This invention relates to a construction block, particularly a plant-based construction block, and a building element comprising the plant-based construction block.
The construction industry, particularly the cement and concrete industry, is a major contributor to global carbon emissions. Plant-based materials such as wood and crops offer a more sustainable alternative as they capture carbon during growth, which is then trapped in the construction material.
Hemp is known as a material in the construction industry due to its environmental credentials and high performance for thermal insulation.
Hemp insulation products are made of the stalk of the hemp plant, otherwise known as ‘shiv’. The shiv is mixed with a lime-based binder to form a hemp-composite material. The hemp-composite material can be applied to a building structure as a wet mix, akin to render, poured into a cavity, or formed into blocks. Hemp blocks are used to create a thermal insulation layer on the exterior or interior of a wall, and can be finished with render or cladding.
Hemp is advantageous over other insulative materials as it can be quickly and sustainably cultivated, it absorbs carbon as it grows, it is lightweight (a hemp block may be around one eighth of the weight of a concrete block), and it is highly thermal insulating.
Known hemp blocks, for example as available from isohemp®, are used to create an insulative layer on a structural frame. Hemp blocks can be mortared together with an adhesive mortar to form a wall.
The environmental and thermal insulative benefits of hemp make it well suited for improving building thermal insulation in a sustainable manner, and there exists a need for a hemp construction system for new builds and for retrofitting existing buildings.
According to the present invention there is provided a plant-based construction block for a building element, for example a wall, the plant-based construction block comprising a uniform recess extending between two opposite faces of the plant-based construction block, the recess comprising first and second interlocking portions disposed on opposite sides of the recess such that an interlocking portion of a further identical plant-based construction block can be received in the recess and engage the first interlocking portion, and such that an interlocking portion of a second further identical plant-based construction block can be received in the recess and engage the second interlocking portion.
As used herein, the term “plant-based material” means a material derived from plant matter, for example wood or crops such as hemp. The plant-based material may be a plant-composite material, including a plant-derived material and a binder, filler, or other bulk material. The term “plant-based” excludes cementitious construction materials, including concrete.
In examples, the plant-based construction block is generally cuboid and has a top face, a bottom face, opposing side faces, a front face, and a rear face. The recess may extend through the construction block between the top face and the bottom face and opens through the rear face.
The recess may comprise a uniform profile extending between the top face and the bottom face such that the further identical construction block and the second further identical construction block can be slid into the recess.
In this manner, the plant-based construction blocks can be interlocked in a horizontal direction, by interlocking adjacent plant-based construction blocks with the recess, and in a vertical direction, by offsetting interlocking plant-based construction blocks within the recess and adding a further course of plant-based construction blocks. Such vertical and horizontal interlocking improves the structural rigidity of a building element formed by the plant-based construction blocks.
In examples, the first interlocking portion is a mirror image of the second interlocking portion. In particular, the first and second interlocking portions are mirror images of each other about a plane disposed centrally between side faces of the plant-based construction block and extending in the direction of the recess. This allows multiple plant-based construction blocks to be interlocked to form a building element, for example a wall.
In examples, each of the first interlocking portion and the second interlocking portion comprises a male engaging portion and a female engaging portion arranged to receive a corresponding male engaging portion of the further or second further identical plant-based construction block, respectively. Accordingly, when the interlocking portions interlock with an adjacent plant-based construction block they form a double-interlock, with two male engaging portions and two female engaging portions interlocked with each other. This provides high contact surface area between the interlocking portions and improves structural rigidity.
In examples, each male engaging portion and each female engaging portion are rounded. In particular, each male engaging portion may comprise a cylindrical sector and each female engaging portion comprises a tubular passage having a cross-section corresponding to the cylindrical sector of the male engaging portion. Rounded engaging portions ensure that loads are spread across a larger surface area as they are transferred between interlocked plant-based construction blocks. Accordingly, rounded engaging portions reduce stress concentrations in the plant-based material, somewhat mitigating the brittleness of the plant-based material.
In examples, the cylindrical sector of each male engaging portion comprises at least 180 degrees of a cylinder. In particular, the cylindrical sector of each male engaging portion may comprise between about 180 degrees and about 270 degrees of a cylinder.
