GB2623457A

GB2623457A - Construction block and building system

Info

Publication number: GB2623457A
Application number: GB2400698.3A
Authority: GB
Inventors: Mateparae Mapihi
Original assignee: Bossit Online Ltd
Current assignee: Bossit Online Ltd
Priority date: 2024-01-18
Filing date: 2024-01-18
Publication date: 2024-04-17
Also published as: GB202400698D0

Abstract

The present invention provides a construction block able to be assembled into walls and like structures of a building. A wall constructed from the construction blocks comprises a plurality of courses of the blocks arranged one upon another. The construction block comprises a moulded hollow polymer body which may comprise recycled polymer and which has having top and bottom faces, first and second upright end faces, an upright front face and an upright rear face. The first end face is provided with at least one male location feature receivable by a complementary female feature of the second end face of another similarly formed block, whereby in the wall the construction block is able locate with respect to neighbouring construction blocks in the same course, One of the top and bottom faces is provided with at least one male location feature receivable by a complementary female location feature of the other of the top and bottom faces of another similarly formed block, whereby in the wall the construction block is able to locate with respect to neighbouring construction blocks in the courses above it and below it. The front face carries a front facing which may contribute fire resistance.

Description

CONSTRUCTION BLOCK AND BUILDING SYSTEM

The present invention relates to construction blocks comprising polymer material, for use in the construction industry.

The use of blocks in some form in construction of buildings has a very long history, with sun-dried mud blocks thought to have been used as long ago as 7000 BCE. In the modern construction industry, blocks come in a variety of forms and are made in a range of materials including clay, concrete, aggregate and so on.

Polymer materials have a number of attractions for construction blocks. One of these relates to the preservation of the environment. Polymer waste is generated on a huge scale globally, representing a wastage of the energy and raw materials invested but also a major global challenge in terms of ecologically acceptable disposal, and the pollution that results from inappropriate disposal. If a portion of this polymer waste could be repurposed in the construction industry, significant global environmental benefits would result.

Polymer materials are also attractive in that they can be quickly and accurately moulded, facilitating mass block manufacture. The energy requirement in moulding polymers is modest. Suitably treated they can have a long working life. Polymers lend themselves to formation of fine features of shape, so that polymer construction blocks may be shaped to locate upon one another accurately, reducing the level of skill needed in their deployment compared, for example, with the laying of house bricks or concrete construction blocks separated by courses of lime or concrete-based mortar.

But there are significant obstacles to widespread adoption of polymer-based construction blocks. One of these is fire safety. Polymer materials can lose their structural integrity at relatively modest temperatures, compared to more established construction materials such as concrete. The fumes released when polymers burn can be toxic and can be more harmful than the fire itself. A solution is needed to these problems to enable the widespread adoption of polymers for construction blocks, and preferably it should be one that does not complicate the manner of construction using the blocks.

Other challenges include (a) providing an appropriate means for one block to locate with respect to its neighbours, (b) coupling polymer blocks together in a wall, given that conventional mortar joints are not appropriate, (c) thermal insulation properties of a polymer block, since energy efficiency of a building is a key performance issue in the modern construction industry, (d) providing an appropriate process for manufacture of a polymer block, capable of production on a large scale, and (e) providing for routing of utilities including electrical cabling and conduits for mains and waste water.

US769448581, Siener, discloses a mortarless interlocking building block which is moulded in plastic and has wedge-shaped projections receivable in complementary tapered sockets to lock each block to its neighbours. No means of protecting the resultant plastic structure from destruction by heat or flame is apparent from the document.

EP2619378, Pigeon Enterprises, discloses a construction block made of concrete cast onto a framework of injection-moulded polystyrene, said to have advantageous thermal properties. It seems apparent that the substantial cast-in-situ concrete facings provide structural integrity.

According to a first aspect of the present invention, there is a construction block configured to be assembled to other such blocks to form a wall comprising a plurality of courses of the blocks arranged one upon another, the construction block comprising a moulded hollow polymer body having top and bottom faces separated by a block depth, first and second upright end faces, an upright front face and an upright rear face, wherein: the first end face is provided with at least one male location feature receivable by a complementary female feature of the second end face of another similarly formed block, whereby in the wall the block is able to be located with respect to neighbouring blocks in the same course, one of the top and bottom faces is provided with at least one male location feature receivable by a complementary female location feature of the other of the top and bottom faces of another similarly formed block, whereby in the wall the block is able to be located with respect to neighbouring blocks in the courses above it and below it; the front face carries a front facing having upper and lower edges separated by a front facing depth; wherein the block depth is greater than the front facing depth, so that in the wall the upper edges of the front facings in one course are separated by a clearance from the lower edges of the front facings in the course above, and so that that compressive loads are carried by the polymer bodies of the construction blocks and not by the front facings.

