GB2575701A

GB2575701A - A building element

Info

Publication number: GB2575701A
Application number: GB1900666.7A
Authority: GB
Inventors: John Gray Ramon
Original assignee: Zicon Ltd
Current assignee: Zicon Ltd
Priority date: 2019-01-17
Filing date: 2019-01-17
Publication date: 2020-01-22
Anticipated expiration: 2039-01-17
Also published as: US20220074204A1; GB2575701B; SA521422524B1; EP3911804A1; WO2020148519A1; GB201900666D0

Abstract

The building element 20, for the easy construction of a high-strength structure, comprises an insulating core 21 bonded to two outer panels 22 in an offset configuration, providing an overhang 23 over at least one side edge of the core. The opposite edge 24 of the core may be exposed. The insulating block may be formed from polystyrene and the panels from geopolymer concrete. The insulation core may include ridges or profiles 26, 27 for connecting to adjacent blocks. The panels may be attached to the core using adhesive, fastening rods or pins. The core may include at least one bore for receiving a tie bar or fastening rod. Also claimed is a system of building construction consisting of assembling a wall using said building elements. The wall may be compressed using a base beam, capping beam and tie bar.

Description

A building element

The invention relates to an insulated building element, e.g. block or panel, having interconnecting features and, particularly, a system and method of constructing a wall of such blocks/panels. In use the invention provides for simple and fast assembly by unskilled workers from a single component to erect housing or other building structures.

Background to the invention

Across the world the rate of construction for new housing is not sufficient to support population growth. In fact, it is considered one of the major challenges of the twenty-first century. To adequately address the problem housing must be produced more quickly, at lower cost and preferably without environmentally damaging effects, e.g. as is evident from traditional building that includes the production of Ordinary Portland Cement (OPC) and the firing of traditional bricks.

Materials are in short supply, as are the skilled artisans necessary to undertake building projects. Furthermore, there is now a greater understanding of the need for a significantly greener approach to mitigate mankind's effects on the planet. It is estimated that the manufacture of OPC and associated building bricks is responsible for up to 20% of all carbon emissions.

As mentioned, the provision of new housing across the world is falling behind what populations need, even for the most basic of requirements. This is not only a problem for the developing world, e.g. South America, Africa or India; it is also relevant in the UK, North America, and all of the first world. The housing situation is often referred to as a crisis and, as such, is not likely to be solved by continuing to build by traditional methods.

New building materials have been proposed. For example, geopolymer concrete is a relatively new invention that produces a sustainable and workable concrete with an exceptionally low carbon footprint in a process that avoids the use of OPC and the need for the high temperature firing of bricks. However, while studied by numerous universities and companies, to the knowledge of the present inventor, no truly practical system has been launched that allows this advanced technique to be used in mainstream construction.

Summary of the invention

The present invention seeks to provide a novel insulated building element/block construction that can be implemented across the building industry. Particularly, the invention demonstrates a way forward for geopolymer concrete and the potential for drastically reducing the carbon footprint of housing, whilst also delivering a system of manufacture and construction that the can be deployed, preferably by unskilled labour including by homeowners themselves, at rate commensurate with the need.

In a broad aspect the invention provides an insulated building element according to claim

1. The element is of sandwich construction comprised of a core insulating material (the 'core' - typically of high insulating performance) and two outer surface portions (herein called 'plates'- typically of geopolymer concrete or other similar material), where the core material is bonded or fixed with adhesive and/or otherwise fastened to the two outer surface plates. In its basic form the core and the plates are of the same size and shape. Whilst the plates remain parallel and in alignment with each other, the core is offset along two sides.

The arrangement is such that blocks (i.e. elements of a size that can be handled by a single construction worker) or panels (elements of similar profile but larger than blocks) can be simply joined horizontally as well as being stacked in a brick bonding method, to form a wall.

Additionally, to provide accurate placement of the elements one upon another, a profiling may be introduced along the edges (e.g. either two opposing edges or all four edges) of the core. This ensures extremely accurate placement of the elements and also adds to the horizontal resistance to movement.

The profile/surface features may be a series of ridges and/or corresponding channels, longitudinally or laterally, on upper and lower surfaces thereof, such that stacked elements (usually in brick bonding form) interconnect with each other.

In the present invention the building elements are manufactured to high levels of accuracy (i.e. <lmm tolerances) such that the construction process is deskilled. When combined with a 'tie bar' form of construction, the elements can be constructed 'dry', without the need to glue or cement any of them one to another, while at the same time forming exceptionally strong and stable structures.