In examples, each male engaging portion is disposed adjacent to the corresponding female engaging portion such that a wall of the plant-based construction block has an inflection where the male engaging portion joins the female engaging portion. Such an inflection ensures no sharp corner or joint in the wall of the plant-based construction block, reducing stress concentrations further as loads will be transferred across the rounded surfaces of the engaging members.
In other examples, there is a step located between each male engaging portion and each female engaging portion. The step may be substantially parallel to the side faces. The step may provide additional rigidity in the sideways direction when further construction blocks are interlocked in the recess.
In examples, the male engaging members of the first and second interlocking portions are disposed at an exterior mouth of the recess opening through a side of the plant-based construction block, and the female engaging members of the first and second interlocking portions are disposed on an internal side of the recess. Accordingly, the female engaging members are formed at internal corners of the recess.
In examples, each male engaging member extends away from the plant-based construction block, beyond an exterior face (in particular the rear face) of the plant-based construction block.
In examples, the plant-based construction block comprises a hemp-composite material, for example formed of a hemp shiv and a binder. The binder may comprise a lime-based binder or a silica-based binder. The hemp-composite construction block may comprise at least 50% hemp shiv, for example about 75% hemp shiv. The hemp-composite construction block may further comprise an additive or other bulk material.
In other examples, the plant-based construction block may comprise a wood-composite construction block. The wood-composite construction block comprises a wood-composite material. The wood-composite material may comprise a wood derivative material and a binder. The wood-composite material may be formed into a lamella, and a plurality of laminae may be attached to each other to form the wood-composite construction block.
According to a further aspect of the present invention, there is also provided a building element, for example a wall, comprising a first plant-based construction block, a second plant-based construction block and a third plant-based construction block, each of the first, second and third plant-based construction blocks being as described above, and wherein one of the first and second interlocking portions of the second plant-based construction block and one of the first and second interlocking portions of the third plant-based construction block are both received in the recess of the first plant-based construction block so as to engage the first and second interlocking portions of the first plant-based construction block, respectively.
In examples, the second and/or third plant-based construction block is only partially inserted into the recess of the first plant-based construction block such that the plant-based construction blocks are staggered. In this way, a further course of plant-based construction blocks laid on top of the first plant-based construction block would be vertically interlocked with the second and/or third plant-based construction block. Providing both vertical and horizontal interlocking improves the structural rigidity of the building element.
In examples, the building element further comprises a foundation supporting the first, second, and third plant-based construction blocks, and wherein the foundation is staggered such that the second and/or third plant-based construction block is only partially inserted into the recess of the first plant-based construction block. The foundation may comprise a slot to receive the first plant-based construction block. The slot may be shaped to interlock with the first plant-based construction block.
In examples, the foundation further comprises an attachment for a tubular support rod arranged to extend through at least one of the first, second and third plant-based construction blocks. The attachment may comprise a spigot moulded within the foundation or attached thereto. The foundation may comprise a foundation block shaped to match the first plant-based construction block, the foundation block being fixed to the foundation. The foundation block may be concrete. The attachment for the tubular support rod may be provided on the foundation block.
In examples, the building element further comprises a tubular support rod attachable to the foundation by a threaded connector. The tubular support rod may extend through at least one of the first, second and third plant-based construction blocks. The first, second and third plant-based construction block may comprise a hole to receive the support rod. Alternatively, the first, second and third plant-based construction block may not comprise a male engaging portion, creating a vacant space for the support rod. The support rod preferably extends through multiple courses of plant-based construction blocks to provide structural support to the building element.
In examples, the building element further comprises a capping plate attachable to ends of the support rod opposite to the foundation, with the plant-based construction blocks disposed between the foundation and the capping plate. The capping plate may be clamped against the plant-based construction blocks so as to tension the support rods and compress the plant-based construction blocks. Tensioning nuts may attach to the ends of the support rods to clamp the capping plate. By tensioning the support rods the structural rigidity provided by the support rods is increased.