In a wall formed of such construction blocks, the facings together provide a fire-resistant shield for the structural elements -the interlocking hollow polymer bodies. The clearance between the facings ensures that the facings themselves are not subject to loading which might cause them damage and/or tend to detach them, in a manner that could impair fire safety.

According to a second aspect of the present invention, there is a construction block configured to be assembled to other such construction blocks to form a wall comprising a plurality of courses of the construction blocks arranged one upon another, the construction block comprising a moulded hollow polymer body having top and bottom walls, first and second upright end walls, an upright front wall and an upright rear wall, wherein: the front wall carries a front facing; the rear wall carries a rear facing; the first end face is provided with at least one male location feature receivable by a complementary female feature of the second end face of another similarly formed construction block, whereby in the wall the construction block is able to be located with respect to neighbouring construction blocks in the same course, the polymer body further comprises an internal wall extending between the top wall and the bottom wall and defining a coupling chamber which is upwardly open through an upper opening in the top wall and is downwardly open through a lower opening in the bottom wall, a rim, upstanding from the top wall extends around the upper opening, a rebate in the bottom wall extends around the lower opening, so that in the wall, the rim of the construction block in a first course is receivable by the rebate of another, similarly formed, construction block in a course immediately above, whereby in the wall the block is able to be located with respect to neighbouring blocks in the courses above it and below it, the construction block being configured such that the coupling chambers of the construction blocks align between one course and the next, forming coupling columns able to receive tie bars to secure the wall together, in which the rims of the construction blocks form a barrier to entry of water to the coupling columns.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-Figure 1 depicts a construction block according to the present invention, viewed from above and to one side; Figure 2 depicts the construction block of Figure 1, viewed from beneath and to one side; Figure 3 depicts the construction block inverted and cut through in a horizontal plane to reveal internal detail; Figure 4 depicts the construction block of Figure 1, viewed from below; Figure 5 depicts the construction block of Figure 1, viewed from above; Figure 6 depicts the construction block of Figure 1, viewed from one end; Figure 7 depicts the construction block of Figure 1, viewed from above and somewhat simplified; Figure 8 is a section through the construction block of Figure 1 in the longitudinal plane A indicated in Figure 7; Figure 9 is a section through the construction block of Figure 1 in the longitudinal plane B indicated in Figure 7; Figure 10 is a section through the construction block of Figure 1 in the lateral plane C indicated in Figure 7; Figure 11 is a section through the construction block of Figure 1 in the lateral plane D indicated in Figure]; Figure 12 is a perspective depiction of the construction block of Figure 1, viewed from above and to the rear; Figure 13 depicts part of a wall, constructed using the construction blocks, upon a foundation; Figure 14 depicts a cast-in panel used in embodiments of the present invention, viewed from above and one side; Figure 15 depicts the cast-in panel viewed from one side; Figure 16 depicts a pipe installation in a wall constructed according to the present invention; Figure 17 is a further depiction of the pipe installation; Figure 18 depicts a stage in the construction of a beam above a wall opening, in accordance with the present invention; Figures 19 to 22 depict successive stages in the laying of a concrete slab floor using a construction system embodying the present invention; Figure 23 depicts built-in formwork used in the laying of said concrete slab floor; Figure 24 depicts a corner block used in a building system embodying the present invention, viewed from above and to one side; Figure 25 depicts the corner block of Figure 24, viewed from beneath and to one side; Figure 26 depicts a further corner block used in the building system according to the present invention; Figure 27 is a schematic representation of an arrangement used to couple facings to a polymer body in the construction block of Figure 1; Figure 28 depicts a lintel block used in the building system according to the present invention, viewed from above and to one side; and Figure 29 depicts the lintel block of Figure 28, viewed from below and to one side.