In a tie-bar system, the elements have a number of holes vertically drilled/formed through them to enable the introduction of the tie-bars. A base plate is accurately mounted horizontally on a foundation to form a ring beam around the base of the building. Vertical tie-bars (e.g. of threaded steel, fiber reinforced plastic or other material) are locked down into the base plate via fixings in the base plates. Multiple base plates are commonly needed for a house or structure and these are connected one to another via bolted steel side plates that ensures the continuation of the horizontal base plate. This single structure represents a base level ring beam.

Elements are mounted on the base plates as previously described. At each floor level and/or at the roof level (the so called 'plate level') another top-plate/intermediate-plate is introduced on top of the elements and this is then screwed down to introduce a compressive force on the wall forming elements, between the base plate and subsequent levels. Accordingly, a two-story building will have three substantial ring beams made of high strength geopolymer concrete, providing exceptional strength and stability, whilst allowing the elements to be built dry.

A particular advantage of the system is that the insulating core alone provides a locking and locating interconnection between the adjoining elements, effectively providing a zero-loss system due to bridging. When this is combined with a compressive vertical tie bar system the outcome is a wall of exceptional strength and accuracy that is highly resistive to any form of cracking or deformity due to ground movement. The assembled wall can be plastered over or covered by any suitable means for aesthetic and additional insulation effect.

With regard to terminology, the building element is most likely provided in a 'block' form,

i.e. typically a compact, brick-like, unit in the context of building components. The invention can alternatively be described as a 'panel' if it is in the form of a unit with a larger outward surface area compared to its width across (i.e. wall thickness). The terms element, block, panel, brick, and cladding can be interchangeable in the context of the invention.

According to the invention, the core material is formed from high-density expanded polystyrene (EPS) or an equivalent material that has similar insulating and strength properties. The plates are made of high compressive strength (i.e. >50MPa) geopolymer concrete. When stacked in block form this has sufficient resistance to compressive forces but, in any event, is reinforced by the outer panels, being plates of geopolymer concrete. Interconnection of the elements is improved by the insulating core material having a surface feature and/or a profile on a side edge thereof corresponding to a mating feature of an adjacent element in use. Mating features located on an upper side edge and lower side edge of the core material respectively enable stacked building elements to interconnect with each other.

In one form the insulating core material includes at least one bore therethrough, for receiving a tie bar and/or fastening rod. A tie bar has application in a wider system. For example a plurality of building elements can be arranged with side edges of the core material abutting to assemble a wall. Then a base beam, upon which a first row of the plurality of building elements is arranged, can be tied to a capping beam located over the assembled wall to provide tension on the building elements between the base beam and capping beam.

In one form the outer panels may be pinned together, through the core material, to secure the building element in a permanent shape, as an alternative or in addition to adhesive bonding with the core material. Furthermore, pinning provides structural integrity and the relative spatial relationship of the outer panels is maintained in the absence or degradation of the core material.

The invention preferably utilizes an advanced composition of geopolymer concrete of high compressive strength for the outer surface portion, together with a high density expanded polystyrene (or other suitable material) core. However, alternative materials can be contemplated; for example, other forms of concrete or other surface materials which retain the structural advantages of the invention.

The core preferably provides high levels of insulation as well as an interconnecting and locking system. Overall the building element in block or panel form is a simple but high quality component for use in a walling process. In a particular form of system the blocks will be provided in a full size and other smaller size (e.g. half size, quarter size etc.) formats so that a series of full size units can be laid that are each offset from adjacent upper and lower parallel rows of units. A half size block may be required at alternate row ends to provide a straight edge to the wall. A corner element may be provided to connect multiple element walls at required angles. Particularly, there may be at least two types of L-shaped corner units used to connect adjoining walls at right angles, or another required angle. The L-shaped blocks may have differing length extensions to be compatible with staggered/offset layers of blocks assembled into a wall.

The construction system of the invention significantly reduces carbon emissions compared to traditional building. It allows faster, more accurate and higher quality construction at lower cost. In a very practical way, the invention can help to address the social problems of housing shortages while at the same time introducing a more sustainable system of building.