In examples, the building element may further comprise a plurality of load-bearing construction blocks. The load-bearing construction blocks may be shaped to interlock with the at least one of the first, second and third plant-based construction blocks. For example, the load-bearing construction blocks may have the same shape as the first, second, and third plant-based construction blocks. In examples, the load-bearing construction blocks are arranged to provide a load bearing sub-structure of the building element. For example, the load-bearing construction blocks may be interlinked to form a tie line or diagonal that ties two parts of the building element together. In some examples, the tie line may extend between a corner and a support rod of the building element. The load-bearing construction blocks may comprise concrete, polymer or wood-composite material, and may be plant-based or non-plant-based. Providing load-bearing construction blocks may create a load-bearing sub-structure, and plant-based construction blocks may be used to complete the building element.
In examples, the load-bearing construction blocks comprise side interlocking portions formed of a protrusion in a first side face and a recess in an opposite side face of the load-bearing construction block. In examples, the recess extends from a bottom face of the load-bearing construction block partially to the top face, through the first side face. The protrusion extends from the top face of the load-bearing construction block partially to the bottom face, out of the opposing side face. In this way, when two of the load-bearing construction blocks are arranged in a diagonal arrangement they will interlock. This allows the load-bearing construction blocks to be provided only on the inner or outer layer of the building element and still provide a load-bearing path forming a diagonal tie-line. The other of the inner or outer layer of the building element can be provided with plant-based construction blocks, for example to provide thermal insulation.
In examples, the building element comprises a corner. The corner may be formed from corner construction blocks arranged on top of each other and shaped to interlock with plant-based construction blocks extending perpendicularly from the corner construction block. The corner construction blocks may be concrete, polymer or wood-composite. The corner may be load-bearing.
In examples, the building element may comprise a wall, for example an external or internal wall of a building.
In other examples, the building element may comprise an outer skin attachable to an existing wall of a building. The building element may be a retrofittable insulation system. For example, the building element may further comprise a plurality of mounting brackets attachable to the existing wall, and a plurality of support rods attachable to the brackets. At least one of the first, second and third plant-based construction blocks may be configured to be coupled to at least one of the plurality of support rods. The support rods thereby act to attach the plant-based construction blocks to the existing wall. The support rods may be configured to space the plant-based construction blocks from the existing wall, although the space is not necessary as the thermal insulation provided by the plant-based construction blocks is not dependent on there being an intermediate cavity.
In examples, the building element may further comprise a bracket arranged to be retained between the first and second plant-based construction blocks and to provide a mounting point for a cladding system, for example a rail of a cladding system. The bracket may extend past the first and second plant-based construction blocks. In examples, the building element further comprises a cladding system attached to the bracket.
Aspects of the present invention are described hereinafter with reference to the accompanying drawings, in which:
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As illustrated, the recess 3 is extends through the construction block 2, between the top face 5 and the bottom face. The recess 3 opens through the rear face 7. The recess 3 has a substantially uniform cross-sectional form.
The first and second interlocking portions 4a, 4b comprise first and second female engaging portions 10a, 10b, respectively. The first and second female engaging portions 10a, 10b are disposed on an interior side of the recess 3 that is spaced from the rear face 7 towards the front face 6.
The first and second interlocking portions 4a, 4b also comprise first and second male engaging portions 11a, 11b, respectively, that are located on opposing sides of the opening of the recess 3 through the rear face 7.
As illustrated, the first and second male engaging portions 11a, 11b are rounded. In particular, the first and second male engaging portions 11a, 11b comprise a cylindrical sector. In this example, each cylindrical sector comprises approximately 270 degrees of a cylinder. The remaining circumference of the cylinder is joined to the body of the construction block 2. As shown, the first and second male engaging portions 11a, 11b extend beyond the rear face 7 of the construction block 2.
As illustrated, the first and second female engaging portions 10a, 10b are shaped to match the first and second male engaging portions 11a, 11b. That is, each female engaging portion 10a, 10b is rounded. In particular, each female engaging portion 10a, 10b comprises a tubular passage having a cylindrical part that matches the cylindrical sector of the first and second male engaging portions 11a, 11b.
The rounded form of the male engaging portions 11a, 11b and female engaging portions 10a, 10b provides for large contact surface area between the interlocking portions 4 of adjacent construction blocks 2 and reduces stress concentrations under side or shear loads. The rounded form reduces stress concentrations within the constriction block 2. Accordingly, the shape of the interlocking portions 4, particularly the rounded form of the male engaging portions 11a, 11b and female engaging portions 10a, 10b, mitigates the brittleness and lack of hardness of the plant-based material forming the construction block 2.
