AU2016100351A4

AU2016100351A4 - Prefabricated building module

Info

Publication number: AU2016100351A4
Application number: AU2016100351A
Authority: AU
Inventors: Patrick John Volpe
Original assignee: Volpe Patrick
Current assignee: Volpe Patrick
Priority date: 2016-04-01
Filing date: 2016-04-01
Publication date: 2016-05-12
Anticipated expiration: 2024-04-01

Abstract

Abstract: 2016100351 A prefabricated self-supporting building module, comprising a monolithic aerated concrete substrate and a cover layer, wherein the cover layer is fixed to an external surface of the substrate. By being prefabricated and having a cover layer, the building module of the present invention advantageously provides for surface-coated structural elements that can be directly assembled on site, thus reducing construction time. Also, by being prefabricated the building modules of the invention can be produced off-site in a controlled environment. This advantageously reduces weather related variables that typically adversely affect on site placement and coating of conventional AAC building elements. H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/0312016 - 1/4 a) b) c) d F u 10 Figure 1

Description

H:\anh\Interwoven\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 PREFABRICATED BUILDING MODULE FIELD OF THE INVENTION 5 The invention relates in general to building modules, and in particular to prefabricated building modules. BACKGROUND OF THE INVENTION 10 Conventional building construction techniques typically involve the initial assembly of a lightweight load bearing timber frame. Exterior wall claddings, internal linings, flooring, and roofing are subsequently attached to the frame to complete the building structure. Cladding, linings, flooring and ceiling systems are generally non-load bearing materials 15 and composite elements that provide thermal and acoustic insulation to the building. These may include wood, metal, plastic (e.g. vinyl), masonry or a range of composite materials such as closed cell or expanded polystyrene (EPS) foam-backed composites. A further layer of gypsum board or plasterboard is then generally applied to provide an exterior cover onto which a finish to walls and ceilings can be applied. 20 Inherent limitations of conventional building materials include poor fire-resistance and, particularly for composite and layered elements, extended construction times since they typically need to be assembled on site. 25 In recent years autoclaved aerated concrete (AAC) has been proposed as a lightweight alternative to conventional materials for cladding, flooring and ceiling structures. AAC is a type of lightweight concrete with entrapped air voids, which confers on it a lower density relative to conventional concrete. Due to its foam-like structure AAC may provide improved fire resistance and acoustic insulation. 30 However, AAC is mostly used in the form of non-load bearing elements (e.g. flat panels) in conjunction with supporting frames. As a result, if the load bearing portion of the H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 -2 building is timber frame, the structure would still be potentially exposed to the risk of fire damage. In addition, AAC elements are typically provided as bare concrete units with all concrete 5 surfaces exposed. As a result, after being assembled into a building structure (e.g. a wall, a floor, a ceiling) the exposed surfaces of the AAC elements need to be covered on site with a coating skin, such as plaster or wallboard coating, resulting in extended construction times. 10 An opportunity therefore remains to address or ameliorate disadvantages or shortcomings associated with traditional and current building materials and systems, to increase safety of buildings and minimise construction time. SUMMARY OF THE INVENTION 15 The present invention provides a prefabricated self-supporting building module comprising a monolithic aerated concrete substrate and a cover layer, wherein the cover layer is fixed to an external surface of the substrate. 20 By being prefabricated and having a cover layer, the building module of the present invention advantageously provides for surface-coated structural elements that can be directly assembled on site, thus reducing construction time. Also, by being prefabricated the building modules of the invention can be produced off-site in a controlled environment. This advantageously reduces weather related variables that typically adversely affect on 25 site placement and coating of conventional AAC building elements. In addition, depending on the shape of the substrate the building module of the present invention can be provided in an assortment of shapes suitable for the constructions of a variety of building structures. For example, the aerated concrete substrate may be provided 30 in the form of brick, panel, beam, column, lintel, L-block, or U-block. As a result, a H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -3 assortment of modules are available to be readily assembled into different building structures. This results in high structural efficiency and low wastage rates on site. The building modules of the invention may be inherently efficient acoustic and thermal 5 insulators since they comprise an aerated concrete substrate. This advantageously reduces the need for the on-site application of additional insulating layers. By being self-supporting, the building module of the invention is suitable for the construction of a building structure with no need for a supporting frame. Since supporting 10 frames are typically made of timber, by using the module of the invention it is possible to build structures that contain a substantially lower amount of flammable material compared to structures built according to conventional construction techniques. As a result, the module of the invention can provide for building structures with excellent fire resistance. 15 Another aspect of the invention provides for the use of a prefabricated self-supporting building module according to the invention in the construction of a building structure. In addition, the invention provides a method of making a prefabricated self-supporting building module, the module comprising an aerated concrete substrate and a cover layer, 20 and the method comprising fixing the cover layer to an external surface of the substrate. Further aspects and embodiments of the invention are described in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS 25 Embodiments of the invention will be now described with reference to the following non limiting drawings, in which: Figures la)-ld) show modules having an aerated concrete substrate in the form of a brick 30 and different arrangements of a cover layer on external surfaces of the substrate; H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -4 Figures 2a)-2b) show modules having an aerated concrete substrate in the form of a panel with a cover layer on either one surface or two opposing surfaces of the substrate, suitable for the construction of a wall structure; 5 Figure 3 shows a module having an aerated concrete substrate in the form of a panel with a cover layer on a surface, suitable for the construction of a floor structure; Figures 4a)-4c) show modules having an aerated concrete substrate in the form of a L block, with different arrangements of a cover layer fixed on external surfaces of the 10 substrate; and Figures 5a)-b) show modules having a mating grove and protrusion to facilitate mutual inter-engagement of the modules, suitable in the construction of a wall structure. 15 DETAILED DESCRIPTION OF THE INVENTION The present invention provides a prefabricated building module. As used herein, the expression 'building module' means one of a set of parts that can be connected or combined to construct a building structure, for example in the construction of residential or 20 commercial structures. By the expression 'building structure' is meant a constituting element of such a structure, such as a wall, a roof, a ceiling, a floor, stairs, etc. In this context, the building module of the invention can be therefore useful in the construction of walls, floors, ceilings, stairs and any building structures that contribute to form a complete structure. 25 Since the building module of the invention is suitable for constructing a building structure, it will be understood that the module is a self-supporting entity. By being 'self-supporting', the module of the invention is an autonomous entity that allows for the construction of a building structure with no need for a supporting frame, as opposed to cladding elements 30 such as wallboard sheets.