Construction block 10 is parallelepipedal in shape, and more specifically in the present embodiment it is a rectangular cuboid, having a bottom face 12, a top face 14, first and second end faces 16a, 16b, a front face 18 and a rear face 20. The structural element of the construction block 10 is a hollow body 22 comprising polymer material. At the front face of the construction block 10, a fire-resistant front facing 24 is secured to the hollow body 22. At the rear of the hollow body 22, a fire-resistant rear facing 26 is secured to the hollow body 22.

The construction block 10 forms the basis of a building system in which many such blocks are assembled to one another to form walls and other structures. The building system other standardised components as will be explained below. Faces of the construction block 10 are shaped to locate with respect to the adjacent faces of similarly formed neighbouring blocks, making the process of laying the blocks a straightforward one since misalignment of one block with respect to its neighbours is prevented.

In this construction system, the hollow polymer bodies 22 form the wall's structure and it is these parts that give the wall its rigidity and that sustain compression load due to weight. The front and rear facings 24, 26 form a fire-resistant layer over the inside and the outside of the walls, protecting the hollow bodies 22 from degradation by excessive heat, especially in the event of a fire.

The hollow body 22 takes the form of a cuboidal box having a bottom wall 30, a top wall 32, end walls 34a, 34b, a front wall 36 and a rear wall 38. Upright internal walls 40, 42 form chambers 44, 46 extending through the hollow body 22 from bottom to top, these chambers being open through both the bottom wall 30 and the top wall 32. In the example depicted in the Figures, internal walls 40 form coupling chambers 44, which are of circular section in the present example although other shapes are possible without departing from the scope of the present invention. The coupling chambers are arranged in a straight row at regular spatial intervals along the length of the hollow body 22. The internal walls 42 form utility chambers 46 which are of rectangular section, although again other shapes are possible. The utility chambers 46 are adjacent the rear wall 42, and are arranged in a straight row at regular spatial intervals along the length of the hollow body 22.

In the present embodiment the coupling chambers 44 have an internal diameter sized to enable them to receive a standard waste drain (pipe) including its collars and flanges.

The internal walls 40, 42 extend between the top and bottom walls 32, 30 and contribute to the structural integrity of the construction block 10, especially with regard to the compressive load it is able to sustain.

The end faces 16a, 16b are provided with intra-course location features 50, 52 through which, when the construction blocks 10 are assembled in a wall, the end face 16a of one construction block 10 locates with respect to the end face 16b of a similarly formed neighbouring block in the same course, thereby helping to ensure proper alignment. The intra-course location features comprise at least one male intra-course location feature 50 on one end face 16a, and at least one complementary female intra-course location feature 52 on the other end face 16b. In the present embodiment the male intracourse location feature 50 takes the form of a tongue upstanding from the end face 16a and running vertically from the bottom of the hollow body 22 to the top. The female intra-course location feature 52 takes the form of a complementary groove formed in the end face 16b and extending vertically from the bottom of the hollow body 22 to the top. This formation of the intra-course location features 50, 52 serves also to provide protection against ingress of water between the end faces 16a, 16b of neighbouring construction blocks 22, especially where some form of sealant, such as non-setting mastic, is applied during assembly. The intra-course location features 50, 52 may take other forms without departing from the scope of the present invention.

The bottom and top faces 12, 14 are provided with inter-course location features 60-70 through which, in a wall, the top face 14 of one construction block locates with the bottom face 12 of one or more similarly formed blocks in the course immediately above it, thereby helping to ensure proper alignment between courses of the construction blocks 10. The inter-course location features comprise at least one male inter-course location feature 60, 62, 64 on one of the bottom and top faces 12, 14 and at least one complementary female inter-course location feature 66, 68, 70 on the other of the bottom and top faces 12, 14. In the present embodiment there are multiple male inter-course location features formed on the top face 14:-a raised coupling-chamber rim 60 extends around the open upper end of each coupling chamber 44; a raised utility-chamber rim 62 extends around the open upper end of each utility chamber 46; and a raised tongue 64 extends along the length of the top face 12 and there are multiple complementary female features formed on the bottom face 12:-a coupling-chamber rebate 66 (in US English, a rabbet) is formed around the lower end of each coupling chamber 44 to receive a coupling-chamber rim 60 of the construction block 10 beneath; a utility-chamber rebate 68 is formed around the lower end of each utility chamber 46 to receive a utility-chamber rim 62 of the construction block 10 beneath; and a groove 70 extends along the length of the bottom face 14 to receive the tongue 64 of a construction block 10 beneath.