The cross-sectional form of the construction block 2 is symmetrical about a plane 12 extending through the construction block 2 equidistant from the side faces 8, 9 and in the direction of the recess 3. Accordingly, the first and second interlocking features 4a, 4b are equally spaced from the first side 8 and second side 9, respectively. This allows a plurality of identical construction blocks 2 to be interlocked in a horizontal direction.
As illustrated, the front face 6, side faces 8, 9 and top face 5 are planar, and so is the bottom face. Accordingly, each construction block 2 has five planar faces, and the recess 3 and interlocking portions 4a, 4b are arranged at the rear face 7. In this way, when a plurality of construction blocks 2 are assembled into a front portion and rear portion, as shown in
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The construction blocks 2 described above are plant-based construction blocks 2 formed of a majority plant-derived material and a binder. For example, the plant-derived construction blocks 2 may be hemp-composite construction blocks 2 comprising a hemp material, in particular a hemp shiv, which is made from the stalk of the hemp plant, and a binder. The binder may be lime-based or silica-based. The hemp shiv is cut into an aggregate material and then mixed with the binder then, as described further below, formed into the hemp-composite construction blocks 2. The binder dries or cures to solidify the hemp-composite construction blocks 2. The hemp-composite construction blocks 2 may comprise at least 50% shiv, for example about 75% shiv. The remainder may be binder (e.g., at most 50% or 25%, respectively), or may comprise a binder and other additive or bulk material. In other examples, the plant-based construction blocks 2 may comprise other plant cellulose material and a binder. Examples of plant cellulose material includes, for example, sugar cane, rye, wheat straw, kenaf, or sisal. The source of the plant-based material may be selected based on the location of the building so as to provide a local material source. Different plants are cultivated in different areas, so the choice of plant material may be based on local availability. The binder works in the same way to dry or cure to solidify the plant-based construction blocks 2.
In some examples, the plant-based construction blocks 2 comprise a wood material, for example a wood-composite material. The wood-composite material may comprise a bonded derivative wood material. As shown in
In examples, each construction block 2 may have a length, between the side faces 8, 9, or between about 30 centimetres and about 100 centimetres, for example about 50 centimetres. In examples, each construction block 2 may have a depth, between the front face 6 and the rear face 7, of between about 10 centimetres and about 30 centimetres, for example about 20 centimetres. The combined depth of two interlocked construction blocks 2, between the front faces 6 of the two construction blocks 2, may be between about 25 centimetres and about 50 centimetres, for example about 30 centimetres. The height of each construction block 2, between the top face 5 and the bottom face, may be between about 10 centimetres and about 50 centimetres, for example about 30 centimetres.
In some examples, the building element 1 formed from the plant-based construction blocks 2 may be a load-bearing building element, for example a wall of a building. The interlocking between the construction blocks 2, as described above, means that the structural rigidity of the building element 1 is greater than the sum of the structural rigidities of the individual construction blocks 2, meaning that the building element 1 may be somewhat load-bearing.
Alternatively, as also described hereinafter, the building element 1 formed from the construction blocks 2 may be an internal or external wall insulation system, where the construction blocks 2 are arranged on a surface of an existing building element (e.g., wall) to improve thermal efficiency. In such examples the building element 1 may not be load-bearing other than to bear its own weight.
The building element 2 may be a new-build building element or a retrofit building element.
As described in further examples hereinafter, the building element 1 may comprise plant-based construction blocks 2 and other construction blocks, for example concrete or polymer construction blocks. The other construction blocks may have the same shape as the plant-based construction blocks 2 and may be provided within the building element 1 to provide structural rigidity and/or load bearing paths through the building element 1. Additionally or alternatively, the building element 1 may comprise different types of plant-based construction blocks 2. For example, the wood-composite construction blocks of
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In an alternative example, the load-bearing construction blocks 20 may not have the recesses 72 and protrusions 73 and instead additional load-bearing construction blocks 20 may be provided in the opposite orientation, on the other (inner or outer) portion, to provide a load-bearing path between the load-bearing construction blocks 20a-20c illustrated and thereby provide a load-bearing diagonal tie line 28.
