BUILDING A CONSTRUCTION FOUNDATION

Technical Field of the Invention

The invention relates to a construction foundation element, a method for manufacturing said construction foundation element and a method for building a construction foundation using said foundation element. More specifically, the present invention is related to a prefabricated construction foundation element comprising a top layer, an insulation layer arranged below the top layer, and a reinforcement layer arranged along at least one edge area of the foundation element, below the top layer and externally of the insulation layer. Foundation elements of this type are generally used for construction of buildings, such as residential houses, commercial buildings and similar.

Background

Construction foundations for buildings are usually made from cement or concrete, cast in-situ on top of a layer of insulating material. The insulating layer prevents thermal loss from the floor inside the finished construction. Depending on soil conditions, it is also common to provide a capillary barrier, usually in the form of a layer of pebbles or gravel beneath the insulation material.

The concrete foundations are generally cast at the building site using moulds and steel reinforcement bars to support and shape the fluid concrete. When the concrete has set, the construction work continues.

However, the setting of the concrete can take a long time and the concrete can be moist for several months depending on the thickness and size of the construction foundation, which in turn causes delay of the construction project. Hence, laying of a floor on the foundation element can be delayed and if a wooden floor is arranged on top of the foundation element to soon it can be ruined. Alternatively, precautions have to be taken to avoid water from migrating into a wooden floor or other floor types, which may cause further implications and costs.

Several attempts have been made to provide foundation element which facilitate the construction process and to make it more effective. For instance, GB2571504 comprises a foundation slab, preferably made of concrete, a base foundation layer located on the slab and a pre-fabricated module on the base foundation layer. The building module includes on its bottom surface a module foundation layer. The module foundation layer may include cut out channels for receiving pipe work for water and the base foundation layer and the module foundation layer may be made from insulating expanded polystyrene. However, this solution still relies on concrete and cement, which are non-environmentally friendly materials, giving rise to pollution and which are difficult to recycle when needed. In addition, the concrete must be allowed to set, and the manufacturing of the module foundation layer requires a cutting step.

Hence, there is a need for an improved construction foundation, which may enable construction work to progress faster and which is believed to be more environmentally sustainable.

Summary of the Invention

According to a first aspect of the invention, the above and other objects of the invention are achieved, in full or at least in part, by a construction foundation as defined by claim 1. According to this claim the above object is achieved by a prefabricated construction foundation element comprising a top layer, an insulation layer arranged below the top layer, and a reinforcement layer arranged along at least one edge area of the foundation element, below the top layer and externally of the insulation layer. The top layer and the reinforcement layer comprise a wooden material. The insulation layer comprises at least two sections of load bearing insulation spaced apart such that at least one installation space is formed therebetween, wherein said installation space is filled with a non-load bearing insulation. The sections of load bearing insulation are distributed below the top layer in a plane parallel to a plane of the top layer. For example, the sections of load bearing insulation are distributed in a horizontal plane below the top layer. For example, the installation spaces are formed between the sections of load bearing insulation in the same horizontal plane as said sections of load bearing insulation. For example, the top layer extends in a horizontal plane and is supported by the load bearing insulation, either directly or indirectly. The top layer may be a wooden top layer and/or the reinforcement layer may be a wooden reinforcement layer. The load bearing insulation may be a relatively hard insulation material, whereas the non-load bearing insulation may be a loose insulation material. For example, the load bearing insulation is harder than the non-load bearing insulation.

This prefabricated foundation element has several advantages. Firstly, the use of wood for the top layer and the reinforcement layer results in a prefabricated foundation element being lighter than e.g. a foundation element formed from concrete. The low weight facilitates transport since vehicles have weight restriction requirements.

Secondly, wood is a sustainable and recyclable material, as opposed to e.g. cast concrete foundations having larger negative impact on the environment. It has been shown that the carbon footprint of the foundation elements disclosed herein is decreased compared to the carbon footprint rendered by a corresponding concrete foundation.

Thirdly, the prefabricated foundation elements results in a fast assembling process and the forming of a construction foundation does not require any drying period before the construction process may continue. Hence, when a foundation has been assembled, e.g. by providing a plurality of foundation elements adjacent to each other and, optionally, also opposite each other on a horizontal surface on a building site, a flooring finish can be arranged on top of the wooden top layer, such as directly on top of the wooden top layer, without delay.

Moreover, since the installation spaces(s) provides room for MEP-installations, there is no need to saw/cut recesses in the hard load bearing insulation for such installations. This also saves time and energy during the construction process. The application of loose insulation material in the installation space(s) around MEP- products provides favourable and efficient insulation in the foundation element, with at least reduced voids. The loose non-load bearing insulation can also contribute to the installations being held in place inside the installation spaces. Further, the arrangement of the hard load-bearing insulation can be adapted depending on each specific building, making the construction process more simple and faster. In one embodiment, the foundation element further comprises a layer of hard load bearing insulation arranged below and in parallel with the reinforcement layer, and externally in relation to the insulation layer.