As well as providing positive location of one construction block 10 with respect to those above and below it in a wall, the inter-course location features 60-70 provide protection against ingress of water, especially when a suitable sealant is applied during assembly. The tongue 64 and groove 70 together form a labyrinthine barrier to water ingress between the top and bottom block faces 14, 12. The raised coupling-chamber prevents water from flowing into the coupling chamber 44. The raised utility-chamber rim 62 prevents water from flowing into the utility chamber 46. The inter-course location features 60-70 may take different forms in other embodiments.

In a wall, the coupling chambers 44 of construction blocks 10 in one course align with those of construction blocks 10 in the course above and in the course below, if present, forming continuous upright coupling columns 72 through the wall structure, as depicted in Figure 13. Likewise, the utility chambers 46 in all courses align, forming continuous upright utility passages 74. Regular and identical spacing of the coupling chambers 44 and of the utility chambers 46, as well as the inter-course location features 60-70, enable the construction blocks 10 in one course to be staggered with respect to those of the courses above and below to form a desired bond pattern, such as the running bond well known in relation to the laying of house bricks.

The front and rear facings 24, 26 of the present embodiment comprise cement board, chosen inter alio for its fire-resistant properties. The cement board comprises fibre-reinforced concrete. Its mode of manufacture is well known in the art. Other fire-resistant materials could be substituted. The facings may comprise a fire-resistant and/or intumescent coating. This may be applied to both faces of the facings, or to only the exposed faces, directed away from the hollow body 22. In the present embodiment the facings 24, 26 are coated in intumescent paint. Suitable paints are known to those skilled in the art.

In Figure 6 it can be seen that the lower edge of the front facing 24 extends a short distance beneath the lower edge of the hollow body 22, forming a depending lip 80. The upper edge 82 of the front facing 24 lies a short distance beneath the top face 14 of the hollow body 22, forming a shallow rebate 84. In a wall, the lips 80 of construction blocks 10 in one course are received by the rebates 82 of construction blocks 10 in the course beneath. This is a water-management feature, helping to ensure that water cascades down the front face of the wall and does not find its way between the top and bottom faces 14, 12 of the construction blocks 10, since to do so it would have to flow upward behind the lip 80. A lower edge 86 of the rebate 84 is inclined to prevent any water from pooling in this region.

In a wall, compression loads are borne by the hollow polymer bodies 22 of the construction blocks 10, not by the front and rear facings 24, 26. To ensure this, depth 88 of the front facing 24 (indicated in Figure 6) and depth 90 of the rear facing 26 are slightly smaller than depth 92 of the hollow body 22. To put the matter another way, in the assembled wall there is clearance between upper edges 94, 82 of the facings of one construction block 10 and the lower edges 98, 100 of the facings of the construction block 10 above it. This clearance can be small. The hollow bodies 22 are thus the key structural elements of the wall.

The hollow body 22 comprises a polymer material, which may be plastic. The material may be a thermoset plastic. It may be fibre reinforced. Glass fibre reinforcement may be used. In principle the fibre reinforcement could be laid up, but for mass manufacture short strand fibre reinforcement is highly suitable. In the present embodiment, the material of the hollow body 22 is high density polyethylene (HDPE) with short-strand fibre reinforcement. Other polymers/plastics may be used. Suitable materials include polyamides, nylon and polybutylene terephthalate ("PBT"). Polyamide 6 ("PA6") can be used. In the present embodiment, the composition of the polymer material also includes a fire-retardant additive, rendering it non-combustible, or at least resistant to combustion.

Halogen-free ammonium polyphosphate may be used. With the fire retardant, the polymer material of the present embodiment is capable of meeting the requirements of the UL94 VU rating released by the Underwriters Laboratories (USA). Other suitable additives are known in the art. The polymer material may be recycled. Recycling of polymers including HDPE is a well-established and widespread practice. By enabling recycling of the polymer into building structures, the present invention offers important environmental benefit.

The interior of the hollow body 22 is packed with an insulating material. The insulating material may itself be recycled. In the present embodiment it comprises textile waste. The combination of the hollow polymer block 22 and the internal insulation provides thermal and acoustic insulation. The textile waste is treated to provide it with fire resistance. This process may comprise spraying.