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In other examples, one or more construction blocks may not comprise one of the male engaging portions 11a, 11b illustrated in
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In examples, the support rods 23 are provided by a rod or tube that extends through the building element 1 as described above. In other examples, the support rods 23 may be formed by pouring a hardening material, for example concrete or epoxy resin, into holes formed through the building element 1. The holes may be provided by a tube, for example a plastics tube, that extends through the building element 1.
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In this way, a new build structure can be provided from the plant-based construction blocks 2, load-bearing construction blocks 20, and other features described above. The corners 17, load-bearing construction blocks 20, and/or support rod structure 22, as described above, can provide a structure and the non-load-bearing plant-based construction blocks 2 are interlocked with that structure to complete the building element 1.
In the example of
A further insulating buffer 38b may be provided between the first interlocking portion 4a and the second and third interlocking portions 4b, 4c. The further insulating buffer 38b acts to thermally isolate the two parts of the first building element 1a on either side of the joint block 39. The further insulating buffer 38b may be a thermally insulating plate bolted between two parts of the joint block 39.
The joint block 39 may be made from concrete, polymer, or wood composite material.
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The retrofittable building element 1 may include a foundation 14 as previously described. The support rods 42 may connect to the foundation 14 as previously described.
Construction blocks, in particular plant-based construction blocks 2 and optionally concrete or polymer or wood-composite construction blocks 18, can be assembled in an interlocking manner on the support rods 42 to form an outer layer on the building 40. In this way, a retrofittable external wall insulation system is provided.
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As mentioned above, the plant-based construction blocks comprise a majority plant-derived material and a binder. In particular, the plant-based construction blocks comprise plant cellulose material (e.g., hemp shiv) and a binder, for example a lime-based or silica-based binder. The plant cellulose material and binder are initially mixed to form a wet mix. The wet mix may comprise at least 50% plant cellulose material, for example about 75% plant cellulose material. The remainder of the wet mix (i.e., at most 50%, for example about 25%) may be the binder. The wet mix may additionally comprise a bulk material or other additive.
Once the materials are mixed, the wet mix is transferred to the block manufacturing system 54 as shown in
As illustrated, the compressing plate 56 may be pivoted out of the way to allow the wet mix to be added to the mould 55, and then pivoted such that the compressing plate 56 engages the mould 55. The compressing plate 56 may extend into the mould 55 and be shaped to correspond to the mould form.
Once compressed, the plant-based construction block can be removed from the mould by moving a base plate 58 of the mould 55 and using the compressing plate 56 and actuator 57 to push the plant-based construction block through the opposite side of the mould 55.
The same mould 66 may be used to cast concrete or polymer construction blocks 20.
In some examples, compression of the wet mix may be sufficient to unify the wet mix into the plant-based construction block and the plant-based construction block can be removed and the binder allowed to cure. In other examples, the mould 55 may be heated to speed up the binder curing process. In other examples, the plant-based construction blocks may be heated, for example in a kiln or by a heated air flow, after being removed from the mould.
As shown, a height-adjustable platform 60 is provided with a conveyor system 61 for moving pallets 62 of construction blocks 2, 20 along the platform 60. An operator 63 uses a hoist 64 to lift construction blocks 2, 20 from the pallet 62 and then lower them onto the building element 1 such that the construction blocks 2, 20 interlock with construction blocks 2, 20 already on the building element 1. If a support rod structure is used then the construction blocks 2, 20 can be lowered over the support rods. Alternatively, the support rods can be positioned after positioning the construction blocks 2, 20 by feeding the support rods through the openings in the construction blocks 2, 20. The height-adjustable platform 60 increments up as the building element 1 is constructed. A forklift or other machine can be used to lift more pallets 62 of construction blocks 2, 20 onto the height-adjustable platform 60 as required.
The assembly system 59 provides a safe and efficient method of construction. As no mortar or adhesive is used to bind the construction blocks 2, 20, the building site can be clean and safe from potentially hazardous chemicals.
Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Number | Date | Country | Kind |
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2200056.6 | Jan 2022 | GB | national |
Filing Document | Filing Date | Country | Kind |
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PCT/GB2023/050006 | 1/4/2023 | WO |