In another embodiment, the foundation element further comprises a bottom diffusion barrier arranged as a bottom layer of the foundation element, under the reinforcement layer and the insulation layer. This barrier protects the foundation element from moisture which may penetrate the foundation element from below is placed in a humid environment.

The wooden top layer and the wooden reinforcement layer may be formed in engineered wood or solid wood. In one embodiment, the wooden top layer and/or the wooden reinforcement layer is/are formed in cross-laminated timber (CLT). The CLT is preferable since it prevents shear in the wood, due to that the cross-laminated parts of the CLT provides an improved structural rigidity in several directions.

In one embodiment, the wooden top layer further comprises prefabricated machined grooves for receiving cables, pipes, underfloor heating and/or plumbing. Further, in a second embodiment, the wooden top layer is formed with a hole and a machined inclination area towards the hole for forming a floor drain. These prefabricated designs are beneficial since they accelerate and facilitate the construction process. Moreover, the wooden top layer can be provided with grooves, holes and inclination areas with high precision, e.g. with a precision of 10 mm or less, such as 5 mm or 3 mm and e.g. with conventional tools for wood machining and drilling, compared to when conducted in conventional concrete foundations on site.

The wooden top layer may comprise prefabricated machined grooves for receiving cables, pipes, underfloor heating and/or plumbing. Further, the wooden top layer may be formed with a hole and a machined inclination area towards the hole for forming a floor drain. This facilitates and saves time in the construction process.

In another embodiment, the foundation element further comprises an edge insulation barrier arranged along at least one side edge of the foundation element. This is beneficial in that the insulation barrier may protect and insulate the side edge(s) of the foundation element. The foundation element may comprise an outer envelope arranged as an outer edge surface of at least one side edge of the foundation element.

Preferably, the hard load bearing insulation is made of expanded polystyrene (EPS). This is advantageous in that EPS is cheap and abundant. It is available in standard dimensions suitable for the foundation element. Further, EPS is load bearing and help to distribute the load from the building placed on top of the construction foundation. As an alternative to EPS other types of extruded products such as XPS can be used.

The loose non-load bearing insulation may be made of a non-organic permeable insulation material, such as a mineral wool, or cellulose insulation. Cellulose insulation is advantageous since it is a sustainable material, thus lowering the carbon footprint of the foundation element even further. The permeable insulation being soft prevents formation of voids comprising no insulation in the foundation element, and can be pushed into the installation space(s) before or after MEP -installations have been installed in the installation space(s).

In one embodiment, the foundation element comprises a layer of loose non load bearing insulation, arranged between the insulation layer and a side surface of the foundation element and/or wherein the foundation element comprises a layer of hard load bearing insulation arranged between the insulation layer and the side surface of the foundation element.

The top layer may further comprise a metal sheet panel. Preferably such metal sheet panel is a profiled steel sheet panel. This further decreases the production cost of the foundation element, and the profiled steel sheet panel can harbour heating cables or hoses and the like in its profiles such that milling of the wooden parts of the top layer is no longer needed. Further, the foundation element is lighter than e.g. a foundation element formed from concrete, and requires no drying period.

In a second aspect, there is provided a method for building a construction foundation with a plurality of prefabricated construction foundation elements as disclosed herein. The method comprises the steps of providing at least two prefabricated foundation elements, arranging the foundation elements next to each other on a base layer or support structure, and attaching the foundation elements to each other using an adhesive or a fastening means.

This method is advantageous since it is quick and easy, and does not require a long period of setting time, as for instance required when forming a concrete construction foundation. Hence, the construction process may proceed immediately after the construction foundation is formed.

In one embodiment, the method further comprises a step of installing installations in an installation space or in prefabricated machined grooves and/or holes of the foundation element. For example, the installations are cables, electric wires, plumbing, ventilation and/or water pipes. This is beneficial since it accelerates the construction process and the installations can be installed with high precision. After installation of such installations, the installation space may be provided with non bearing insulation material.

In a third aspect, there is provided a method of manufacturing a prefabricated construction foundation elements. The method comprises the steps of arranging a reinforcement layer on a bottom side of a top layer and along at least one edge area of the top layer and arranging an insulation layer below the top layer and on an internal side of the reinforcement layer. The insulation layer is formed by arranging at least two sections of load bearing insulation on the bottom side of the top layer, forming at least one installation space between the at least two sections of load bearing insulation. The method further comprises installing mechanical, electrical and/or plumbing engineering installations (MEP-installations) in the installation space(s) and providing the installation space with non-load bearing insulation.

