut a surface (e.g., the ground). In this embodiment, the distance between any two adjacent beams 102 is equal. However, it will be understood that the distance between adjacent beams 102 may be different. Furthermore, although the beams 102 are shown and contemplated as wooden beams, it may be envisioned that the beams 102 may be made of any other suitable material, such as, but not limited to, steel, iron, and the like.

[0047] The fiber cement boards 104 are arranged in a number of horizontally extending rows 110. The rows 110 are arranged vertically along the length of the beam 102. As shown, the fiber cement boards 104 are arranged in a horizontally oriented staggered arrangement between the different rows 110. The construction of these fiber cement boards 104 is similar, so the structure and construction of a single fiber cement board 104 will be described.

[0048] 1 to 3, the fiber cement board 104 (hereinafter simply referred to as the cement board 104) has a front surface (or outward surface) 114, a back surface (or inward surface) 116 disposed opposite the front surface 114 and facing the beam 102, and four edges (i.e., a first longitudinal edge (or bottom edge) 120, a bottom edge (or bottom edge) 122 disposed at a distance from the first longitudinal edge 120, and a bottom edge (or bottom edge) 123 disposed at a distance from the first longitudinal edge 120). 1 includes a rectangular body 112 having a second longitudinal edge (or top edge) 122 disposed substantially parallel to axial direction 120, a first side edge 124 connecting the first longitudinal edge 120 and the second longitudinal edge 122, and a second side edge 126 disposed spaced apart from the first side edge 124 and disposed substantially parallel to the first side edge 124 and connecting the first longitudinal edge and the second longitudinal edge. As shown, the first side edge 124 and the second side edge 126 extend substantially perpendicular to the first longitudinal edge 120 and the second longitudinal edge 122. In assembly of the cement board 104 and the beam 102, the first longitudinal edge 120 and the second longitudinal edge 122 extend horizontally and substantially parallel to the ground, while the first side edge 124 and the second side edge 126 extend vertically. As shown, the first longitudinal edge 120 of the cement board 104 defines a bottom edge of the cement board 104, and the second longitudinal edge 122 of the cement board 104 defines a top edge of the cement board 104.

[0049] 2-7, the upper edge 122 includes a ridge 130 (shown in most detail in FIGS. 5 and 7) that extends outwardly from the body 112 and extends from the first side edge 124 to the second side edge 126, and the lower edge 120 includes a groove 132 (shown in most detail in FIGS. 5 and 7) that extends inwardly of the body 112. The groove 132 further extends from the first side edge 124 to the second side edge 126. In this embodiment, the ridge 130 is a tongue-like portion having a narrow top portion 134 and a wider bottom portion 136. Similarly, the groove includes a narrow base portion 138 for receiving the narrow top portion 134 of the ridge 130 of the adjacent cement board 104 and a wider top portion 139 for receiving the wider bottom portion 136 of the ridge 130 of the adjacent cement board 104. The particular dimensions and design of the tongue and groove embodiment shown in Figures 2-7 are shown only diagrammatically, whereas the design and dimensions of the tongue and groove embodiment shown in Figures 8-11 are more realistic.

[0050] Similarly, the first side edge 124 includes a groove 140 (shown in most detail in FIGS. 4, 6, 8, 9, 10, and 11) that extends inwardly of the body 112 toward the second side edge 126, and the second side edge 126 includes a ridge 142 (shown in most detail in FIGS. 4, 6, 8, 9, 10, and 11) that extends outwardly of the body 112 in a direction away from the first side edge 124. Both the side edge groove 140 and the ridge 142 extend along a vertical direction when assembled or attached to the beam 102. Additionally, the side edge groove 140 and the ridge 142 extend from the first longitudinal edge 120 to the second longitudinal edge 122. Similar to the longitudinal edge grooves 132, the side edge grooves 140 include a narrow inner portion 144 and a wider outer portion 146. Similarly, the side edge ridges 142 include a narrow outer portion 148 adapted to be inserted inside the narrow inner portion 144 of the side edge grooves 140 of an adjacent cement board 104 in the same row, and a wider inner portion 150 adapted to be placed inside the wider inner portion 146 of the side edge grooves 140 of an adjacent cement board 104. It should be noted that "inner" and "outer" are relative to the center of the cement board, with the inner being closer to the center of the cement board and farther from the center of the outer cement board.