H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -5 In the construction of a building the module of the invention may therefore be connected directly to other modules to provide for a complete building structure and/or to modules of an adjacent building structure to provide for the complete building. For example, an interior wall may be built by connecting together several modules in the form of panels, 5 and the resulting wall can be connected directly to a floor and a ceiling structure, thus potentially eliminating the need for a supporting frame. By being 'prefabricated' is meant that the building module of the invention is provided in a ready-to-use form. The building module will invariably be produced in a location that is 10 separate from the site of intended use (e.g. a construction site). Also, by being 'prefabricated' the module of the invention can be produced independently from, and well in advance of, the actual construction of the building structure. This advantageously minimises construction time and on-site waste. 15 The building module of the invention comprises an aerated concrete substrate. The expression 'aerated concrete' is used herein to refer to a building material that in its conventional composition is the product of a steam cured aqueous mixture of cement, sand or pulverized fuel ash, lime and an aeration agent. 20 Processes for the production of aerated concrete would be known to a skilled person. A typical production process involves the initial preparation of a mixture of cement, sand, lime, and a foaming agent with water, and subsequent pouring of the mixture into a mold. The foaming agent causes bubbles to develop and remain interspersed within the mixture, which at this stage is in the form of a soft mass. While inside the mold the mixture foams 25 (typically up to about double its initial volume) is kept moist, and is allowed to set (usually about 90 minutes). After this time the foamed mixture is hard enough so that it can be moved or cut to desired dimensions. Steam curing may subsequently be applied to produce a physically rigid and chemically 30 stable concrete material with an average density usually about one fifth than that of concrete formed of a comparable mixture of precursors absent the foaming agent. The H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -6 reduced density derives from the bubbles being trapped within the solidified concrete volume to form non-connecting voids. The voids may have a major dimension of up to 3 mm. If the steam curing procedure is performed in autoclave under high steam pressure, aerated concrete also takes the name of autoclaved aerated concrete (AAC). 5 The presence of voids homogeneously dispersed within its volume gives aerated concrete unique and advantageous properties. These include good compressive strength, low weight, good thermal and acoustic insulation characteristics, and high resistance to fire. Aerated concrete has durability similar to conventional concrete or stone and is non 10 rotting, non-toxic and resistant to termites. In this context, by the expression 'aerated concrete substrate' is meant a base material made of aerated concrete that acts as a support onto which a cover layer can be fixed. Specifically, the aerated concrete substrate of the invention is monolithic. By the term 15 'monolithic' is meant that the aerated concrete substrate is a single and uniform piece of material as opposed to being made of a plurality of discrete unit blocks joined together. In other words, by being 'monolithic' the substrate of the present invention is provided as a continuous mass of aerated concrete that does not present joints or seams. For example, in the context of a typical aerated concrete production process a monolithic aerated concrete 20 substrate for the purpose of the invention would be an aerated concrete block as extracted from a mould or, if the moulded block is cut to a specific size, a resulting cut. The building module of the invention also comprises a cover layer. As used herein, the expression 'cover layer' refers to a layer of material that can be superimposed to an 25 external surface of the substrate providing for an outer skin of the substrate. There is no particular limitation as to what the cover layer is made of, provided the cover layer can be fixed to an external surface of the substrate. In the context of the invention the cover layer may be made of a discrete material or a composite material. Examples of 30 discrete materials and composite materials suitable for use as cover layer in the building module of the invention include wood (e.g. timber), wood composite board (e.g. plywood H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -7 of any grade or combinations of grades selected from N, A, B, C and D grade), reconstituted composite wood (e.g. reconstituted timber), gypsum board, Corian (i.e. acrylic polymer and alumina trihydrate composite), cork, cement-board, ceramic, porcelain, and polymer (e.g. expanded or extruded polystyrene, vinyl-based such as PVC). 5 In some embodiments the cover layer is made of hardwood, for example ash, oak, maple, mahogany, cherry, walnut, teak, or any combinations thereof. In other embodiments the cover layer is made of softwood, for example pine, hickory, beach, ash, birch, cedar, redwood, Douglas fir or any combinations thereof. In further embodiments the cover layer 10 is made of a combination of hardwood and softwood, for example a combination of one or more hardwood and softwood selected from those listed herein. In certain preferred embodiments, the cover layer is gypsum board. By the expression 'gypsum board' is meant a composite material made of gypsum plaster pressed between 15 two layers of paper or thin cardboard (also known as plasterboard, wallboard, drywall, or sheet rock). Any variety of gypsum board that may be known to a skilled person would be suitable for forming a cover layer for use in the present invention. For example, a skilled person would be familiar with gypsum board commercialised under names such as Sheetrock@, Kleenex@, or Gyproc. In addition to conventional gypsum board the gypsum 20 board for use in the invention may be provided in a composite form, for example laminated with fiberglass (e.g. DensGlass), or reinforced with dispersed fibres (e.g. cellulose fibre reinforced gypsum board). In further embodiments, the cover layer comprises a tile. Examples of tiles suitable for use 25 as the cover layer in the module of the invention include ceramic tiles, porcelain tiles, metal tiles, glass tiles, terracotta tiles and stone tiles (e.g. natural stone, slate, marble, sandstone, granite, and travertine tiles). The tiles may be glazed tiles, polished tiles, honed tiles, metal plated tiles, finger tiles, pencil tiles, mosaic tiles, printed tiles, sealed tiles, or structured tiles (e.g. tiles having any kind of three-dimensional effect or structure on their 30 surface).

H:\anh\Interwoven\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 In some embodiments the cover layer has on its surface a decorative pattern, such that when the cover is fixed to the substrate it provides the module with a finish surface bearing the decorative pattern. The decorative pattern may be a two- or three- dimensional pattern. Examples of two-dimensional decorative patterns include any printed, painted or applied 5 imagery that may be suited for interior or exterior decoration purposes, such as a customised image or drawing, a regular repetitive pattern of geometrical shapes, or a random repetitive pattern of geometrical shapes. Examples of three-dimensional decorative patterns include any three-dimensional textured imagery in the form of a three-dimensional relief pattern, carved pattern, sculpted pattern, engraved pattern, molded pattern, or 10 stamped pattern. In some embodiments, the decorative pattern is in the form of a discrete additional layer that is fixed onto at least a portion of a surface of the cover layer, for example by way of an adhesive. In some embodiments, the decorative pattern is in the form of a discrete additional layer that is fixed onto the entire extent of a surface of the cover layer. 15 There is no particular limit as to the thickness of the cover layer, provided the cover layer can be fixed to an external surface of the aerated concrete substrate. For example, the thickness of the cover layer may be at least 2.5 mm. In some embodiments, the thickness of the cover layer is up to about 5 mm, up to about 7.5 mm, up to about 10 mm, up to 20 about 12.5 mm, up to about 15 mm, up to about 17.5 mm, up to about 20 mm, up to about 22.5 mm, up to about 25 mm, or up to about 30 mm. In the building module of the invention the cover layer is fixed to an external surface of the substrate. By the cover being 'fixed' to an external surface of the substrate is meant that 25 the cover is secured to a surface of the substrate such that there is no relative movement between the substrate and the cover. A skilled person would be aware of appropriate fixing means suitable for fixing the cover layer to an external surface of an aerated concrete substrate. 30 In some embodiments, the cover layer is fixed to an external surface of an aerated concrete substrate by way of an adhesive. Examples of suitable adhesive include laminating H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -9 adhesives, such as joint compound adhesives, drywall contact, or modified contact adhesives. In some embodiments, the adhesive is a joint compound. This may be either dry powder 5 setting-type or ready mixed drying type. If a dry powder setting-type adhesive is used the adhesive may be activated by a solvent, for example water, used for mixing the adhesive compound. In some embodiments, the adhesive is drywall contact or modified contact. Modified contact adhesives advantageously provide good long-term strength with sufficient immediate bond to permit attachment without temporary fasteners. In addition, a 10 modified contact adhesive has bridging ability. Provided the adhesive fixes any of the cover layers listed herein to a surface of an aerated concrete substrate, there is no limitation as to the specific formulation of the adhesive. For example, adhesives suitable for use in the present invention may include wood glue, 15 contact adhesive, construction adhesive, resin, melted glue, and expanded foam. In some embodiments, the adhesive is an acrylic, epoxy, polyurethane, polyethylene adhesive, or any combinations thereof. For example, the adhesive is fast cure and low expansion polyurethane or polyurethane paste. 20 In some embodiments the adhesive contains ethylene vinyl acetate, propylene vinyl acetate or mixtures thereof. Ethylene vinyl acetate and propylene vinyl acetate copolymers are well known commercially available materials. Reference example procedures for their preparation are described in US 2,200,429 and US 2,396,785, the contents of which are included herein in their entirety. The amount of vinyl acetate in the copolymer may be in 25 the range of from about 4% to about 80% by weight. The vinyl acetate copolymer may be alcohol or surfactant stabilized. In some embodiments the adhesive contains polyvinyl alcohol, which may be provided in a partially hydrolyzed form. For example, the degree of hydrolysis of the polyvinyl alcohol 30 may be at least about 85%, at least about 90%, at least about 98%.