Some benefits of the system compared to traditional building are as follows:

• Using geopolymer concrete reduces harmful greenhouse gasses of traditional brick and cement manufacture by up to 90% • Can be three to four times faster to build than traditional twin-walled systems • Can be built by unskilled workers, thus avoiding the local and wider issue of skilled labour shortages • Likely to cost between 20 and 30% less to build • Results in very little waste, with an estimated <5% waste generated during the manufacture process and almost no waste on site. Traditional building is estimated to generate >35% waste on-site alone • Built 'dry' with no adhesives or cementing of components, thus no delay in waiting for the structure to dry before commencing internal work • Produces walls for houses that are stronger than traditional walling • Little or no 'shrinkage cracks' thus also reducing downstream snagging and maintenance.

• System works on the basis of all components being accurate to within one millimeter, meaning the exact size of rooms is known before construction begins, enabling the factory manufacture of nearly all internal and external fittings, further reducing costs and increasing quality • Highly resistive to ground movements, thus a significantly preferred option in areas prone to seismic or other earth movements • Foundation systems in most cases can be much 'lighter' than traditional systems as the building sits upon, rather than into, the ground • A single block system, not twin-walled, can have exceptionally high insulation rating, e.g. R values >5 (U values <0.19) • Mitigates the significant world-wide material shortage of bricks, breeze blocks etc.

• Meets one of the UK government's key housebuilding targets, i.e. it encourages and significantly simplifies the entry of small builders into the house building market.

In general terms the invention features a sandwich structured block or panel building element comprised of a high strength thin walled geopolymer concrete (GPC) outer layer for building integrity and an insulating core of high-density polystyrene providing thermal efficiency. The block also features a unique connecting and locking mechanism to provide simple and fast construction. The outer layers of geopolymer concrete (the 'plates') can be accurately manufactured (tolerances < 1mm) as well as being of a high compressive strength, which is advantageous for a thin-walled construction technique.

The resulting manufacturing accuracy of the elements allows walling systems to be fully constructed without the need for the individual blocks/panels to be glued, cemented or otherwise fixed directly together. The skill needed by the builder is thereby dramatically reduced and this allows building to be completed by unskilled workers at three to four times the construction rate of skilled artisans with traditional systems.

The system is also adapted for inclusion of windows. Capping plates can be provided for surrounding a window opening, where tie bars are then connected into the base beam and capping beam.

Brief description of the drawings

Figure 1 illustrates a general view of a building element according to one embodiment;

Figure 2 illustrates an end view of the building element according to Figure 1;

Figure 3 illustrates a plan view of the building element according to Figures 1 and 2;

Figure 4 illustrates a side view according to a second embodiment;

Figure 5 illustrates a general view of the building element according to Figure 4;Figure 6 illustrates a side elevation view of building elements according to the second embodiment being assembled into a wall; and

Figure 7 illustrates a side elevation section view of an embodiment of building constructed from building elements according to the invention.

Detailed description of an embodiment of the invention

Advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate various aspects and embodiments of the invention. However, the scope of the invention is not intended to be limited to the precise details of the embodiments, with variations apparent to a skilled person deemed also to be covered by the description of this invention.

Furthermore, terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features. Descriptive terms should also be given the broadest possible interpretation; e.g. the term comprising as used in this specification means consisting at least in part of such that interpreting each statement in this specification that includes the term comprising, features other than that or those prefaced by the term may also be present. Related terms such as comprise and comprises are to be interpreted in the same manner. Directional terms such as vertical, horizontal, up, down, upper and lower are used for convenience of explanation and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and/or direction. Furthermore, the present description refers to embodiments with particular combinations of features, however, it is envisaged that additional combinations and cross-combinations of compatible features between embodiments will be possible. Indeed, isolated features may function independently from other features and not necessarily be implemented as a complete combination.

A building element is illustrated in a basic form according to Figures 1, 2 and 3. As shown, the element, generally denoted 10, is comprised of a core material 11 and at least one outer surface portion 12, e.g. a plate or pair of plates. Figure 1 is shown as an exploded view where the core material and plate have a substantially aligned and equivalent side surface dimension.

However, the core material 11 is preferably bonded and/or otherwise fastened, e.g. by pinning, between two outer surface panels/plates in an offset configuration as shown in Figures 2 and 3. For example, relative to the core block material 11, outer plates 12 leave an overhang 13 on at least one, but preferably two edges. In this way adjacent elements can be further interconnected to form a self-supporting wall structure. It will be apparent from Figure 2 that a second like-shaped element 10 can be stacked upon the illustrated element to build a wall of the elements in a vertical direction. Said wall will be steadied in use by the interlocking nature of the overhanging lower end 13 with a protruding upper end 14, i.e. the edge of core 11 exposed from between panels 12 by virtue of the offset configuration. The bricks could be stacked with directly vertical alignment or, more preferably, by the traditional offset method used in brick laying where each subsequent layer is offset from the layer below by approximately half a length (as visible in Figure 7).