[0051] Additionally, the fiber cement board 104 includes a sealant 160 (shown in most detail in FIGS. 6, 8, 9, 10 and 11) disposed at the base of the side edge grooves 140. The sealant 160 is adapted to prevent the passage of water or wind from the exterior into the interior of the wall structure 100 through the vertical joints defined between the side edge grooves 140 and the ridges 142 of adjacently disposed cement boards 104. In one embodiment, the sealant 160 retains some of its elasticity and adhesive properties over time. Thus, the sealant 160 is applied to the side edge grooves 140 of the cement boards 104 at a factory before being transported to the building site. In one embodiment, the sealant 160 is in the form of a paste that is non-hardening throughout its life. Thus, the sealant 160 retains its elasticity and adhesive properties. In some embodiments, the sealant 160 is of the type that is activated when crushed. Thus, any dust present during shipping and storage will not adhere to the sealant 160, and the sealant 160 will only become adhesive when subjected to a squeezing action during assembly.

[0052] In some embodiments, about 10% of the sealant 160 can be a combination of polyisobutylene and ethylene propylene diene monomer (EPDM) to ensure that the sealant 160 can remain uncured, tacky / adhesive, and highly elastic. The high elasticity of the sealant 160 allows the sealant 160 to compensate for movement (up to 2.4 mm / m) of the installed fiber cement board 104 caused by rain, heat, and other weather effects.

[0053] In another embodiment (not shown), a thin outer "skin" or film is formed on the exterior surface of the sealant 160 after the sealant 160 is applied to the grooves 140. However, the sealant 160 remains soft inside the film. The outer film of the sealant 160 repels dust and dirt during shipping and storage. When the ridges 142 are inserted into the grooves 140, the outer film breaks, releasing the soft sealant material. In this manner, the sealant 160 retains its elasticity and adhesive properties.

[0054] In another embodiment, a release strip (not shown) may be provided on the surface of the sealant 160. The release strip is removed at the construction site prior to installing or attaching the fiber cement board 104 to the joists 102. The release strip may keep the sealant 160 soft, elastic, and free of dust and dirt.

[0055] In the embodiment shown in Figures 1-7 and 12-15, the ridges 142 and grooves 140 fit perfectly together. However, in another embodiment shown in Figures 8 and 9, the height of the ridges 142 is less than the depth of the grooves 140. In this way, there is more room for the sealant 140 to spread into the grooves when the ridges are pressed into the sealant.

[0056] In another embodiment shown in Figures 10 and 11, the inner portion 150 of the ridge 142 may be positioned to fit snugly with the outer portion 146 of the groove 140, but the outer portion 148 of the ridge 142 may be narrower than the inner portion 144 of the groove 140. As a result, the narrow outer portion 148 of the ridge 142 can be forced into the sealant 160, while the inner portion 144 of the groove 140 has room to properly seal the ridge 142. It can be seen that the sealant wraps around the tip of the ridge to form an effective seal. In this case, a portion of the sealant is disposed on the inward facing surface of the ridge and a portion of the sealant is disposed on the outward facing surface of the ridge. At the same time, the outer portion of the groove and the inner portion of the ridge fit snugly together to provide a good edge fixation for the cement board.

[0057] Although the bottom edge groove 132 is shown without a sealant, it will be understood that a sealant similar to, or even identical to, sealant 160 may be disposed at the bottom of the bottom edge groove 132.

[0058] In this embodiment, a hydrophobic coating comprising a combination of silane, siloxane, and acrylic binder is applied via roller to the exterior surface of the cement board at the factory. The coating prevents the exterior surface of the cement board, i.e., the surface exposed to weather, from absorbing excess moisture. This reduces undesirable bowing of the cement board when it is exposed to moisture, such as when the wall structure is an exterior wall structure.

[0059] It should be noted that hydrophobic coatings may be necessary in some cases, but not in others. For example, for cement boards used in drier environments, hydrophobic coatings may be avoided. Similarly, depending on the shape and arrangement of the grooves and ridges of the cement board, the flexure of the cement board may be more or less relevant to the integrity of the wall structure that includes the cement board. For example, in certain groove / ridge designs, cement boards without hydrophobic coatings may flex so much when exposed to moisture that the grooves / ridges are damaged over time, affecting the structural strength and weather resistance of the wall covering. However, in other designs, the flexure of the cement board may have a less damaging effect on the grooves / ridges. In these cases, hydrophobic coatings may be avoided.

[0060] Next, an embodiment of a method for forming a wall structure 100 according to the present invention will be described. The method includes providing an array of vertically extending beams 102. The beams 102 are provided such that the beams 102 are arranged horizontally and spaced apart from one another. Each beam 102 extends vertically. The beams 102 are positioned such that a lower end 106 of the beam abuts a support surface. The method further includes providing a plurality of fiber cement boards 104, for example, a first fiber cement board 104a (shown in FIGS. 10-13), a second fiber cement board 104b (shown in FIGS. 11-13), a third fiber cement board 104c (shown in FIGS. 12 and 13), and a fourth fiber cement board 104d (shown in FIG. 13). The method includes attaching the first cement board 104a to at least one of the beams 102 via fasteners (e.g., screws). In one embodiment, as shown in Figure 10, the first cement plate 104a is attached such that the first cement plate 104a is located at the bottom left corner of the array of beams 102 and completely covers the width of the leftmost beam 102. The first cement plate 104a is also positioned or attached to at least one beam 102 such that the first longitudinal edge 120 is oriented horizontally and defines the bottom edge of the first cement plate 104a, and the second longitudinal edge 122 defines the top edge of the first cement plate 104a and is also oriented horizontally. Thus, the groove 132 is positioned adjacent the bottom end 106 of the beam 102 and faces the support surface, and the ridge 130 extends vertically upward.