This method is advantageous in that the foundation element is easy to assemble and provides space for MEP-installations which can be installed before or after the installation space(s) is/are provided with non-load bearing insulation. Hence, the foundation elements can be delivered to the building site already having MEP- installations in place. Also, the method for manufacturing the foundation element can be adapted such that the installation spaces formed by the arrangement of the load-bearing insulation is designed depending on the needs of a specific building. Other objectives, features and advantages of the present invention will appear from the following detailed disclosure, from the attached claims, as well as from the drawings. It is noted that the invention relates to all possible combinations of features.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the [element, device, component, means, step, etc.]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

As used herein, the term “comprising” and variations of this term are not intended to exclude other additives, components, integers or steps.

Brief description of the Drawings

By way of example, embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

Figure la shows a cross-sectional side view of a prefabricated construction foundation element according to one embodiment;

Figure lb shows a cross-sectional side view of the embodiment of Fig. la, comprising further optional features;

Figure 2 shows a sectional top view of the prefabricated construction foundation element shown in Fig. la;

Figure 3 shows a sectional top view of the prefabricated construction foundation element according to another embodiment;

Figure 4a and 4b show two different cross-sectional side views of the prefabricated construction foundation element shown in Fig. 3;

Figure 5 shows a sectional top view of a prefabricated construction foundation element according to yet another embodiment;

Figure 6 shows a schematic view of a construction foundation comprised from a plurality of prefabricated construction foundation elements showed in Figs 1 to 5; Figure 7 shows a cross-sectional side view of a building arranged on top of a construction foundation according to one embodiment; and

Figure 8 shows a flow chart for a method of building a construction foundation using the prefabricated foundation elements disclosed herein; and

Figure 9 shows a flow chart for a method of manufacturing a foundation element according to the invention.

Detailed Description of Preferred Embodiments of the Invention

The invention relates to a prefabricated construction foundation element, also referred to as a foundation element herein, and the construction of a construction foundation using the foundation elements. With reference to Fig. 1, a cross-section of a prefabricated construction foundation element 100 seen from the side is shown. The foundation element 100 is arranged for construction of foundations for buildings, including residential houses as well as commercial buildings and apartment buildings. For example, foundation element 100 is arranged to be positioned horizontally or substantially horizontally. As shown in Fig. la, the foundation element 100 has a vertical central axis C, and a lateral axis A.

Further, the foundation element 100 has a height H and comprises a top layer 110 and a reinforcement layer 115. The top layer 110 comprises a wooden material and may, e.g. be a wooden top layer 110. Alternatively, the top layer 110 comprises a frame of a wooden material and insert plates of another material, such as metal. The metal may be a profiled metal sheet panel, such as a profiled steel sheet panel, also referred to as a corrugated steel sheet panel. However, in the described embodiment example below, the top layer 110 is a wooden top layer. The reinforcement layer 115 comprises a wooden material and may, e.g. be a wooden reinforcement layer 115. The reinforcement layer 115 is placed along short edges of the foundation element 100, as shown in Fig. l a.

For example, the wooden top layer 110 and the reinforcement layer 115 are formed from solid wood or an engineered wood, such as cross-laminated timber (CLT). For example, the wooden top layer 110 and the reinforcement layer 115 are formed from CLT made of spruce wood. However, any type of wood may be used to form a CLT. The wooden top layer 110 is arranged as a board having a top surface and a bottom surface connected through side edges.

For example, the wooden top layer 110 is a continuous board extending substantially in one plane. For example, the wooden top layer 110 is substantially flat and optionally arranged with a substantially uniform thickness. The reinforcement layer 115 is arranged as a board having a top surface and a bottom surface connected through side edges. For example, the reinforcement layer 115 is a continuous board extending substantially in one plane. For example, the reinforcement layer 115 is substantially flat and optionally arranged with a substantially uniform thickness. The wooden top layer 110 is arranged on top of the wooden reinforcement layer 115, wherein the wooden top layer 110 is arranged in parallel with the wooden reinforcement layer 115. If the foundation element 100 is rectangular in shape, the reinforcement layer 115 may be arranged along one or more of the short edges and/or one or more of the long edges of the foundation element 100. Independent of shape of the foundation element 100, the re inforcement layer 115 may be arranged along one or more of the edges of the foundation element 100.

For example, the wooden top layer 110 is attached to the wooden reinforcement layer 115 by an adhesive and/or fastening means, such as screws or similar conventional fastening means for fastening boards of wood to each other.

The use of wood for the top layer 110 and the reinforcing layer 115 provides a sustainable foundation element 100 having a lighter weight than e.g. foundation elements made from concrete or cement. The wood also facilitates the prefabrication process, since it does not need any setting and drying time, whereby the construction process of the building on top of the wood based foundation element 100 can continue immediately in various embodiments and at least without substantial delay in other embodiments. Moreover, the lightness and prefabrication makes the foundation elements 100 easy to handle and the process for forming a construction foundation using such foundation elements 100 is a quick and easy process.

In addition, the use of wood is considered to be a more environmentally friendly option than using concrete or other non-recyclable materials. Further, as will be explained more in the following, the wooden top layer 110 can be engineered to specific needs of the construction to be built on top since the wood top layer 110 can be machined/milled to include holes, grooves or inclinations which greatly contribute to an easier construction process.