Figure 4 illustrates features of a further embodiment of a building element 20 where an offset outer surface portion/panel 22 overhangs two adjoining (lower right side as viewed) edges of a core material 21. The opposite (lower left as viewed) edge 23 of plate 22 is offset from a lower exposed edge of the core material, analogous to Figure 2, and an end (right side vertical as viewed) edge 25 of plate 22 is also visible as offset from the core material 21, analogous to Figure 3. A protruding upper edge 24 of core material 21 is visible, as is the left side end of core material 21 protruding from behind plate 22.

The core material includes surface features 26 which take the form of a profile on the exposed upper surface 24. In effect the profile features 26 provide for interconnection with the underside of core material 11 of an adjacent element when stacked, i.e. as is apparent from Figure 6 where the underside of core material 21 includes mating features 27 for receiving/interconnecting with the upper profile 26. The features may be a series of ridges and/or corresponding channels, longitudinally or laterally, on upper and lower surfaces thereof, such that stacked elements interconnect with each other.

Indeed, it will be apparent that a like-shaped building elements 20 can be stacked on top of each other, either in vertical alignment or, more preferably in an offset configuration as shown in Figures 6 and 7.

As generally shown, the building element 20 is a sandwich construction consisting of two thin walled outer plates 22, preferably made from geopolymer concrete or other high strength material, bonded to a central core 21 of insulation. Using GPC, the plates are likely to range in thickness between 10 and 20mm depending on the strength of the GPC and the specific requirement.

The core material, preferably formed of a block of polystyrene foam with impregnated graphite for improved insulation, may be bonded to the plates 22. In the embodiment of Figure 5, a rod/fastener/pin may be driven laterally through core 21, between plates 22, and secured to provide additional fixing/bonding. Only an end 28 of a pin is visible in

Figure 5 which could include a screw thread and/or driving feature. Four fixing points are shown but any appropriate number is possible. Such a feature provides stability while bonding adhesives set to a permanent state and structural integrity in the absence or upon degradation of a core material. However, in principle either method of fixing may be employed alone.

Figure 4 also shows a series of through holes/bores 29 in dotted detail which represent tubular voids to receive a tie bar for wall construction as will be described further below with reference to Figure 7.

All complete units preferably comprise exactly the same components, the only difference being that of size. While the overall size may alter, the cross width of the connecting cores 21 preferably remains consistent. This aspect allows elements of a variety of sizes to be interconnected without any loss of mechanical or thermal integrity and enables simple, flexible walling design and construction. Further, specialized components may be employed such as end and/or corner units that cooperate with a plurality of assembled building elements to aid construction of a wall/buiIding.

By way of example, elements may be produced in large panel sizes e.g. 3m high x 2m wide x 0.180m deep, or in block-type sizes of 500mm wide x 250mm wide x 180mm deep, or smaller. The element, by having a common width, will fit together easily and quickly to provide a highly insulated single piece wall, ideal for the construction of housing. However, differing standard sizes and depth panels can also be produced for walls for other purposes such as internal walls where the panels could be, by way of example, approximately 100mm depth.

The design of the exemplified panel/block system exhibits a number of highly desirable properties. For example:

• An assembled wall has exceptionally low thermal transmittance down to a U value of <0.19 with almost zero bridging. This is achieved by using the insulation core as the main connecting vehicle. Such an approach could seem surprising since an insulation like Expanded Polystyrene (EPS) is understood to have little strength of significance. However, when relatively large areas of a high-density polystyrene are used for positioning purposes in combination with high-strength concrete cladding, the combination has proved through testing to be very effective.

• The plates have a compressive strength typically >50MPa and are manufactured to a size tolerance of <lmm. This exceptional manufacturing precision, by virtue of the chosen material, allows the panels (even down to small block sizes) to be built dry and held in place mainly by a vertical compressive force introduced by a tie bar system. Clamping the blocks between top and bottom plates provides for the wall to exhibit the properties of a single element wall rather than a multi-element one. This allows much lighter foundations to be employed.

• The insulation core is profiled which provides two benefits. Firstly, it further increases the resistance to movement of the block effectively locking them into place. Secondly, during wall construction, each block automatically falls into a very accurately placed position that is pre-determined by the design and not by the skill of the individual. As a result, anyone can build with the system to an exceptional accuracy. Wall construction according to the method/system herein is thereby completely deskilled allowing unskilled workers, or practically anyone, to build quickly and accurately using the components provided. In disaster situations, e.g. where a settlement is ruined following an extreme weather event, local people can be involved in building their own housing replacement.