Part of a wall 108 using the construction blocks 10 is depicted in Figure 13, and has in this example a poured concrete foundation 110 into which is incorporated a cast-in panel 112, depicted in Figures 14 and 15. The cast-in panel 112 may comprise metal, especially steel, and has a tray 114 having an upturned lip 116, which in use forms a barrier to water ingress, along one long edge and a downwardly turned lip 118 along the opposite long edge, giving the cast-in panel 112 rigidity. The cast-in panel 112 is formed to enable construction blocks 10 to seat and locate upon it, having for this purpose first raised location rims 120 about coupling-chamber openings 122, second raised location rims 124 about utility-chamber openings 126, and a raised longitudinal tongue 128. The arrangement of the raised features 120, 124, 128 corresponds to the arrangement of the rebates and grooves 66, 68, 70 on the bottom face of the construction block 10. The cast-in panel 112 thus provides a stable base for the wall 108 and provides positive location of the first course of construction blocks 10 in the wall.

The concrete foundation 110 incorporates steel reinforcement bars 130 which extend horizontally across the foundation 110 but are shaped and arranged to run vertically upward beneath the wall, as seen at 132, emerging from the foundation 110 to pass through the coupling-chamber openings 122 into the coupling columns 72 of the wall. The spacing of the steel reinforcement bars is arranged to match the spacing of the coupling columns 72 of the wall. The effect is to firmly integrate the wall with the foundation.

The reinforcement bars 130 extend upwards through the wall. They may be provided in manageable lengths, e.g. of 1 metre, being threaded or provided with fittings at either end to enable them to be coupled to further, similarly formed, bars. This facilitates laying of the construction blocks 10, avoiding any need to pass them over excessively high reinforcement bars 130. In fact the laying of the construction blocks 10 can be very straightforward, simply involving application of any mastic/sealant to the mating faces and then placing the construction blocks 10 in position, their location features 50, 52, 60-70 ensuring correct positioning and alignment. While Figure 13 shows end faces 16 of the construction blocks 10 aligned with each other across courses, the more usual approach will be to stagger the end faces between courses, forming a bond pattern such as the aforementioned running bond.

The reinforcement bars 130 maintain the construction blocks 10 in engagement with one another, giving the wall the necessary structural integrity without needing to rely on adhesive to secure the construction blocks 10 to one another (although adhesive could be used without departing from the scope of the present invention). The reinforcement bars 130 may for this purpose by maintained in tension through e.g. threaded fittings at their upper ends.

The coupling columns 72 may be filled with settable material such as concrete, encasing the reinforcement bars 130 and further contributing to the structural integrity of the resultant wall 108.

This is not necessary in all applications, however. It may for example be preferable to use selective concrete filling, or to use it in the lower part of a structure or not in the upper part -this will be a matter for determination according to the specific application. Some of the coupling columns 72 will be left without reinforcement bars 130 to house services such as waste pipes and water pipes, and the coupling columns are sized to receive standard-sized services The wall 108 may incorporate lintel blocks 1000 (see especially Figures 28 and 29) which can serve any of several different functions:- 1. they may be arranged in a full course across the wall and provided with internal reinforcement to form a reinforcing beam, or they may be arranged around an entire loop such as the outer walls of a building, again with internal reinforcement, providing a ring beam. Ring beams are important structurally in some buildings, as is well known in the art; 2. they can accommodate and provide access to services, such as water pipes and drains; 3. they may be used, again with reinforcement, as headers above openings such as windows and doorways; 4. they are used at a wall/floor junction, as will be explained.

Figures 28 and 29 depict the lintel block 1000, which is shaped to substitute directly for the construction block 10, having for this purpose coupling-chamber rebates 1066 and utility-chamber rebates 1068 which are formed in a bottom wall 1030 and whose shape and arrangement correspond to those of the rebates 66,68 of the construction block 10, enabling the lintel block 1000 to seat upon a course of the construction blocks 10. The lintel block 10 has a front wall 1036 and a rear wall 1038, these being more substantial than the front and rear walls of the construction block 10 because they are required to carry more load, the lintel block 1000 lacking the internal walls 40, 42 of the construction block 10. The front and rear walls 1036 and 1038 are coupled through the bottom wall 1030 and through sub-walls 1031 adjacent the block's upper edge, but the lintel block 1000 lacks end walls, its end faces instead being open so that a course of the lintel blocks 1000 forms a continuous horizontal passage to receive reinforcement or services such as pipework. The lintel block 1000 has in this embodiment no top wall, instead being upwardly open. Coupling-chamber openings 1067 are provided in the bottom wall 1030. The front wall 1036 has utility-channel openings 1037 arranged to align with the utility chambers 46 of the construction block 10, in a wall. Like the construction block 10, the lintel block 1000 has front and rear fire-resistant facings 1024, 1026.