H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 10 In some embodiments, the adhesive comprises a filler in its formulation. Example of suitable fillers would be known to a skilled person, and include polysaccarides, calcium carbonate, clay, limestone, kaolin, mica, nut shell flours, silica, talc and wood flour. 5 In some embodiments the adhesive comprises additives in its formulation. Examples of suitable additives include plasticizers, acids, waxes, synthetic resins, tackifiers, defoamers, preservatives, bases such as sodium hydroxide, dyes, pigments, UV indicators, and other additives commonly used in the art. 10 The adhesive may also contain a surface-active agent. Suitable surface-active agents include anionic, cationic, amphoteric, nonionic surfactants, and mixtures thereof. Examples of anionic surfactants include, alkyl sulfonates, alkylaryl sulfonates, alkyl sulfates, sulfates of hydroxylalkanols, alkyl and alkylaryl disulfonates, sulfonated fatty acids, sulfates and phosphates of polyethoxylated alkanols and alkylphenols, and esters of 15 sulfosuccinic acid. Examples of cationic surfactants include alkyl quaternary ammonium salts, and alkyl quaternary phosphonium salts. Examples of non-ionic surfactants include ethylene oxide adducted to straight-chain and branched-chain alkanols, alkylphenols, higher fatty acids, higher fatty acid amines, primary or secondary higher alkyl amines, block copolymers of propylene oxide with ethylene oxide, and mixtures thereof. In some 20 embodiments, the surface active agent is added in an amount up to about 20%, of from about 0.05 to about 20%, or from 0.2 to 2% by weight, based on the adhesive composition as a whole. In some embodiments, the adhesive contains a preservative agent in its formulation. 25 Examples of suitable preservative agents include benzoates, amides and fluorides such as sodium fluoride, and hydroxybenzoic acid esters such as p-hydroxybenzoic acid methyl ester and p-hydroxybenzoic butyl ester. The preservative will generally be included in amounts of from 0.05% to about 0.2% by weight. 30 In certain embodiments the adhesive comprises a vinyl acetate copolymer, a polyvinyl alcohol and, optionally, at least one filler selected from the ones described herein. The H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 11 adhesive may comprise from about 15% to about 50% by weight of the vinyl acetate component and from about 3% to about 7% by weight of the polyvinyl alcohol component. The filler may be used in an amount of from about 2% up to about 30% by weight. 5 In an embodiment, the adhesive is a combination of limestone (10-30% by weight), kaolin (10-30% by weight), silica (0.1-1% by weight), penta-erythritol ester of rosin (1-5% by weight), methyl acetate (1-5% by weight) and acetone (10-30% by weight). In a further embodiment, the adhesive is a combination of talc (30-60% by weight), 10 methylenebis-phenylisocyanate (10-30% by weight), Cll-25 linear alkyl (5-10% by weight), methylene bisphenyl isocyanate (1-5% by weight), isocyanic acid, polymethylenepolyphenylene ester (1-5% by weight). In another embodiment the adhesive is a combination of limestone (30-60% by weight), 15 acetone (1-5% by weight), kaolin (1-5% by weight), urea (1-5% by weight), ethanol (1-5% by weight) and quartz (0.1-1% by weight). In a further embodiment the adhesive is a combination of limestone (30-60% by weight), kaolin (1-5% by weight), ethylene glycol (1-5% by weight) and quartz (0.1-1% by weight). 20 In another embodiment the adhesive is a combination of limestone (30-60% by weight), acetone (10-30% by weight), kaolin (10-30% by weight), methyl acetate (1-5% by weight), titanium dioxide (0.1-1% by weight) and quartz (0.1-1% by weight). 25 In another embodiment the adhesive is a combination of limestone (30-60% by weight), C 6 isoalkanes (10-30% by weight), rosin ester (10-30% by weight), kaolin (5-10% by weight), titanium dioxide (0.1-1% by weight), quartz (0.1-1% by weight) and naphthalene (0.1-1% by weight). 30 In another embodiment the adhesive is a combination of limestone (30-60% by weight), ethylene glycol (1-5% by weight) and quartz (0.1-1% by weight).