As described, the insulation material 21 (the core of the sandwich panel) performs the function of both an interconnection between panels as well as a locating and locking component, e.g. a profile along at least the top and bottom surface of the core, to prevent movement. An infinite number of profiling designs can be introduced to accomplish the same outcome.

The system allows the panels to be easily interconnected one to the other, both from side to side and top to bottom whilst eliminating any form of bridging. Figures 4 to 6 show profiling on the top 26 and bottom 27 faces only, although profiling on all four exposed sides (i.e. those faces not attached to a plate 22) is also envisaged. Such surface features (26/27) allow each block or panel to be built both horizontally and vertically depending on design or other criteria. For example, in a wall using block size elements, more complex designs of constructions such as herringbone may be employed.

In an embodiment of the invention illustrated by Figure 7 a plurality of building elements 20 (blocks/panels) can be assembled into a wall structure 30 and secured by use of a tie bar system 31. Particularly, building elements as described above are combined with an upper capping beam 32 and a bottom base beam 33 (referred to hereinafter with reference to Figure 7 as 'top plates' and 'bottom plates') and a tie bar 31 is arranged to extend through the building elements, e.g. through bores 29 visible in Figure 3. The tie bars 31 (e.g. a threaded rod or fiber reinforced plastic, etc.) are mechanically fixed into the plate(s) 32, 33, typically by screwing or another suitable fixing system. When bolted onto the top plates 33, having passed through holes 29 in the cores 21, they provide a significant compressive force on all of the block/panel elements 20 within the assembled wall 30. This then provides an effective and stable walling system.

In one form both top 32 and bottom 33 plates are made of GPC to a variety of lengths. Most structures will require the adjacent plates to be joined together and connecting plates (of steel or other materials, not shown) can be employed to ensure the continuation of integrity across multiple wall assemblies. Such a feature results in another significant advantage.

With the base plates 32 and top plates 33 connected in this way, each level effectively forms a ring beam around all walls of the level, and therefore a building structure may have two or more ring beams; the top plate (forming one ring beam with adjacent top plates at the same level) being repeated at every floor level such that a typical two-story house with this system has three ring beams, a three story building has four and so on. The combined structural system will exhibit a box-like form of exceptional strength, rigidity and resistance to ground movement or failure.

The erected building rests upon a foundation 34, but this foundation has more flexibility of design and can be particularly economical since the building itself provides its own integral support.

The illustrated system is adapted for inclusion of windows (not illustrated). For example a window opening can be formed by strategic layering of the building elements during construction. Capping plates can be arranged to surround the internal surfaces of the opening formed for receiving a window frame. Tie bars from lower and upper capping plates are then connected into the base beam and capping beam respectively so that the opening in the wall has relatively minimal effect on the overall strength.

In connection with the manufacturing process of a geopolymer concrete material suitable for use with the present invention, a Fly Ash (FA) and Ground Granulated Blast Furnace

Slag (GGBFS) are used together with aggregates and either Potassium Silicate and Potassium Hydroxide or the Sodium alternatives. After mixing these are then cured, e.g for 24 hours in ambient temperatures and then further cured at 60°C for 24 hours. This formula provides not only a high compressive strength of >50MPa, but also a manageable material that is able to be accurately manufactured to the desired shape and size.

The GPC production process is intended to be operated in a relatively small production facility on a continuous 24/7 basis.

Claims

CLAIMS:

1. A building element comprised of:

an insulating core material; and outer panels located on opposite sides of the insulating core material;

wherein the outer panels are bonded and/or fastened to lateral sides of the core material in an offset configuration providing an overhang with at least one side edge of the core material, for an adjacent building element to, in use, interconnect therewith.

2. The building element of claim 1, wherein a side edge of the core material, opposite to the overhang, is exposed from between the outer panels.

3. The building element of claim 1 or 2, wherein there is an overhang over two side edges of the core material.

4. The building element of any preceding claim, wherein the insulating core material is generally block, brick or panel shaped.

5. The building element of any preceding claim, wherein the outer panels are formed from geopolymer concrete.

6. The building element of any preceding claim, wherein the insulating core material is formed from polystyrene.

7. The building element of any preceding claim, wherein the insulating core material includes a surface feature and/or a profile on a side edge thereof for providing interconnection with the core material of an adjacent element in use.