To form a beam or ring beam, a course of the lintel blocks 1000 is incorporated in the structure and reinforcement such as steel rebar is laid along the course. Concrete can then be poured into the course through the upwardly open faces of the lintel blocks 1000 to form a rigid structure.

A course of lintel blocks forms a continuous horizontal passage, so pipework can be led vertically through one of the coupling columns 72 and horizontally through a course of lintel blocks. In Figure 16, the rear walls 1038 of lintel blocks 1000 are removed, revealing a vertical riser pipe 150 extending upwardly through one of the coupling columns 72 and having horizontal branches 152 running through the passage formed by the lintel blocks 1000. As shown in Figure 17, these branches 152 emerge through holes in rear wall 1038 for onward connection Fire-resistant collars may be fitted to maintain the integrity of the structure's fire protection.

Figure 18 depicts how a header beam is formed above a building opening using the lintel blocks. The bottom edge of the opening is formed by construction blocks 10, with capping 158 upon their upper edge. A capping bar 160 is provided across the top of the opening. A temporary prop 162 is provided to support the capping bar 160, and then lintel blocks 1000 are laid across the opening upon the capping bar 160. Reinforcement such as steel reinforcement bars is laid in the channel formed by the lintel blocks 1000, and may be secured to the capping bar 160 to retain it in position. Pouring concrete into the lintel-bar channel produces a rigid header beam.

The specific form of the header beam in any given case can be determined by a structural engineer and may differ from that described above.

Figures 19 to 22 depict steps in the process of making a poured concrete floor above ground level using the present building system, and Figure 23 depicts formwork 200 incorporated into the wall/floor junction. The structure depicted in Figure 19 has a course of the lintel blocks 1000 forming what is -at this stage of construction -the top of a wall 108. Standing proud of that course and engaging with it through depending walls 202, 204 is the formwork 200. In Figure 20, corrugated floor tray 206 has been introduced and alternate reinforcement bars 130 have been bent through ninety degrees, for incorporation into the concrete floor slab 210. Concrete can then be poured as in Figure 21 to form the slab 210, leaving upper ends 208 of the reinforcement bars 130 to be connected to further bars above them. If the wall is to continue upward then, as in Figure 22, a cast-in plate 112 may be incorporated into the poured slab to locate the next layer of construction blocks 10. The formwork 200 remains in place, forming part of the outer surface of the structure.

The building system lends itself also to the use of timber joists instead of the concrete slab floor of the above example. The joists may for example be fixed to a joining plate secured to the construction blocks 10, or it may sit on top of the construction blocks 10. Such details will typically be determined by a structural engineer and may vary from one installation to another.

The building system includes corner blocks 2000, 2000b in at least two different lengths, depicted in Figures 24, 25 and 26. These are used at external corners of a building. One end face 2016 of each corner block will be exposed and so requires no location features 50,52, which are thus omitted, but this exposed end face carries a facing 2001 to provide continuous fire protection. The different lengths of the two corner blocks 2000a, 2000b allow staggering of the end faces 16 of the construction blocks 10 in alternate courses, in the finished wall.

The construction blocks 10, lintel blocks 1000 and corner blocks 2000 may be provided in other sizes, each having an integral number of the coupling chambers 44.

The building system provides for convenient routing of electrical cabling, for data and for power, by virtue of the aligned utility chambers 46 which form vertical cabling ducts. Sockets may be attached to the rear faces of the construction blocks 10, or they may be let into the blocks.