H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 12 In some embodiments, the cover layer is fixed to an external surface of an aerated concrete substrate by way of mechanical fastening elements. A skilled person would be aware of mechanical fastening elements suitable for fixing the cover layer to a surface of the aerated 5 concrete. In this context there is no limitation as to what constitutes a mechanical fastening element for the purpose of the invention, provided it fixes the cover layer to an external surface of the aerated concrete substrate. Examples of mechanical fastening elements include expansion bolts with universal style 10 collars (e.g. stud anchors with nuts and washers), lag shields in combination with lag bolts, screw (e.g. concrete screws), self-drilling drywall anchors, screw and anchor systems, and a combination thereof. In some embodiments the mechanical fastening elements comprise a screw. Screws 15 suitable for use in the invention include phillips pan head screws, star drive pan head screws, phillips flat headscrews, slotted flat headscrews, star drive flat headscrews, phillips oval headscrews, slotted oval headscrews, phillips truss headscrews, slotted truss headscrews, combo truss headscrews, star drive truss headscrews, slotted round headscrews, combo round headscrews, star drive pan head type F screws, star drive flat 20 head type F screws, slotted hex washer head type F screws, and a combination thereof. In some embodiments the mechanical fastening elements comprise a flange bolt or a lag bolt. Examples of flange bolts suitable for use in the invention include partial thread flange bolts, full thread flange bolts, serrated full thread flange bolts, oversize/serrated full thread 25 flange bolts, or a combination thereof. Examples of lag bolts include hex head lag bolts, hex flange head lag bolts, and a combination thereof. In some embodiments the mechanical fastening elements comprise a nut. Examples of nuts suitable for use in the invention include hex nuts, hex machine screw nuts, hex lock nuts 30 with nylon insert, hex jam nuts, hex jam nylon lock nuts, heavy hex nuts, wing nuts, cap nuts, acorn nuts, square nuts, K-lock nuts, prevailing torque lock nuts, top lock nuts, two- H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 13 way reversible lock nuts, pin-lock nuts, T-nuts, coupling nuts, slotted nuts, castle nuts, flange nuts, serrated flange nuts, oversize serrated flange nuts, nylon insert flange nuts, prevailing torque flange nuts, and a combination thereof. 5 In some embodiments the mechanical fastening elements comprise a washer. Examples of washers suitable for use in the invention include flat washers, USS flat washers, SAE flat washers, fender washers, lock washers, high collar lock washers, lock washers external tooth, lock washers internal tooth, finishing washers, dock washers, square dock washers, ogee washers, bonded sealing washers, and a combination thereof. 10 In some embodiments the mechanical fastening elements comprise an anchor. Examples of anchor suitable for use in the invention include sleeve anchors, machine screw anchors, drop-in anchors, double-expansion sleeves, spring toggle wings, plastic toggle anchors, kaptoggle, conical anchors, woodscrew anchors, hollow wall anchors, nail drive anchors, 15 and a combination thereof. Provided the mechanical fastening elements fix the cover layer to a surface of the aerated concrete substrate, there is no limitation as to the material they are made of. For example, the mechanical fastening elements (or constituting parts thereof) may be made of materials 20 selected from steel (e.g. stainless steel 18-8, stainless steel 304, stainless steel 316, stainless steel 410, zinc plated steel, chrome plated steel, hot dipped galvanized steel, blue coated steel), zinc alloys (e.g. die cast zinc alloy, zinc and lead alloy), silicon bronze, brass, and polymer. 25 In some embodiments, the mechanical fastening elements are used in combination with the adhesive to fix the cover layer to a surface of the aerated concrete substrate. In the context of the present invention it will be understood that the overall geometrical shape of the building module is dictated by the geometrical shape of the aerated concrete 30 substrate. There is no limitation to the shape of the aerated concrete substrate for use in the invention, provided the resulting building module is suitable for the construction of a H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 14 building element of the kind described herein. For example, the aerated concrete substrate may be provided in the form of brick, panel, beam, column, lintel, U- block, or L- block. In some embodiments, the aerated concrete substrate is provided in the shape of a brick. A 5 skilled person would be aware of brick shapes commonly used for the construction of building elements, for example walls. Examples of suitable brick shape include that of common parallelepiped brick, bullnose brick, coping brick, cownose brick, curved sector brick, hollow brick, perforated brick, and any purpose-made brick. 10 By the expression 'common parallelepiped brick' is meant a brick shaped as a prism whose faces are all parallelograms, for example a rectangular cuboid brick. The expression 'bullnose brick' is used to indicate a brick moulded with a rounded angle used for a rounded quoin (i.e. a connection which is formed when a wall takes a turn). The expression 'coping brick' is used to indicate a bricks made to suit the thickness of a wall on which 15 coping is to be provided. Such bricks may take various forms such as chamfered, half round or saddle-back. The expression 'cownose brick' indicates a brick moulded with a double bullnose on end, while the expression 'curved sector brick' indicates a brick in the form of curved sector which may be used in the construction of circular brick masonry pillar, brick chimneys, etc. The expression 'hollow brick' is used to indicate a brick 20 containing a pattern of large holes that may extend throughout the brick's volume, and that occupy at least 25% of the brick's volume (also known as 'cellular' or 'cavity' bricks). The expression 'perforated brick' is used to indicate a brick containing cylindrical holes throughout its thickness. In a perforated brick the distance between the side of brick and edge of perforation may be at least 15 mm, and the distance between the edges of 25 successive perforations may be at least 10 mm. The expression 'purpose-made brick' is used to indicate a customised brick that is manufactured in order to achieve a specific purpose. For example, a splay or cant brick made made for jambs of doors and windows, an arch brick made of wedge shape to keep mortar joint of uniform thickness, an ornamental brick prepared for assembling corbels, cornices, etc. 30 H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 15 There is no limitation as to the actual dimensions of the aerated concrete substrate when provided in the form of a brick. In some embodiments, the aerated concrete substrate is provided in the form of a brick having a width of at least about 70 mm, at least about 80 mm, at least about 90 mm, at least about 100 mm, at least about 110 mm, at least about 120 5 mm, at least about 130 mm, at least about 140 mm, at least about 150 mm, at least about 160 mm, at least about 170 mm, at least about 180 mm, at least about 190 mm, at least about 200 mm, at least about 210 mm, at least about 220 mm, at least about 230 mm, at least about 240 mm, or at least about 250 mm. In some embodiments, the aerated concrete substrate is provided in the form of a brick having a width of up to about 300 mm. 10 In some embodiments, the aerated concrete substrate is provided in the form of a brick having a height of at least about 30 mm, at least about 40 mm, at least about 50 mm, at least about 60 mm, at least about 70 mm, at least about 80 mm, at least about 90 mm, at least about 100 mm, at least about 110 mm, at least about 120 mm, at least about 130 mm, 15 at least about 140 mm, at least about 150 mm, at least about 160 mm, at least about 170 mm, at least about 180 mm, at least about 190 mm, at least about 200 mm, at least about 210 mm, at least about 220 mm, at least about 230 mm, at least about 240 mm, or at least about 250 mm. In some embodiments, the aerated concrete substrate is provided in the form of a brick having a height of up to about 300 mm. 20 In some embodiments, the aerated concrete substrate is provided in the form of a brick having a length of at least about 30 mm, at least about 50 mm, at least about 75 mm, at least about 100 mm, at least about 125 mm, at least about 150 mm, at least about 175 mm, at least about 200 mm, at least about 225 mm, at least about 250 mm, at least about 275 25 mm, at least about 300 mm, at least about 325 mm, at least about 350 mm, at least about 375 mm, at least about 400 mm, at least about 425 mm, at least about 450 mm, at least about 475 mm, at least about 500 mm, at least about 525 mm, at least about 550 mm, at least about 575 mm, at least about 600 mm, at least about 625 mm, at least about 650 mm, at least about 675 mm, at least about 700 mm, at least about 725 mm, at least about 750 30 mm, at least about 775 mm, at least about 800 mm, at least about 825 mm, at least about 850 mm, at least about 875 mm, at least about 900 mm, at least about 925 mm, at least H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 16 about 950 mm, at least about 975 mm, at least about 1,000 mm, at least about 1,125 mm, at least about 1,150 mm, at least about 1,175 mm, at least about 1,200 mm, at least about 1,225 mm, at least about 1,250 mm, at least about 1,275 mm, at least about 1,300 mm, at least about 1,325 mm, at least about 1,350 mm, at least about 1,375 mm, at least about 5 1,400 mm, at least about 1,425 mm, at least about 1,450 mm, at least about 1,475 mm, at least about 1,500 mm, at least about 1,525 mm, at least about 1,550 mm, at least about 1,575 mm, or at least about 1,600 mm. In some embodiments, the aerated concrete substrate is provided in the form of a brick having a length of up to 2,000 mm. 10 In some embodiments, the aerated concrete substrate is provided in the form of a panel. The term 'panel' as used herein means a flat piece of construction material made to form part of a surface. There is no limitation as to the dimensions of the substrate when provided in the form of a panel, provided the resulting building module is suitable for the construction of a building element as described herein. 15 In some embodiments, the aerated concrete substrate is provided as a panel having a width of at least about 50 mm, at least about 100 mm, at least about 150 mm, at least about 200 mm, at least about 250 mm, at least about 300 mm, at least about 350 mm, at least about 400 mm, at least about 500 mm, at least about 550 mm, at least about 600 mm, at least 20 about 650 mm, at least about 700 mm, at least about 750 mm, at least about 800 mm, at least about 850 mm, at least about 900 mm, at least about 1,000 mm, at least about 1,100 mm, at least about 1,150 mm, at least about 1,200 mm, at least about 1,250 mm, at least about 1,300 mm, at least about 1,350 mm, at least about 1,400 mm, at least about 1,500 mm, at least about 1,550 mm, at least about 1,600 mm, at least about 1,650 mm, at least 25 about 1,700 mm, at least about 1,750 mm, at least about 1,800 mm, at least about 1,850 mm, at least about 1,900 mm, at least about 2,000 mm, at least about 2,100 mm, at least about 2,150 mm, at least about 2,200 mm, at least about 2,250 mm, at least about 2,300 mm, at least about 2,350 mm, at least about 2,400 mm, at least about 2,500 mm, at least about 2,550 mm, at least about 2,600 mm, at least about 2,650 mm, at least about 2,700 30 mm, at least about 2,750 mm, at least about 2,800 mm, at least about 2,850 mm, at least about 2,900 mm, at least about 3,000 mm, at least about 3,100 mm, at least about 3,150 H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 17 mm, at least about 3,200 mm, at least about 3,250 mm, at least about 3,300 mm, at least about 3,350 mm, at least about 3,400 mm, at least about 3,500 mm, at least about 3,550 mm, at least about 3,600 mm, at least about 3,650 mm, at least about 3,700 mm, at least about 3,750 mm, at least about 3,800 mm, at least about 3,850 mm, at least about 3,900 5 mm, or at least about 4,000 mm. In some embodiments, the aerated concrete substrate is provided as a panel having a width of up to 7,000 mm. In some embodiments, the aerated concrete substrate is provided as a panel having a thickness of at least about 5 mm. For example, the aerated concrete substrate is provided as 10 a panel having a thickness of up to about 10 mm, up to about 50 mm, up to about 100 mm, up to about 150 mm, up to about 200 mm, up to about 250 mm, up to about 300 mm, up to about 350 mm, up to about 400 mm, up to about 450 mm, up to about 500 mm, up to about 550 mm, up to about 600 mm, up to about 650 mm, up to about 700 mm, up to about 750 mm, or up to about 800 mm. 15 In some embodiments, the aerated concrete substrate is provided as a panel having a length of at least about 50 mm, at least about 100 mm, at least about 150 mm, at least about 200 mm, at least about 250 mm, at least about 300 mm, at least about 350 mm, at least about 400 mm, at least about 500 mm, at least about 550 mm, at least about 600 mm, at least 20 about 650 mm, at least about 700 mm, at least about 750 mm, at least about 800 mm, at least about 850 mm, at least about 900 mm, at least about 1,000 mm, at least about 1,100 mm, at least about 1,150 mm, at least about 1,200 mm, at least about 1,250 mm, at least about 1,300 mm, at least about 1,350 mm, at least about 1,400 mm, at least about 1,500 mm, at least about 1,550 mm, at least about 1,600 mm, at least about 1,650 mm, at least 25 about 1,700 mm, at least about 1,750 mm, at least about 1,800 mm, at least about 1,850 mm, at least about 1,900 mm, at least about 2,000 mm, at least about 2,100 mm, at least about 2,150 mm, at least about 2,200 mm, at least about 2,250 mm, at least about 2,300 mm, at least about 2,350 mm, at least about 2,400 mm, at least about 2,500 mm, at least about 2,550 mm, at least about 2,600 mm, at least about 2,650 mm, at least about 2,700 30 mm, at least about 2,750 mm, at least about 2,800 mm, at least about 2,850 mm, at least about 2,900 mm, at least about 3,000 mm, at least about 3,100 mm, at least about 3,150 H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 18 mm, at least about 3,200 mm, at least about 3,250 mm, at least about 3,300 mm, at least about 3,350 mm, at least about 3,400 mm, at least about 3,500 mm, at least about 3,550 mm, at least about 3,600 mm, at least about 3,650 mm, at least about 3,700 mm, at least about 3,750 mm, at least about 3,800 mm, at least about 3,850 mm, at least about 3,900 5 mm, or at least about 4,000 mm. In some embodiments, the aerated concrete substrate is provided as a panel having a length of up to 7,000 mm. For example, the aerated concrete substrate may be provided in the form of a panel which dimensions are about (when expressed as width x thickness x length) 600mm x 75mm x 10 1,000mm, 600mm x 75mm x 1,100mm, 600mm x 75mm x 1,200mm, 600mm x 75mm x 1,300mm, 600mm x 75mm x 1,400mm, 600mm x 75mm x 1,500mm, 600mm x 75mm x 1,600mm, 600mm x 75mm x 1,700mm, 600mm x 75mm x 1,800mm, 600mm x 75mm x 1,900mm, 600mm x 75mm x 2,000mm, 600mm x 75mm x 2,100mm, 600mm x 75mm x 2,200mm, 600mm x 75mm x 2,300mm, 600mm x 75mm x 2,400mm, 600mm x 75mm x 15 2,500mm, 600mm x 75mm x 2,600mm, 600mm x 75mm x 2,700mm, 600mm x 75mm x 2,800mm, 600mm x 75mm x 2,900mm, 600mm x 75mm x 3,000mm, 600mm x 75mm x 3,100mm, 600mm x 75mm x 3,200mm, 600mm x 75mm x 3,300mm, 600mm x 75mm x 3,400mm, 600mm x 75mm x 3,500mm, 600mm x 75mm x 3,600mm, 600mm x 75mm x 3,700mm, 600mm x 75mm x 3,800mm, 600mm x 75mm x 3,900mm, 600mm x 75mm x 20 4,000mm, 600mm x 75mm x 4,100mm, 600mm x 75mm x 4,200mm, 600mm x 75mm x 4,300mm, 600mm x 75mm x 4,400mm, 600mm x 75mm x 4,500mm, 600mm x 75mm x 4,600mm, 600mm x 75mm x 4,700mm, 600mm x 75mm x 4,800mm, 600mm x 75mm x 4,900mm, 600mm x 75mm x 5,000mm, 600mm x 75mm x 5,100mm, 600mm x 75mm x 5,200mm, 600mm x 75mm x 5,300mm, 600mm x 75mm x 5,400mm, 600mm x 75mm x 25 5,500mm, 600mm x 75mm x 5,600mm, 600mm x 75mm x 5,700mm, 600mm x 75mm x 5,800mm, 600mm x 75mm x 5,900mm, 600mm x 75mm x 6,000mm, 600mm x 75mm x 6,100mm, 600mm x 75mm x 6,200mm, 600mm x 75mm x 6,300mm, 600mm x 75mm x 6,400mm, 600mm x 75mm x 6,500mm, 600mm x 75mm x 6,600mm, 600mm x 75mm x 6,700mm, 600mm x 75mm x 6,800mm, 600mm x 75mm x 6,900mm, or 600mm x 75mm 30 x 7,000mm.