Adjacent to the wooden top layer 110 and the wooden reinforcement layer 115, along at least one side edge of the foundation element 100, the foundation element 100 has an edge insulation barrier 120. As shown in Fig. 1, the edge insulation barrier 120 is arranged along the vertical sides of the foundation element 100, outermost from the wooden top layer 110 and the wooden reinforcing layer 115.

For example, the edge insulation layer barrier 120 protects the foundation element 100 from moisture and coldness which otherwise could penetrate into the foundation element 100 from the side edges. The edge insulation barrier 120 extends along a side edge of the wooden top layer 110 and the wooden reinforcement layer 115 and for example along the entire side edge of the foundation element 100. For example, the edge insulation barrier 120 is formed as a plate extending in a plane substantially perpendicular to the wooden top layer 110. The edge insulation barrier 120 is preferably formed from expanded polystyrene (EPS), rock wool or other insulation materials known in the art.

Below the wooden top layer 110 and between the two wooden reinforcement layers 115 there is an insulation layer 130. The top of the insulation layer 130 in Fig. la is arranged in the same height level within the foundation element 100 as the wooden reinforcements 115, and extends from the wooden reinforcement 115 in a direction opposite the edge insulation layer 120. The insulation layer 130 extends centrally towards the central axis C from the reinforcement layers 115, along the lateral axis A.

The insulation layer 130 comprises sections of load bearing insulation 116, also referred to as hard, load bearing “islands”, in the insulation layer 130. Between said sections of load bearing insulation 116, installation spaces 117 are formed. Four installation spaces 117 are shown in Fig. la. However, the foundation element 100 may comprise fewer or more load bearing islands 116 and/or installation spaces 117 than what is shown in Fig. la. The foundation element 100 preferably comprises at least two load bearing islands 116 to form at least one installation space 117. For example, the sections of load bearing insulation 116 are distributed in a plane parallel to and below a plane of the top layer 110, such as a horizontal plane, while forming the installation spaces 117 between the sections of load bearing insulation 116 in the same plane. For example, sections of load bearing insulation 116 and installation spaces 117 are arranged alternatingly in the lateral direction along the lateral axis A. Further embodiments of the arrangement of the load bearing islands 116 and the installation spaces 117 are shown in Figs 4 and 5 and will be explained in more detail with reference to these Figures.

The installation spaces 117 are configured to hold mechanical, electrical and/or plumbing engineering installations (MEP-installations). MEP -installations are not shown in Fig. la.

Further, the installation spaces 117 are provided with insulation material 118, as shown in Fig. la. The insulation material 118 in the installation spaces 117 is a non load bearing insulation material, such as a soft loose insulation material. Hence, the non-load bearing insulation material 118 may be soft and loose compared to the load bearing insulation material 116. The load bearing insulation material 116 is referred to as a hard load bearing insulation material below, wherein the non-load bearing insulation material 118 is referred to as a loose insulation material. Thus, the loose insulation material 118 encloses the MEP-installations in the installation spaces 117 once installed. The insulation material 118 in Fig. la is indicated by the wave like pattern. The application of loose insulation material 118 around MEP-products improves insulation in the foundation element 100, and reduces voids without insulation material. The loose non-load bearing insulation 118 may also contribute to holding the installations in place inside the installation spaces 117.

Moreover, the installation spaces 117 formed of sections of load bearing insulation 116 removes or at least reduces the need to cut, saw or mill the foundation element 100 to provide space for MEP-installations. This saves both time and energy, and in the end thus reduces the cost.

The use of loose insulation material 118 between the load bearing insulation 116 lowers the demand on the precision of how the hard load bearing insulation 116 is placed. The installation spaces 117 gives enough room to adjust various MEP- installations adapted on the specific building project, since the loose insulation 118 can be manipulated depending on the MEP-installation. This also lowers the cost of production.

MEP -installations includes among others electricity cables, ventilation, pipes and other installations which may be drawn through the foundation element 100. In such case, e.g. cables are installed in the installation space 117 and extracted through the wooden top layer 110 at a predetermined position adapted for the building to be constructed on top of the foundation element 100. As indicated in Fig. la, the four installation spaces 117 extend substantially in a horizontal direction through the foundation element 100, so that cables, pipes and/or similar can extend in a horizontal direction under the wooden top layer 110 between desired positions and then, if desired, vertically through a hole made in the wooden top layer 110 at the desired location.

The hard load bearing insulation islands 116 may be formed from expanded polystyrene (EPS).

Preferably, the loose insulation 118 is made of a cellulose insulation material or other insulation materials known in the art. The cellulose insulation material is recyclable and an environmentally friendly insulation material. Hence, the use of cellulose insulation material lowers the carbon footprint of the foundation element 100.