It is desirable that the facings 24, 26 of the construction block should be securely integrated with the hollow body 22. In the present embodiment, this is achieved by moulding the hollow body 22 in a mould cavity whose front and rear walls are formed by the facings 24, 26 themselves. In this way, intimate engagement of these parts of the construction block 10 is assured. Further, the facings are provided with a mechanical key which, in the finished construction block 10, is embedded in and embraced by the hollow body 22. One form of mechanical key is depicted in Figure 27 and comprises a shaped peg 250 received by the facing 24, 26 and penetrating into the hollow body 22. In this example the peg 250 comprises a frusto-conical head received in a complementary countersunk bore in the facing 24, 26. Several such pegs may be provided at separate locations on the facing 24, 26. In other embodiments the surface of the facing 24, 26 may itself be shaped, e.g. with undercut grooves, to receive the material of the hollow body 22 and mechanically engage with it. The pegs are formed of fibre-reinforced concrete in this example. Other materials may be used. A thermally insulatin material is preferred, to avoid transmission of potentially-damaging heat to the polymer body 22 in the event of fire.

Drugin manufacture of the polymer body 22, it is necessary to provide for mould release, and for introduction of the filler material into the hollow body 22. To this end, in the present embodiment, the bottom wall 30 is a separate moulding from the remainder of the hollow body 22, being secured to it after filling by some suitable means, which may comprise plastic welding or use of an adhesive.

During laying of wall 108, a sealant may be applied to mating faces of the construction blocks 10, the lintel blocks 1000 and the corner blocks 2000. This may take the form a fire-resistant non-sefting mastic. In this way provision is made against passage of air, which would impair thermal performance, and against passage of water Also passage of any accidentally released flammable gas into the wall structure, which might blow a wall apart if inadvertently ignited, is prevented. The use of a non-sefting sealant facilitates reuse of the construction blocks.

The inner surface of wall 108 may receive a coating. This coating may for example comprise flexible plaster. It may fill the aforementioned clearance between rear facings 26, whilst being sufficiently flexible to ensure that comprssion loads are not borne by the facings 26.

While the above-described embodiments use fire resistant facings 24, 26 comprising cement board, any suitable fire-resistant material could be substituted.

A non-combustible UV resistant layer may be applied to exposed surfaces of the facings 24, 26. This may comprise a rubber composition. The front facings 24 provide a substantially flat and continuous outer surface to the wall and could provide its outermost layer, but in many cases a further façade will be applied to the wall, reducing thermal stress suffered by the facings.

While the construction blocks 10 may be made using virgin materials, maximum environmental benefit is obtained by the use of recycled polymer material and recycled filler.