[0061] Similarly, a first side edge 124 is vertically oriented and disposed substantially parallel to the beam 102 and defines a left edge of the first cement plate 104a, and a second side edge 126 defines a right edge of the first cement plate 104a that is also vertically oriented. Note that in this embodiment, the length of the longitudinal edges 120, 122 is greater than the length of the side edges 124, 126.

[0062] After the first cement plate 104a is installed, the second cement plate 104b is engaged with the first cement plate 104a and attached to one or more beams 102 using fasteners. To engage the second cement plate 104b with the first cement plate 104a, the first side edge 124 of the second cement plate 104b is placed facing and aligned with the second side edge 126 of the first cement plate 104a, as shown in FIG. 11. The second cement plate 104b is then slid toward the first cement plate 104a such that the ridges 142 of the second side edge of the first cement plate 104a are inserted into the grooves 140 of the first side edge of the second cement plate 104b. When the ridges 142 of the first cement board 104a are inserted into the grooves 140 of the second cement board 104b, the sealant 160 present in the grooves 140 of the second cement board 104b is pushed out (see FIG. 9), and the sealant 160 moves outward. At this time, the sealant 160 flows outward between the grooves 140 of the second cement board 104b and the ridges 142 of the first cement board 104a, so that the sealant 160 is disposed between the grooves 140 of the second cement board 104b and the ridges 142 of the first cement board 104a. This causes the vertical joints between the first cement board 104a and the second cement board 104b to be sealed by the sealant 160. In this manner, the various cement boards 104 are horizontally disposed in the first row 110.

[0063] It should be noted that in the figures, the side edge ridge is located on the right side of the cement board and the side edge groove is located on the left side of the cement board. However, the reverse arrangement may be made within the scope of the present invention. Similarly, construction begins in the lower left corner of the figure and cement boards are added from the right. However, a situation in which cement boards are started in the lower right corner and cement boards are added from the left is also possible.

[0064] It should further be noted that in the figures the cement boards are shown as rectangular boards with the horizontal edges longer than the vertical edges. However, within the scope of the present invention the cement boards may be arranged such that the vertical edges are longer than the horizontal edges. Similarly, square cement boards are also contemplated.

[0065] Next, the third cement plate 104c is arranged in the second row 110 and coupled to the first cement plate 104a. To do so, as shown in FIG. 12, the bottom edge 120 of the third cement plate 104c is aligned with the top edge 122 of the first cement plate 104a, and the third cement plate 104c is moved vertically downward. At this time, the ridges 130 of the first cement plate 104a are inserted into the grooves 132 of the third cement plate 104c, thereby connecting the third cement plate 104c to the first cement plate 104a. As shown, the third cement plate 104c is engaged with the first cement plate 104a such that the second side edge 126 of the third cement plate 104c is offset from the second side edge 126 of the first cement plate 104a. In this way, the side edges of the upper row are not aligned with the side edges of the lower row, which increases the strength of the wall structure.

[0066] Thereafter, as shown in FIG. 13, a fourth cement board 104d is attached to the third cement board 104c in a manner similar to the manner in which the second cement board 104b is attached to the first cement board 104a. The fourth cement board 104d is also engaged with the first cement board 104 and the second cement board 104b in a manner similar to the engagement of the third cement board 104c with the first cement board 104a. However, this process may be easier for the builder in that the fourth cement board can be placed on the first cement board / second cement board first such that the bottom edge of the fourth cement board engages with the top of the first cement board / second cement board. The fourth cement board can then be slid to the left so that the grooves on the side edges of the fourth cement board engage with the ridges on the side edges of the third cement board. In this way, the builder can easily place the cement board in place without having to hold it in a precise position. The builder can roughly set a cement board in place, then slide it horizontally to engage a third cement board, and then fasten a fourth cement board to the support beam.