As can be seen in Fig. la, a portion 116b, also referred to as a layer 116b arranged below the wooden reinforcement layer 115 also supports the wooden reinforcement layer 115. Fig. la shows how, below each reinforcement layer 115, the layer of hard load bearing insulation 116b is arranged between the edge insulation barrier 120 and outermost loose insulation 118 of the insulation layer 130. The portion of hard load bearing insulation 116b is arranged in parallel with the reinforcement layer 115 and the top layer 110. The portion of hard load bearing insulation 116b extends from the edge insulation barrier 120 and centrally therefrom, towards the central axis C.

The hard load bearing insulation islands 116 are for example formed as plates extending substantially in parallel with the wooden top layer 110. Such plates preferably have industry standard measurements, such as 600x1200 or 1200x2400 mm. This saves time during manufacturing, compared to when using custom cut hard load bearing insulation. The dimensions of the hard load bearing islands 116 affect the desired thickness of the wooden top layer 110, and vice versa. Since the hard insulation islands 116 are load bearing, larger hard load bearing islands 116 con compensate for a thinner wooden top layer 110, while a thicker wooden top layer 110 can bear the construction placed on top with fewer and/or smaller dimensioned load bearing portions 116.

Preferably, the wooden top layer 110 has a thickness of between 60 and 250 mm, such as between 60 and 140 mm, such as between 80 mm and 120 mm, preferably, the thickness is about 100 mm. These dimensions are preferable since they are standard measurements within the field of construction and hence facilitate the manufacturing of the foundation elements 100. Standard dimensions results in that no cutting of the wooden top layer 110 or the hard load bearing insulation 116 is needed during the manufacturing process.

A wooden top layer 110 thicker than 100 mm results in a heavy prefabricated foundation element 100 and a thickness thinner than 60 mm will not provide sufficiently satisfying results. The wooden top layer 110 is stiff and rigid, which is of importance for stability of the foundation element 100 such that it may be covered with for instance floating screed which may be tiled on top without any crack formation.

Finally, the foundation element 100 in Fig. la is provided with a moisture barrier layer 140, which protects the foundation element 100 from moisture and humidity stemming from the ground, bottom plate or structure onto which the foundation element 100 is placed. For example, the sections of load bearing insulation 116 are arranged between the top layer 110 and the moisture barrier layer 140 for transferring load from the top layer 110 to the moisture barrier layer 140.

With reference to Fig. lb, a cross-sectional side view of the foundation element 100 of Fig. la with additional optional features is shown. The prefabricated foundation element 100 shown in Fig. lb further comprises an edge layer in the form of an outer envelope 150. The outer envelope 150 protects the foundation element 100 from the environment and prevents moisture from penetrating into the foundation element 100. The outer envelope 150 covers the edge insulation barrier 120.

Further, between the insulation layer 130 and the wooden top layer 110 in Fig. lb, there is an optional intermediate insulation layer 135, comprised of a non-organic permeable insulation material. The intermediate insulation layer enhances the transportation of humid air and allows for dehydration of the foundation element 100 in case of leakages from above. A leakage may stem from for instance, a broken sealing layer in a bathroom or a water leak in a kitchen and the like. Hence, the intermediate insulation layer is preferably applied on those foundation elements 100 arranged below wet rooms such as kitchens, bathrooms, laundry rooms et c.

Another optional feature of the foundation element 100 is a humidity sensor (not shown) which may sense possible water leakages from the construction built on top.

Furthermore, the foundation element 100 may be provided with a metal sheet plate or panel (not shown), which is preferably a profiled steel sheet panel. Instead of a top layer 110 comprised solely of wood, the top layer 110 can partly be formed from a wooden material, and partly from a profiled metal sheet panel (not shown). The profiled steel sheet panel is advantageous if for instance heating cables or hoses are to be installed in the top layer 110, since these installations fit in the corrugations/profiles of the metal panel. Thus, there is no need to mill any recesses or cavities for the installations, and there is no need for heat distributing plates which are often used in wooden floor based hearing.

In addition, the substitution of part of the wood of the top layer 110 for a metal sheet plate lowered the production cost, since metal sheet plates are less expensive than wood. Further, it is possible to substitute parts of the top layer 110 which do not require any milling to prepare the foundation element 100 for the building to be placed thereon. For example, those areas of the foundation element 100 where there is a need for e.g. through holes or machined inclinations in the top layer 110 are preferably comprised of wood while those parts not requiring any machining may be formed from the metal sheet panel material. The top layer 110 may comprise wooden material as a wooden frame along the edges of the foundation element 100, and metal sheet panels in the centre of wooden frame of the top layer 110 (not shown).

By having the top layer 110 comprising both wood and metal sheets, the foundation element 100 is inexpensive to produce, ready to use directly once manufactured, and is still more environmentally friendly than a concrete based foundation element known in the art.