H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 - 19 As a further example, the aerated concrete substrate may be provided in the form of a panel which dimensions are about (when expressed as width x thickness x length) 600mm x 100mm x 1,000mm, 600mm x 100mm x 1,100mm, 600mm x 100mm x 1,200mm, 600mm x 100mm x 1,300mm, 600mm x 100mm x 1,400mm, 600mm x 100mm x 1,500mm, 5 600mm x 100mm x 1,600mm, 600mm x 100mm x 1,700mm, 600mm x 100mm x 1,800mm, 600mm x 100mm x 1,900mm, 600mm x 100mm x 2,000mm, 600mm x 100mm x 2,100mm, 600mm x 100mm x 2,200mm, 600mm x 100mm x 2,300mm, 600mm x 100mm x 2,400mm, 600mm x 100mm x 2,500mm, 600mm x 100mm x 2,600mm, 600mm x 100mm x 2,700mm, 600mm x 100mm x 2,800mm, 600mm x 100mm x 2,900mm, 10 600mm x 100mm x 3,000mm, 600mm x 100mm x 3,100mm, 600mm x 100mm x 3,200mm, 600mm x 100mm x 3,300mm, 600mm x 100mm x 3,400mm, 600mm x 100mm x 3,500mm, 600mm x 100mm x 3,600mm, 600mm x 100mm x 3,700mm, 600mm x 100mm x 3,800mm, 600mm x 100mm x 3,900mm, 600mm x 100mm x 4,000mm, 600mm x 100mm x 4,100mm, 600mm x 100mm x 4,200mm, 600mm x 100mm x 4,300mm, 15 600mm x 100mm x 4,400mm, 600mm x 100mm x 4,500mm, 600mm x 100mm x 4,600mm, 600mm x 100mm x 4,700mm, 600mm x 100mm x 4,800mm, 600mm x 100mm x 4,900mm, 600mm x 100mm x 5,000mm, 600mm x 100mm x 5,100mm, 600mm x 100mm x 5,200mm, 600mm x 100mm x 5,300mm, 600mm x 100mm x 5,400mm, 600mm x 100mm x 5,500mm, 600mm x 100mm x 5,600mm, 600mm x 100mm x 5,700mm, 20 600mm x 100mm x 5,800mm, 600mm x 100mm x 5,900mm, 600mm x 100mm x 6,000mm, 600mm x 100mm x 6,100mm, 600mm x 100mm x 6,200mm, 600mm x 100mm x 6,300mm, 600mm x 100mm x 6,400mm, 600mm x 100mm x 6,500mm, 600mm x 100mm x 6,600mm, 600mm x 100mm x 6,700mm, 600mm x 100mm x 6,800mm, 600mm x 100mm x 6,900mm, or 600mm x 100mm x 7,000mm. 25 As a further example, the aerated concrete substrate may be provided in the form of a panel which dimensions are about (when expressed as width x thickness x length) 600mm x 200mm x 1,000mm, 600mm x 200mm x 1,200mm, 600mm x 200mm x 1,200mm, 600mm x 200mm x 1,300mm, 600mm x 200mm x 1,400mm, 600mm x 200mm x 1,500mm, 30 600mm x 200mm x 1,600mm, 600mm x 200mm x 1,700mm, 600mm x 200mm x 1,800mm, 600mm x 200mm x 1,900mm, 600mm x 200mm x 2,000mm, 600mm x 200mm H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 20 x 2,200mm, 600mm x 200mm x 2,200mm, 600mm x 200mm x 2,300mm, 600mm x 200mm x 2,400mm, 600mm x 200mm x 2,500mm, 600mm x 200mm x 2,600mm, 600mm x 200mm x 2,700mm, 600mm x 200mm x 2,800mm, 600mm x 200mm x 2,900mm, 600mm x 200mm x 3,000mm, 600mm x 200mm x 3,200mm, 600mm x 200mm x 5 3,200mm, 600mm x 200mm x 3,300mm, 600mm x 200mm x 3,400mm, 600mm x 200mm x 3,500mm, 600mm x 200mm x 3,600mm, 600mm x 200mm x 3,700mm, 600mm x 200mm x 3,800mm, 600mm x 200mm x 3,900mm, 600mm x 200mm x 4,000mm, 600mm x 200mm x 4,200mm, 600mm x 200mm x 4,200mm, 600mm x 200mm x 4,300mm, 600mm x 200mm x 4,400mm, 600mm x 200mm x 4,500mm, 600mm x 200mm x 10 4,600mm, 600mm x 200mm x 4,700mm, 600mm x 200mm x 4,800mm, 600mm x 200mm x 4,900mm, 600mm x 200mm x 5,000mm, 600mm x 200mm x 5,200mm, 600mm x 200mm x 5,200mm, 600mm x 200mm x 5,300mm, 600mm x 200mm x 5,400mm, 600mm x 200mm x 5,500mm, 600mm x 200mm x 5,600mm, 600mm x 200mm x 5,700mm, 600mm x 200mm x 5,800mm, 600mm x 200mm x 5,900mm, 600mm x 200mm x 15 6,000mm, 600mm x 200mm x 6,200mm, 600mm x 200mm x 6,200mm, 600mm x 200mm x 6,300mm, 600mm x 200mm x 6,400mm, 600mm x 200mm x 6,500mm, 600mm x 200mm x 6,600mm, 600mm x 200mm x 6,700mm, 600mm x 200mm x 6,800mm, 600mm x 200mm x 6,900mm, or 600mm x 200mm x 7,000mm. 20 As a further example, the aerated concrete substrate may be provided in the form of a panel which dimensions are about (when expressed as width x thickness x length) 600mm x 300mm x 1,000mm, 600mm x 300mm x 1,300mm, 600mm x 300mm x 1,200mm, 600mm x 300mm x 1,300mm, 600mm x 300mm x 1,400mm, 600mm x 300mm x 1,500mm, 600mm x 300mm x 1,600mm, 600mm x 300mm x 1,700mm, 600mm x 300mm x 25 1,800mm, 600mm x 300mm x 1,900mm, 600mm x 300mm x 2,000mm, 600mm x 300mm x 2,300mm, 600mm x 300mm x 2,200mm, 600mm x 300mm x 2,300mm, 600mm x 300mm x 2,400mm, 600mm x 300mm x 2,500mm, 600mm x 300mm x 2,600mm, 600mm x 300mm x 2,700mm, 600mm x 300mm x 2,800mm, 600mm x 300mm x 2,900mm, 600mm x 300mm x 3,000mm, 600mm x 300mm x 3,300mm, 600mm x 300mm x 30 3,200mm, 600mm x 300mm x 3,300mm, 600mm x 300mm x 3,400mm, 600mm x 300mm x 3,500mm, 600mm x 300mm x 3,600mm, 600mm x 300mm x 3,700mm, 600mm x H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 21 300mm x 3,800mm, 600mm x 300mm x 3,900mm, 600mm x 300mm x 4,000mm, 600mm x 300mm x 4,300mm, 600mm x 300mm x 4,200mm, 600mm x 300mm x 4,300mm, 600mm x 300mm x 4,400mm, 600mm x 300mm x 4,500mm, 600mm x 300mm x 4,600mm, 600mm x 300mm x 4,700mm, 600mm x 300mm x 4,800mm, 600mm x 300mm 5 x 4,900mm, 600mm x 300mm x 5,000mm, 600mm x 300mm x 5,300mm, 600mm x 300mm x 5,200mm, 600mm x 300mm x 5,300mm, 600mm x 300mm x 5,400mm, 600mm x 300mm x 5,500mm, 600mm x 300mm x 5,600mm, 600mm x 300mm x 5,700mm, 600mm x 300mm x 5,800mm, 600mm x 300mm x 5,900mm, 600mm x 300mm x 6,000mm, 600mm x 300mm x 6,300mm, 600mm x 300mm x 6,200mm, 600mm x 300mm 10 x 6,300mm, 600mm x 300mm x 6,400mm, 600mm x 300mm x 6,500mm, 600mm x 300mm x 6,600mm, 600mm x 300mm x 6,700mm, 600mm x 300mm x 6,800mm, 600mm x 300mm x 6,900mm, or 600mm x 300mm x 7,000mm. As a further example, the aerated concrete substrate may be provided in the form of a panel 15 which dimensions are about (when expressed as width x thickness x length) 600mm x 350mm x 1,000mm, 600mm x 350mm x 1,350mm, 600mm x 350mm x 1,200mm, 600mm x 350mm x 1,300mm, 600mm x 350mm x 1,400mm, 600mm x 350mm x 1,500mm, 600mm x 350mm x 1,600mm, 600mm x 350mm x 1,700mm, 600mm x 350mm x 1,800mm, 600mm x 350mm x 1,900mm, 600mm x 350mm x 2,000mm, 600mm x 350mm 20 x 2,350mm, 600mm x 350mm x 2,200mm, 600mm x 350mm x 2,300mm, 600mm x 350mm x 2,400mm, 600mm x 350mm x 2,500mm, 600mm x 350mm x 2,600mm, 600mm x 350mm x 2,700mm, 600mm x 350mm x 2,800mm, 600mm x 350mm x 2,900mm, 600mm x 350mm x 3,000mm, 600mm x 350mm x 3,350mm, 600mm x 350mm x 3,200mm, 600mm x 350mm x 3,300mm, 600mm x 350mm x 3,400mm, 600mm x 350mm 25 x 3,500mm, 600mm x 350mm x 3,600mm, 600mm x 350mm x 3,700mm, 600mm x 350mm x 3,800mm, 600mm x 350mm x 3,900mm, 600mm x 350mm x 4,000mm, 600mm x 350mm x 4,350mm, 600mm x 350mm x 4,200mm, 600mm x 350mm x 4,300mm, 600mm x 350mm x 4,400mm, 600mm x 350mm x 4,500mm, 600mm x 350mm x 4,600mm, 600mm x 350mm x 4,700mm, 600mm x 350mm x 4,800mm, 600mm x 350mm 30 x 4,900mm, 600mm x 350mm x 5,000mm, 600mm x 350mm x 5,350mm, 600mm x 350mm x 5,200mm, 600mm x 350mm x 5,300mm, 600mm x 350mm x 5,400mm, 600mm H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 22 x 350mm x 5,500mm, 600mm x 350mm x 5,600mm, 600mm x 350mm x 5,700mm, 600mm x 350mm x 5,800mm, 600mm x 350mm x 5,900mm, 600mm x 350mm x 6,000mm, 600mm x 350mm x 6,350mm, 600mm x 350mm x 6,200mm, 600mm x 350mm x 6,300mm, 600mm x 350mm x 6,400mm, 600mm x 350mm x 6,500mm, 600mm x 5 350mm x 6,600mm, 600mm x 350mm x 6,700mm, 600mm x 350mm x 6,800mm, 600mm x 350mm x 6,900mm, or 600mm x 350mm x 7,000mm. For example, the aerated concrete substrate may be provided in the form of a panel which dimensions are about (when expressed as width x thickness x length) 1,000mm x 75mm x 10 1,000mm, 1,000mm x 75mm x 1,100mm, 1,000mm x 75mm x 1,200mm, 1,000mm x 75mm x 1,300mm, 1,000mm x 75mm x 