8. The building element of claim 7, wherein the surface feature and/or profile is a series of ridges and/or corresponding channels, longitudinally or laterally.

9. The building element of claim 7 or 8, wherein the surface feature and/or profile is located on an upper side edge and lower side edge of the core material such that, in use, stacked building elements interconnect with each other.

10. The building element of any preceding claim, wherein the insulating core material is bonded to the outer panels by an adhesive.

11. The building element of any preceding claim, wherein the insulating core material is fastened between the outer panels by a fastening rod or pin extending laterally from a first panel to a second panel, through the core material.

12. The building element of any preceding claim, wherein the insulating core material includes at least one bore therethrough, for receiving a tie bar and/or fastening rod.

13. A system of building construction, implementing a plurality of building elements according to any preceding claim, wherein:

the plurality of building elements are arranged with side edges of the core material abutting to assemble a wall.

14. The system of building construction of claim 13, further including:

a base beam, upon which a first row of the plurality of building elements is arranged; and a capping beam located over the assembled wall;

wherein at least one tie bar is fixed to provide tension between the base beam and capping beam for compression on the building elements.

15. The system of building construction of claim 14, wherein a second level wall of building elements is assembled upon the capping beam and a further level capping beam is located over the second level wall, including a tie bar fixed to provide tension between the capping beam and further level capping beam for compression on the building elements.

16. The system of any of claims 11 to 14, further including end piece and/or corner elements to cooperate with an edge of one or more of the plurality of building elements, to provide an adjoinment with an adjacent wall.

16. The system of any of claims 14 to 15, wherein a plurality of walls are constructed, forming a building structure, each wall including a base beam and a capping beam, the base beams being connected to form a base ring beam and the capping beams being connected to form a capping ring beam.

17. The system of any of claims 14 to 16, wherein an opening for a window is formed in the wall, being surrounded by a plurality of building elements, and including a capping plate at at least one edge of the opening, wherein at least one tie bar is fixed to provide tension between the capping plate and the

10 base beam and/or capping beam.

18. The system of any of claims 13 to 16, further including end piece and/or corner elements to cooperate with an edge of one or more of the plurality of building elements, to provide an adjoinment with an adjacent wall.

Amendments to the claims have been filed as follows

CLAIMS:

1. A building element comprised of:

an insulating core material; and outer panels formed from geopolymer concrete located directly against opposite sides of the insulating core material;

wherein the insulating core material includes a surface feature on a side edge thereof, a side edge being a surface of the insulating core material not located directly against an outer panel, for, in use, providing interconnection with a corresponding surface feature on an adjoining side edge of core material of an adjacent building element; and wherein the outer panels are bonded and/or fastened to opposite sides of the core material in an offset configuration providing an overhang with at least one side edge of the core material, for an adjacent building element to, in use, interconnect therewith.

4. The building element of any preceding claim, wherein the insulating core material is a brick shape.

5. The building element of any preceding claim, wherein the insulating core material is formed from polystyrene.

6. The building element of any preceding claim, wherein the surface feature is a series of ridges, longitudinally or laterally.

7. The building element of claim 6, wherein the surface feature is located on an upper side edge and lower side edge of the core material such that, in use, stacked building elements interconnect with each other.

8. The building element of any preceding claim, wherein the insulating core material is bonded to the outer panels by an adhesive.

9. The building element of any preceding claim, wherein the insulating core material is fastened between the outer panels by a fastening rod or pin extending laterally from a first panel to a second panel, through the core material.

10. The building element of any preceding claim, wherein the insulating core material includes at least one bore therethrough, for receiving a tie bar or fastening rod.

11. A system of building construction, implementing a plurality of building elements according to any preceding claim, wherein:

12. The system of building construction of claim 11, further including:

13. The system of building construction of claim 12, wherein a second level wall of building elements is assembled upon the capping beam and a further level capping beam is located over the second level wall, including a tie bar fixed to provide tension between the capping beam and further level capping beam for compression on the building elements.

14. The system of any of claims 12 to 13, wherein a plurality of walls are constructed, forming a building structure, each wall including a base beam and a capping beam, the base beams being connected to form a base ring beam and the capping beams being connected to form a capping ring beam.

15. The system of any of claims 12 to 14, wherein an opening for a window is formed in the wall, being surrounded by a plurality of building elements, and including a capping plate at at least one edge of the opening, wherein at least one tie bar is fixed to provide tension between the capping plate and the

10 base beam and/or capping beam.