Fig. 2 shows a section taken in a plane of the foundation element 100, at the height H of the foundation element 100 along the dashed lateral axis line A shown in Fig. la. The foundation element 100 comprises, as described above, islands of load bearing hard insulation 116, four installations spaces 117 filled with loose non-load bearing insulation 118, and reinforcement layers 115 arranged along the edges of the foundation element 100. In addition, the foundation element 100 comprises the outer envelope 150 and the edge insulation barrier 120.

The sectional view as seen from above the foundation element 100 in Fig. 2 also shows optional side edge boards 160 arranged along the long side edges of the foundation element 100. For example, the side edge boards 160 are mineral wool boards, such as rock wool boards. For example, the side edge boards 160 have a thickness of 20 to 100 mm, such as about 50 mm.

An optional diffusion barrier 170 may also be provided. The diffusion barrier 170 is configured to protect at least the wooden reinforcement layer 115 and the wooden top layer 110. The diffusion barrier 170 is e.g. a construction foil.

With reference to Fig. 3, a foundation element 100 according to another embodiment is shown. Fig. 3 also shows a sectional a top view. The foundation element 100 comprises three hard load bearing insulation portions 116, and four installation spaces 117 filled with loose non-load bearing insulation 118. Further, the foundation element 100 has reinforcement layers 115 arranged along the short edges thereof, and an edge insulation barrier 120 on each outer edge surface on the shorter ends. In addition, the foundation element 100 is provided with two laterally extending layers of loose insulation 118’, arranged on each side of the insulation layer 130. Further, on the external side of the layers of loose insulation 118’, there is arranged on each side a layer of hard load bearing insulation 116’. The layers of hard and loose insulation 116’, 118’ extend in parallel with the top layer 110 (not shown in Fig. 3) and between the reinforcement layers 115.

Fig. 4a and 4b, each shows a side view of a cross-section taken along the lines A-A, and B-B, respectively. As shown in Fig. 4a, this cross-section corresponds to the same view as shown in Fig. la. Hence, Fig. 4a is identical to Fig. la. Fig. 4b shows a cross-section taken along B-B indicated in Fig. 3. Since this cross-section is taken along the area where the layer of hard load bearing insulation 116’ is provided, no installation spaces 117 are visible in Fig. 4b.

Fig. 5 shows a foundation element 100 according to yet another embodiment. The section in Fig. 5 is also a top view, and the section has been taken in the plane of the foundation element 100, which comprises an insulation layer 130 having two hard load bearing insulation portions 116, four installation spaces 117 filled with soft, non load bearing insulation 118, reinforcement layers 115 arranged along the short edges thereof, and an edge insulation barrier 120 on each outer edge surface on the shorter ends. As shown in Fig. 5, in this embodiment, the foundation element 100 comprises yet another layout of the insulation layer 130. The two outermost installation spaces 117 are arranged in parallel with the reinforcement layers 115, extending perpendicularly to the lateral axis A, e.g. throughout the foundation element. The two most central installation spaces 117 overlap and form a continuous central installation space perpendicular to the lateral axis A and in parallel to the outermost installation spaces 117. The two hard load bearing portions 116 have a length which is less than half the length of the insulation layer 130 and extend along the lateral axis A. Hence, the installation spaces 117 formed in the centre of the insulation layer 130 overlap each other in the lateral direction. The two hard load bearing portions 116 extend from the outermost installation spaces 117 towards the centre axis C of the foundation element 100.

The construction foundation elements 100 are prefabricated and designed depending on the needs of the building to be built on top. The wooden top layer 110 may be machined, e.g. by milling, to include grooves/holes for electric wires, water pipes, sewage, plumbing, floor heating and the like. The milling may be performed using a Computer Numerical Control (CNC) tool, which operates from CNC-coded software designed drawings, resulting in very high precision of the cutting/milling and design of the prefabricated foundation elements 100. The wooden top layer 110 is preferably milled such that it is adapted to the MEP -installations drawn in the installation spaces 117. Hence, the milling of the top layer 110 can serve the purpose of holding MEP -installations draw in the installation spaces 117, and to provide recesses/cavities for other installations, such as floor heating or walls of the building to be constructed on top of the foundation element 100.

A CNC-tool may mill with a precision of 3 mm, which is better than the precision achieved when making such holes, indentions and/or grooves at site in-situ. In addition, the CNC-tool may form notches in the top layer 110 to indicate where outer and inner walls 210, 220 (shown in Fig. 6 and 7) should be positioned on top of the construction foundation 1000. Moreover, the CNC-tool can machine inclinations in the top layer 110 such that inclinations towards effluent outlets in showers and the like are prefabricated and need not be cast on site.

The foundation elements 100 may be used as an edge foundation element, or as a part of a complete construction foundation 1000 (shown in Fig. 6 and 7). The prefabricated foundation elements 100 may be attached to each other by an adhesive, such as a glue, or they may be fastened to each other by fastening means, such as bolts or screws, to form a construction foundation 1000 (shown in Fig. 6 and 7).