1,400mm, 1,000mm x 75mm x 1,500mm, 1,000mm x 75mm x 1,300mm, 1,000mm x 75mm x 1,700mm, 1,000mm x 75mm x 1,800mm, 1,000mm x 75mm x 1,900mm, 1,000mm x 75mm x 2,000mm, 1,000mm x 75mm x 2,100mm, 1,000mm x 75mm x 2,200mm, 1,000mm x 75mm x 2,300mm, 15 1,000mm x 75mm x 2,400mm, 1,000mm x 75mm x 2,500mm, 1,000mm x 75mm x 2,300mm, 1,000mm x 75mm x 2,700mm, 1,000mm x 75mm x 2,800mm, 1,000mm x 75mm x 2,900mm, 1,000mm x 75mm x 3,000mm, 1,000mm x 75mm x 3,100mm, 1,000mm x 75mm x 3,200mm, 1,000mm x 75mm x 3,300mm, 1,000mm x 75mm x 3,400mm, 1,000mm x 75mm x 3,500mm, 1,000mm x 75mm x 3,300mm, 1,000mm x 20 75mm x 3,700mm, 1,000mm x 75mm x 3,800mm, 1,000mm x 75mm x 3,900mm, 1,000mm x 75mm x 4,000mm, 1,000mm x 75mm x 4,100mm, 1,000mm x 75mm x 4,200mm, 1,000mm x 75mm x 4,300mm, 1,000mm x 75mm x 4,400mm, 1,000mm x 75mm x 4,500mm, 1,000mm x 75mm x 4,300mm, 1,000mm x 75mm x 4,700mm, 1,000mm x 75mm x 4,800mm, 1,000mm x 75mm x 4,900mm, 1,000mm x 75mm x 25 5,000mm, 1,000mm x 75mm x 5,100mm, 1,000mm x 75mm x 5,200mm, 1,000mm x 75mm x 5,300mm, 1,000mm x 75mm x 5,400mm, 1,000mm x 75mm x 5,500mm, 1,000mm x 75mm x 5,300mm, 1,000mm x 75mm x 5,700mm, 1,000mm x 75mm x 5,800mm, 1,000mm x 75mm x 5,900mm, 1,000mm x 75mm x 6,000mm, 1,000mm x 75mm x 6,100mm, 1,000mm x 75mm x 6,200mm, 1,000mm x 75mm x 6,300mm, 30 1,000mm x 75mm x 6,400mm, 1,000mm x 75mm x 6,500mm, 1,000mm x 75mm x H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 23 6,300mm, 1,000mm x 75mm x 6,700mm, 1,000mm x 75mm x 6,800mm, 1,000mm x 75mm x 6,900mm, or 1,000mm x 75mm x 7,000mm. For example, the aerated concrete substrate may be provided in the form of a panel which 5 dimensions are about (when expressed as width x thickness x length) 1,500mm x 75mm x 1,000mm, 1,500mm x 75mm x 1,100mm, 1,500mm x 75mm x 1,200mm, 1,500mm x 75mm x 1,300mm, 1,500mm x 75mm x 1,400mm, 1,500mm x 75mm x 1,500mm, 1,500mm x 75mm x 1,300mm, 1,500mm x 75mm x 1,700mm, 1,500mm x 75mm x 1,800mm, 1,500mm x 75mm x 1,900mm, 1,500mm x 75mm x 2,000mm, 1,500mm x 10 75mm x 2,100mm, 1,500mm x 75mm x 2,200mm, 1,500mm x 75mm x 2,300mm, 1,500mm x 75mm x 2,400mm, 1,500mm x 75mm x 2,500mm, 1,500mm x 75mm x 2,300mm, 1,500mm x 75mm x 2,700mm, 1,500mm x 75mm x 2,800mm, 1,500mm x 75mm x 2,900mm, 1,500mm x 75mm x 3,000mm, 1,500mm x 75mm x 3,100mm, 1,500mm x 75mm x 3,200mm, 1,500mm x 75mm x 3,300mm, 1,500mm x 75mm x 15 3,400mm, 1,500mm x 75mm x 3,500mm, 1,500mm x 75mm x 3,300mm, 1,500mm x 75mm x 3,700mm, 1,500mm x 75mm x 3,800mm, 1,500mm x 75mm x 3,900mm, 1,500mm x 75mm x 4,000mm, 1,500mm x 75mm x 4,100mm, 1,500mm x 75mm x 4,200mm, 1,500mm x 75mm x 4,300mm, 1,500mm x 75mm x 4,400mm, 1,500mm x 75mm x 4,500mm, 1,500mm x 75mm x 4,300mm, 1,500mm x 75mm x 4,700mm, 20 1,500mm x 75mm x 4,800mm, 1,500mm x 75mm x 4,900mm, 1,500mm x 75mm x 5,000mm, 1,500mm x 75mm x 5,100mm, 1,500mm x 75mm x 5,200mm, 1,500mm x 75mm x 5,300mm, 1,500mm x 75mm x 5,400mm, 1,500mm x 75mm x 5,500mm, 1,500mm x 75mm x 5,300mm, 1,500mm x 75mm x 5,700mm, 1,500mm x 75mm x 5,800mm, 1,500mm x 75mm x 5,900mm, 1,500mm x 75mm x 6,000mm, 1,500mm x 25 75mm x 6,100mm, 1,500mm x 75mm x 6,200mm, 1,500mm x 75mm x 6,300mm, 1,500mm x 75mm x 6,400mm, 1,500mm x 75mm x 6,500mm, 1,500mm x 75mm x 6,300mm, 1,500mm x 75mm x 6,700mm, 1,500mm x 75mm x 6,800mm, 1,500mm x 75mm x 6,900mm, or 1,500mm x 75mm x 7,000mm. 30 In the building module of the invention the cover layer is fixed on an external surface of the aerated concrete substrate. As used herein, the expression 'external surface' refers to a H:\anh\Interwoven\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -24 surface of the substrate that is exposed to the environment surrounding the substrate. Provided it is an external surface, there is no limitation as to which surface of the substrate the cover layer is fixed. 5 For example, when the aerated concrete substrate is provided in the form of a rectangular cuboid brick or a rectangular panel, an external surface of the substrate may be any one of the six faces of the brick or panel. In some embodiments, the external surface onto which the cover layer is fixed is a major 10 external surface of the substrate. As used herein, the expression 'major external surface' refers to an external surface of the substrate having a surface area greater than that of any other external surface of the substrate. Thus, when the aerated concrete substrate is provided in the form of a rectangular cuboid brick or a rectangular panel, a major external surface would be one of the faces of the brick or panel having the largest surface area. 15 In some embodiments, the cover layer is fixed on at least two external surfaces of the substrate. In these embodiments the at least two external surfaces may be at least two adjacent external surfaces. In this case the modules of the invention may be used, for example, in the construction of corner elements, beam elements, pillar elements, stair 20 elements, etc. Alternatively, the at least two external surfaces may be at least two non adjacent external surfaces. In this case the module of the invention may be used, for example, in the construction of partition walls, lintels, or ceiling/floor structures. In a particular case, the cover layer is fixed to opposite external surfaces of the substrate. 25 The expression 'opposite external surfaces' is used herein to indicate non-adjacent external surfaces of the substrate that face diametrically opposite directions. For example, when the aerated concrete substrate is provided in the form of a rectangular panel the cover layer may be fixed to both the major faces of the panel. In this case the resulting module may be used in the construction of partition walls or ceiling/floor structures. 30 H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 -25 In the context of the invention it will be understood that there is not necessarily correspondence between the total area of the external surface to which the cover layer is fixed and the actual extension of the area covered by the layer. For example, once fixed to an external surface of the substrate, the cover layer may cover only a fraction of the area of 5 that surface. In other words, the cover layer may be fixed to an external surface of the substrate such that it does not cover the entire area of the external surface. On the other hand, the cover layer may be fixed to an external surface of the substrate such that it does extend beyond an edge of the surface. 10 Figures 1-4 show schematic representations of embodiment building modules according to the invention. Figure 1(a) shows a building module 10 in which an aerated concrete substrate 11 is provided in the form of a rectangular cuboid brick. Cover layer 12 is fixed on an external 15 surface of the substrate. Figure 1(b) shows a building module 10 in which the aerated concrete substrate 11 is provided in the form of a rectangular cuboid brick, and two cover layers 12 are fixed on opposite external surfaces of the substrate 11. Figure 1(c) shows a building module 10 in which the aerated concrete substrate 11 is provided in the form of a rectangular cuboid brick, and two cover layers 12 are fixed on adjacent external surfaces of 20 the substrate 11. Similarly, Figure 1(d) shows a building module 10 in which the aerated concrete substrate 11 is provided in the form of a rectangular cuboid brick, and two cover layers 12 are fixed on external surfaces of the substrate 11 that are adjacent along a different direction relative to the module shown in Figure 1(c). 