Claims

CLAIMS1. A construction block configured to be assembled to other such blocks to form a wall comprising a plurality of courses of the blocks arranged one upon another, the construction block comprising a moulded hollow polymer body having top and bottom faces separated by a block depth, first and second upright end faces, an upright front face and an upright rear face, wherein: the first end face is provided with at least one male location feature receivable by a complementary female feature of the second end face of another similarly formed construction block, whereby in the wall the construction block is able to locate with respect to neighbouring construction blocks in the same course, one of the top and bottom faces is provided with at least one male location feature receivable by a complementary female location feature of the other of the top and bottom faces of another similarly formed construction block, whereby in the wall the construction block is able to locate with respect to neighbouring construction blocks in the courses above it and below it; the front face carries a front facing having upper and lower edges separated by a front facing depth; wherein the block depth is greater than the front facing depth, so that in the wall the upper edges of the front facings in one course are separated by a clearance from the lower edges of the front facings in the course above, and so that that compressive loads are carried by the polymer bodies of the construction blocks and not by the front facings.
2. A construction block as claimed in claim 1 in which the rear face carries a rear facing having upper and lower edges separated by a rear facing depth, and in which the rear facing depth is smaller than the block depth.
3. A construction block as claimed in claim 1 or claim 2 in which the clearance is less than 2mm.
4. A construction block as claimed in any preceding claim in which the polymer material of the hollow body comprises a fire retardant.
5. A construction block as claimed in claim 2 in which the front and rear facings are fire resistant.
6. A construction block as claimed in any preceding claim in claim 2 in which the front and rear facings are provided with an intumescent coating.
7. A construction block as claimed in any preceding claim in which the front facing extends below a lower edge of the front face, forming a depending lip, and the upper edge of the front facing is below an upper edge of the front face, forming a rebate, so that in the wall the depending lip of a block in one course covers the rebate of a block in the course below, forming an obstacle to ingress of water.
8. A construction block as claimed in any preceding claim in which the hollow polymer body comprises at least one internal wall forming a coupling passage leading from an opening in the bottom face to an opening in the top face, the blocks being configured such that coupling passages in the different courses in the wall align to form a coupling column for receiving an elongate member.
9. A construction block as claimed in claim 8 when dependent on claim 7 in which the internal wall extends from the bottom wall to the top wall.
10. A construction block as claimed in claim 8 or claim 9 in which the location feature of the top face comprises a raised rim about the opening in the top face, providing an obstacle to ingress of water to the coupling column, and in which the location feature of the bottom face comprises a recess about the opening in the lower face to receive and locate upon the raised rim.
11. A construction block as claimed in claim 8 or claim 9 comprising two or more coupling passages.
12. A construction block as claimed in any preceding claim in which the polymer body comprises at least one internal wall defining a utility chamber extending from a utility-chamber opening in the bottom face to a utility-chamber opening in the top face, the blocks being configured such that utility chambers in the different courses in the wall align to form a utility passage for receiving utilities.
13. A construction block as claimed in claim 12 in which the location feature of the top face comprises a raised rim about the utility-chamber opening in the top face, providing an obstacle to ingress of water to the utility passage, and in which the location feature of the bottom face comprises a recess about the opening in the lower face to receive and locate upon the raised rim.
14. A construction block as claimed in any preceding claim in which the male location feature of the first end face comprises a tongue and the female location feature of the second end face comprises a groove for receiving the tongue.
15. A construction block as claimed in claim 14 in which the tongue and the groove extend from an upper edge of the end face to a lower edge of the end face, forming in the wall a barrier to ingress of water between end faces of adjacent construction blocks.
16. A construction block as claimed in any preceding claim in which the top face comprises a male location feature in the form of a tongue and in which the bottom face comprises a female location feature in the form of a groove for receiving the tongue.
17. A construction block as claimed in claim 16 in which the tongue extends from end to end of the top face and the groove extends from end to end of the bottom face, forming in the wall a barrier to ingress of water between top and bottom faces of blocks in adjacent courses.
18. A building system comprising the construction blocks as claimed in any of claims 1 to 17 and a lintel block configured to be built into the wall and comprising: a polymer body having front and rear walls, a front facing on the front wall, a rear facing on the rear wall, a bottom wall provided with location features for locating on the location features of the top wall of the construction block and first and second open end faces at opposite ends of the lintel block so that a course of lintel blocks forms a horizontal channel able to receive reinforcement to form a structural beam.
19. A wall comprising construction blocks as claimed in claim 8 or in any of claims 9 to 17 when dependent on claim 8, in which elongate tension members are provided through at least some of the coupling columns, serving to retain the construction blocks in place.
20. A wall as claimed in claim 19 in which at least some of the coupling columns are at least partly filled with cement-based material around the tension members.
21. A wall as claimed in claim 19 or claim 20 upon a foundation of cement-based material containing reinforcing bars, wherein at least some of the bars extend upwardly out of the foundation and into the coupling columns to form the elongate tension members.
22. A structure comprising a wall as claimed in any of claims 19 to 21 and a concrete slab floor supported by the wall, wherein at least some of the elongate tension members passing through the coupling columns are elbowed, in a region where they emerge from upper ends of the coupling columns, to extend substantially horizontally through the concrete slab floor.
23. A structure as claimed in claim 22 in which built-in formwork is provided about the edge of the concrete slab floor, the formwork engaging with an upper edge of the wall.
24. A method of manufacture of a construction block configured to be assembled to other such blocks to form a wall comprising a plurality of courses of the blocks arranged one upon another, the construction block comprising a moulded hollow polymer body having top and bottom faces, first and second upright end faces, an upright front face and an upright rear face, wherein: the first end face is provided with at least one male location feature receivable by a complementary female feature of the second end face of another similarly formed block, whereby in the wall the block is able to be located with respect to neighbouring blocks in the same course, one of the top and bottom faces is provided with at least one male location feature receivable by a complementary female location feature of the other of the top and bottom faces of another similarly formed block, whereby in the wall the block is able to be located with respect to neighbouring blocks in the courses above it and below it; the front face carries a front facing; and the rear face carries a rear facing; the method comprising forming a mould cavity using the front and rear facings and moulding the hollow polymer body in the mould cavity, so that during moulding the polymer contacts and forms an intimate engagement with the facings.
25. A method of manufacture as claimed in claim 24 which further comprises providing each of the facings with at least one male or female feature to be received or filled by the polymer material during moulding and to provide mechanical engagement between the facing and the hollow polymer body in the finished construction block.