The foundation element 100 may be arranged at least partially below ground level, such that the top layer 110 is elevated above ground level and the remaining parts of the foundation element 100 are arranged below ground level. The foundation elements 100 and parts thereof presented in the figures are not in scale.

Fig. 6 shows a top view of a construction foundation 1000 comprised of four prefabricated foundation elements 100A, 100B, lOOC and 100D. A building 200 having walls 210 and inner walls 220 is arranged on top of the construction foundation 1000. Each foundation element 100 has a length L and a width W. A typical length L of the element is between 0,5 and 6 meters, preferably 1 and 5 meters, even more preferably 2 to 3 meters, and most preferred about 2.4 meters. The width W is e.g. between 1 and 15 meters, such as 2-10 meters or 6-8 meters. However, the width W may be larger than 12 meters. These dimensions are advantageous since a standard private house is usually built with a width of up to 12 meters and the dimensions are favourable when considering transportation. Foundation elements 100 of up to 3 x 12 meters will fit inside a transportation truck.

As described above, the foundation elements 100 may comprise reinforcement layers 115 along at least one side thereof and the foundation elements 100. In Fig. 6, the two end foundation elements 100A, 100D preferably each comprise three reinforcement layers 115, of which one extends along the long side facing the external side of the formed construction foundation 1000 and the remaining two reinforcement layers 115 extend along the short sides of the foundation elements 100 A, 100D. The two middle foundation elements 100B, lOOC preferably comprises reinforcement layers 115 along each short end thereof, since these edges face the external sides of the construction foundation 1000 where support for outer walls 210 (see Fig. 7) is needed.

In the uppermost foundation element 100A of Fig. 6, grooves 180 have been pre-milled in the wooden top layer 110 (not shown) to fit cables for a floor heating system. An electricity line 190 indicated by a dashed line in Fig. 6 has been arranged in the foundation elements 100B, lOOC, 100D to draw electricity through the construction foundation 1000 between inner walls 220. The pre-milled grooves 180 and the design of space for electric wires 190 are examples of how the prefabricated foundation elements 100 herein may be designed specifically for special needs in different buildings.

The foundation elements 100 are preferably mounted on the ground, such as a packed foundation bed which may be covered with an even leveling layer comprised of e.g. sand. Optionally, the foundation element(s) 100 is arranged on top of a support structure comprising a pillar or a plurality of pillars. For example, the foundation element(s) 100 is arranged on top of a pillar or a plurality of pillars above ground level. When the foundation element 100 is arranged on top of pillars, the outer envelope 150 extends to cover also the bottom of the foundation element 100 facing the pillars. For example, the sections of load bearing insulation 116 are supported by the ground or pillars and are arranged between the top layer 110 and the ground or pillars for supporting the top layer 110 and the structure or building on top of it by transferring load from the top layer 110 to said ground or pillars.

Fig. 7 shows a cross-sectional side view of a house 200 and a construction foundation 1000 made of foundation elements 100 according to one embodiment. The outer walls 210 and the inner wall 220 are arranged on the foundation element 100. Beneath each wall 210, the foundation element 100 comprises a reinforcement layer 115 arranged beneath the wooden top layers 110. The foundation element 100 in Fig. 7 further comprises edge insulation layers 120, the insulation layer 130 with a hard load bearing insulation island 116 and two installation spaces 117 comprising loose insulation 118. Beneath the inner wall 220, the foundation element comprises hard load bearing insulation 116. However, the foundation element 100 as described above or as shown in Figs 1-5 is equally applicable, as explained above.

The grooves 180 for floor heating cables or pipes are machined in the top layer 110 as shown in Fig. 7. The electricity 190 is drawn through the foundation element 100 through the first installation space 117, through the wooden top layer 110 at the desired position and further on, e.g. to a final position in a wall 210, 220 through a milled groove (not illustrated) in the top surface of the wooden top layer 110. In Fig. 7, electricity 190 is drawn through the foundation element 100. However, as described above, also water pipes, sewage pipes and ventilation may be arranged in the foundation element 100 in the same way as the electricity 190 shown in Fig. 7.

In the embodiment of Fig. 7 the foundation element 100 is provided with an inclination area 195. For example, the inclination area 195 is milled in the wooden top layer 110. For example, the inclination area 195 is connected to a hole arranged through the wooden top layer 110, said hole connecting the inclination area 195 with the installation space 160, to facilitate installation of a floor drain connected to a drain pipe in the installation space 160.

With reference to Fig. 8, a flow chart for a method 800 for forming a construction foundation 1000 using the prefabricated foundation elements 100 is shown. The method 800 comprises the steps of providing 810 the foundation elements 100 to a building site, and arranging 820 at least two prefabricated foundation elements 100 next to each other on a packed base layer or a support structure (not shown), and finally attaching 820 the foundation elements 100 to each other using an adhesive or fastening means. The method 800 is easy and enables a fast formation of a sustainable construction foundation 1000.