25 Figures 2(a) and 2(b) show a building module 20 in which aerated concrete substrate 21 is provided in the form of a rectangular panel. In Figure 2(a) one cover layer 22 is fixed to an external surface of substrate 21, and specifically to a major external surface of substrate 21. In this configuration building module 20 may be used in the construction of a wall, for example an external wall. In Figure 2(b) two cover layers 22 are fixed on opposite external 30 surfaces of substrate 21. In this configuration building module 20 may be used in the H:\anh\Interwoven\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 26 construction of a wall bearing a cover layer on both sides, for example an internal wall or a partition wall. Figure 3 shows a building module 30 in which aerated concrete substrate 31 is provided in 5 the form of a rectangular panel that can be useful for the construction of floor structures. In module 30, cover layer 32 is fixed on the upper major external surface of substrate 31. Figures 4(a), 4(b) and 4(c) show a building module 40 in which aerated concrete substrate 41 is provided in the form of an L-block. In the module of Figure 4(a) cover layers 42 are 10 fixed on the external surfaces of the substrate 41 that form the concave surface portion of the L shape. In Figure 4(b) cover layers 42 are fixed on the external surfaces of substrate 41 that form the convex surface portion of the L shape. In Figure 4(c) cover layers 42 are fixed on the external surfaces of substrate 41 that form both the concave and convex portions of the L shape. In the configurations shown in Figures 4(a)-(c) building module 40 15 can be useful for the construction of corner wall or ceiling elements, either internal or external. In some embodiments, an external surface of the aerated concrete substrate of a module has a groove and/or a protrusion that can accept a corresponding protrusion and/or groove 20 located on an external surface of the substrate of another module. This facilitates the relative positioning and inter-engagement of a plurality of modules in the construction of a building structure. Embodiment modules of this kind are depicted in Figure 5. Figure 5 shows a schematic of two inter-engaging modules 51 and 52. Each module has a 25 substrate 53 or 54 that (i) is in the form of a panel and (ii) has a groove 57 and a protrusion 58 on opposing side surfaces to facilitate mutual inter-engagement of the modules 51 and 52. Figure 5(a) shows inter-engaging modules 51 and 52 each having a cover layer 55 or 56 on one major external surface. Figure 5(b) shows inter-engaging modules 51 and 52 each having a cover layer 55 or 56 on both major external surfaces. 30 H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 -27 In some embodiments, the building module of the invention is load-bearing. By the building module being 'load bearing' is meant that when used in the construction of an edifice the building module of the invention can support a load deriving from overlying parts of the edifice without mechanically failing (e.g. cracking). This will be understood as 5 opposed to a 'non-load bearing' module, which does not support vertical loads except that of its own weight and merely defines spaces. In the context of the invention the load-bearing characteristics of a building module are quantified in terms of compressive strength as determined according to the procedure 10 described in IS: 3495-Part 1-1992, or in terms of flexural compressive strength as determined according to the procedure described in Dayaratnam P, "Brick and Reiforced Brick Structures", Oxford IBH Publishing Co. Pvt. Ltd., New Delhi, India,1987. Accordingly, in some embodiments the load-bearing module of the invention has a 15 compressive strength of between about 1.5 MPa to about 6 MPa, of between about 2 MPa to about 6 MPa, of between about 2.5 MPa to about 6 MPa, of between about 3 MPa to about 6 MPa, of between about 3.5 MPa to about 6 MPa, of between about 4 MPa to about 6 MPa, of between about 4.5 MPa to about 6 MPa, of between about 5 MPa to about 6 MPa, or of between about 5.5 MPa to about 6 MPa. 20 In other embodiments, the flexural compressive strength of the load-bearing module of the invention is between about 0.1 MPa to 2 MPa, between about 0.25 MPa to 2 MPa, between about 0.5 MPa to 2 MPa, between about 0.75 MPa to 2 MPa, between about 1 MPa to 2 MPa, between about 1.25 MPa to 2 MPa, between about 1.5 MPa to 2 MPa, or between 25 about 1.75 MPa to 2 MPa. When additional load bearing capacity is required, the aerated concrete may be internally reinforced. A skilled person would be aware of appropriate reinforcement means suitable for increasing the load bearing capacity of the building modules of the invention. Example 30 of suitable reinforcement means include steel rods, steel mesh, ceramic particles (e.g. zeolite particles), fibres (e.g. glass fibres), or fibre-glass mesh. The reinforcement means H:\anh\Interwoven\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 28 are typically incorporated within the aerated concrete volume in the pre-curing production stage. Building modules in which the aerated concrete substrate is reinforced are useful in the construction of load-bearing building elements in which enhanced tensile resistance is required, for example in floor and ceiling structures, load bearing beams, lintels and stair 5 treads. Advantageously, building modules having a reinforced aerated concrete substrate have improved structural adequacy during installation and design life relative to conventional building materials. In preferred embodiments, the module of the invention is in a configuration selected from 10 any of those shown in Figures 1-5, in which the cover layer is gypsum board. In a particularly preferred embodiment the module has an aerated concrete substrate in the form of a panel of the kind described herein, and a gypsum board cover layer fixed on one or both the major surfaces of the panel. 15 According to the present invention there is also provided a method of making a prefabricated self-supporting building module, the module comprising an aerated concrete substrate and a cover layer, and the method comprising fixing the cover layer to an external surface of the substrate. 20 Provided that fixing the cover layer to an external surface of the substrate results in no relative movement between the cover layer and the substrate, there is no limitation as to how the fixing is performed. Those skilled in the art would be aware of suitable methods and techniques for fixing the cover layer on an external surface of the aerated concrete substrate. For example, the cover layer may be fixed on an external surface of the substrate 25 by way of an adhesive as described herein, or by way of mechanical fastening elements as described herein. Once it is manufactured, the building module of the invention may be provided and transported in a form that is suitable to minimise any damage to its integrity. A skilled 30 person would be aware of appropriate protection system and methods to minimise damage to the module from its production until its use in a construction site.