[0067] The second cement board 104b, the third cement board 104c, and the fourth cement board 104d are also attached to the beam 102 using fasteners. In this manner, the various cement boards 104 are engaged with the beam 102 and adjacent cement boards 104 to form the wall structure 100. Because the cement boards 104 are engaged with one another by engaging the ridges 130, 142 with the respective grooves 132, 140, the need for horizontal beams to secure the cement boards 104 within the wall structure 100 is eliminated. The configuration of the ridges 130, 142 and grooves 132, 140 of the cement boards 104 also facilitates fastening the cement boards 104 to the beam 102 at any location, rather than aligning the edges 120, 122, 124, 126 with the beam 102 to connect the edges 120, 122, 124, 126 with the beam 102. Additionally, the horizontally oriented staggered arrangement of the cement boards 104 facilitates reducing the likelihood of water or wind infiltration through vertically oriented joints to the interior of the wall structure 100. Also, approximately one-third as many fasteners are used in attaching the fiber cement boards 104 to the joists 102 as compared to prior art types of wall structures, primarily because the edges 120, 122 of the fiber cement boards 104 do not need to be supported by back joists and fasteners along the edges.

[0068] It should be noted that the drawings and the above description are simple and schematic depictions of exemplary embodiments, and many of the specific mechanical details have not been shown, as those skilled in the art should be familiar with these details and would only unnecessarily complicate the above description.

Claims

1. 1. A fiber cement board for a wall construction comprising: a rectangular body having spaced apart upper and lower edges that are substantially parallel to one another, first and second spaced apart side edges that are substantially perpendicular to the upper and lower edges, and an inwardly facing surface and an outwardly facing surface, the first and second side edges being disposed substantially parallel to one another and connecting the upper edge and the lower edge, said lower edge being provided with a groove and said upper edge being provided with a ridge adapted to be inserted into a groove of an adjacent identical fiber cement board; the first side edge is provided with a groove and the second side edge is provided with a ridge adapted to be inserted into the groove of the first side edge of an adjacent identical fiber cement board; applying a sealant into the groove of the first side edge; A fiber cement board characterized by:

2. 2. The fiber cement board of claim 1, wherein the grooves on the bottom edge of the fiber cement board are free of sealant.

3. 3. A fibre cement board as claimed in claim 1 or claim 2, characterized in that the outwardly facing surface is provided with a hydrophobic coating which reduces the ingress of water to the outwardly facing surface.

4. 4. The fiber cement board of claim 1, wherein the fiber cement board is part of a wall structure, the grooves on the first side edge and the ridges on the second side edge are vertically oriented, and the outward facing surface is positioned further from a center of the wall structure than the inward facing surface.

5. A row of support beams extending vertically or horizontally; a plurality of fiber cement planks attached to the support beam and engaged with one another, each fiber cement plank having first and second vertically oriented edges, first and second horizontally oriented edges, and an inwardly facing surface and an outwardly facing surface; A wall structure comprising: the first horizontally oriented edge is a bottom edge having a groove thereon, and the second horizontally oriented edge is a top edge having a ridge disposed within the groove on the bottom edge of an adjacent fiber cement board; the first vertical edge is provided with a groove and the second vertical edge is provided with a ridge disposed inwardly of the groove of the first vertical edge of an adjacent fiber cement board; and applying a sealant within the grooves of the first vertically oriented edge; A wall structure comprising:

6. 6. The wall structure of claim 5, wherein the grooves on the first horizontally disposed edge of each fiber cement board are free of sealant.

7. 7. A wall structure as claimed in claim 5 or claim 6, characterised in that the outwardly facing surface of each fibre cement plate is provided with a hydrophobic coating which reduces the ingress of water to said outwardly facing surface.

8. A wall structure according to any one of claims 5 to 7, characterized in that the plurality of fibre cement boards are arranged in a horizontally oriented staggered arrangement.

9. 1. A method of forming a wall structure, comprising: providing an array of vertically or horizontally extending support beams; providing a plurality of fiber cement planks, each of the fiber cement planks including a top edge having a ridge, a bottom edge having a groove, a first vertically oriented edge having a groove, a second vertically oriented edge having a ridge, and a sealant disposed within the grooves of the first vertically oriented edge; attaching a first fiber cement board of the plurality of fiber cement boards to at least one of the support beams; and engaging a second fiber cement board of the plurality of fiber cement boards with the first fiber cement board by aligning a bottom edge of the second fiber cement board with a bottom edge of the first fiber cement board and sliding the second fiber cement board horizontally to insert a ridge of the second vertically oriented edge of the first fiber cement board or a ridge of the second vertically oriented edge of the second fiber cement board into a groove of the first vertically oriented edge of the second fiber cement board or a groove of the first vertically oriented edge of the first fiber cement board, respectively, to compress the sealant disposed within the groove of the second fiber cement board or the second vertically oriented edge of the first fiber cement board. The method includes:

10. 10. The method of claim 9, further comprising: engaging a third fiber cement board of the plurality of fiber cement boards with the first fiber cement board by sliding the third fiber cement board vertically downward and engaging a ridge on the top edge of the first fiber cement board with a groove on the bottom edge of the third fiber cement board.

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