H:\anh\Intrwovn\NRPortbl\DCC\ANH\9910642_I.docx-31/03/2016 - 29 For example, any surface of the module may be coated with a ply membrane immediately after the module is fabricated. The coated modules may then be stacked in a manner that minimises damage during transportation, yet maximises ease of removal of each module 5 from the stack. For example, suitable separators may be used to provide a separation gap between stacked modules. The ply membrane may be such that is can easily be removed once the module is to be used in the construction site. For example, the membrane may be removed before the construction of the building structure or after said structure is constructed. In the latter case damage resulting from handling the module in the 10 construction of the building structure would be also minimised. Every formulation or combination of components described or exemplified can be used to practice the invention, unless otherwise stated. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same 15 compounds differently. Throughout this specification and the claims which follow, unless the context requires otherwise, the word 'comprise', and variations such as 'comprises' and 'comprising', will be understood to imply the inclusion of a stated integer or step or group of integers or steps 20 but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived 25 from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. A prefabricated self-supporting building module, comprising a monolithic aerated concrete substrate and a cover layer, wherein the cover layer is fixed to an external surface 5 of the substrate.

2. The building module according to claim 1, wherein the aerated concrete substrate is provided in the form of a brick, panel, beam, column, lintel, U-block or L-block. 10

3. The building module according to claim 1 or 2, wherein the external surface is a major external surface of the substrate.

4. The building module according to any one of claims 1 to 3, wherein the cover layer is fixed to opposite external surfaces of the substrate. 15

5. The building module according to any one of claims 1 to 4, wherein the cover layer is fixed by way of an adhesive.

6. The building module according to any one of claims 1 to 4, wherein the cover layer 20 is fixed by way of mechanical fastening elements.

7. The building module according to any one of claims 1 to 6, which is load-bearing.

8. The building module according to any one of claims 1 to 7, wherein the cover layer 25 is fixed to an external surface of the substrate and covers the entire area of the external surface.

9. The building module according to any one of claims 1 to 8, wherein the cover layer is gypsum board. 30 H:\anh\nterwoven\NRPortbl\DCC\ANH\9910642_.docx-31/03/2016 -31

10. Use of a prefabricated self-supporting building module according to any one of claims 1 to 9 in the construction of a building structure.

11. A method of making a prefabricated self-supporting building module, the module 5 comprising an aerated concrete substrate and a cover layer, and the method comprising fixing the cover layer to an external surface of the substrate.