The prefabricated foundation element 100 disclosed herein facilitates the formation of construction foundations. Firstly, as explained and exemplified above, the degree of pre-fabrication is high, meaning that details specific to each construction may be incorporated and prefabricated in the foundation element 100. The provision of installation spaces 117 filled with loose insulation 118 maximises the insulation within the foundation element 100, and no voids are formed. Further, the hard insulation islands 116 can be arranged depending on the specific needs for different building constructions and less cutting of the hard insulation material 116 is required since the installation spaces 117 holds the MEP -installations. This results in an easy and quick mounting process of the construction foundation 1000. Since the foundation element 100 is prefabricated it can be built industrially and enjoy the advantages of optimisation and repetitive effects.

The prefabrication also decreases the risk of errors in the construction foundation, and errors in the construction foundation may be difficult, expensive and time consuming to correct. Further, since the prefabrication enables a fast mounting process, the construction foundation for a private house may be finished on less than a day, for instance during half a day. Hence, the need for weather protection is decreased.

Thirdly, the foundation elements 100 are based on wood instead of concrete, which have less negative impact on the environment and the climate. It is estimated that the wooden prefabricated foundation elements 100 give rise to a significantly lowered carbon footprint of the carbon footprint rendered by a corresponding concrete foundation.

In addition, the use of wooden materials makes the foundation element 100 much lighter than other foundation elements known in the art, and there is no need for the use of cranes or other vehicles to align and assemble the foundation elements 100. The light weight also enables several foundation elements 100 to be transported at once, since weight otherwise is a limitation during transportation.

Yet another advantage with the foundation elements 100 is that they do not require a setting and drying period, as required by concrete foundations. In some cases, the foundation cast of concrete/cement require up to as much as 3 months before the construction project can continue, and floor and/or waterproofing sheets can be arranged on top of the concrete foundation. However, once the foundation elements 100 are put into place, the construction of the building on top of the formed construction foundation 1000 may continue almost immediately, since no drying or setting time is required.

Even in the event an adhesive is used to attach foundation elements 100 together, the drying period for the adhesive is much shorter than for the setting and drying time of concrete.

Furthermore, the foundation elements 100 withstand large loads (both point loads and line loads) and may bear large buildings and constructions. For instance, the foundation elements 100 may withstand the load of a building of four stories when used in its standard design. Also, the foundation elements 100 are energy efficient, meaning that they give rise to low heat leakages and help preserve the energy within the building, and that thermal bridges are kept at a minimum level.

The foundation elements 100 are also inexpensive. An estimated calculation shows that considerable savings of the cost for the construction foundation of a private house may be saved using the foundation elements 100 disclosed herein compared to a traditional concrete cast foundation.

With reference to Fig. 9, a flow chart for a method of manufacturing the foundation element 100 is shown. The method 900 comprises the first optional step of providing 910 a top layer 100 having an upper external side and a lower internal side. Then, a reinforcement layer 115 is provided 920 on the internal side of the top layer 110, along at least one edge of the top layer 110, and at least two hard load bearing insulation islands 116 are provided on the internal side of the top layer 110, centrally of the reinforcement layer(s) 115. The at least two hard load bearing insulation islands 116 are arranged such that they form an installation space 117 between them.

Optionally, reinforcement layers 115 are provided along all edges of the top layer 110, such that the reinforcement layer 115 extends along the entire edge of the top layer 110.

Further optionally, the method comprises installing 930 at least one MEP- installation in said installation spaces 117 and filling 940 the installation spaces 117 with loose insulation material 118. Alternatively, the installation spaces 117 are first filled with the loose insulation 118 and then MEP -installations is drawn through said installation spaces 117. Since the loose insulation 118 is soft, pipes, cables and the like can be forced into the installation spaces 117 while they are stuffed with loose insulation 118. The fact that steps 930 and 940 may take place in either order is indicated by the double ended arrow in Fig. 9. Further optionally, the method 900 comprises a step of attaching 950 an edge insulation layer 120 on at least one side edge of the foundation element 100 and/or further optionally attaching 950 and outer envelope 150 on the external side of the foundation element 100. This attachment step 950 may also comprise attaching the moisture barrier layer 140 to the bottom of the foundation element 100 and/or arranging a portion of hard insulation 116b below the reinforcement layer 115, between the reinforcement layer 115 and the moisture barrier layer 140.

The method 900 may also comprise the step of transporting the foundation element 100 to a building site and placing 960 the foundation element 100 on the ground. This step may be conducted after or before performing the steps of installing 930 the MEP-installations and/or filling 940 the installation spaces 117 with loose insulation 118, which is indicated by the arrows in the flow chart in Fig. 9.

The foundation elements 100 disclosed herein are rectangular. However, the foundation element 100 may have any other suitable geometrical shape, such as a square or triangular shape. Furthermore, a private house often comprises bay windows, entrances extending from or being withdrawn from the base of the building, or rounded arced shapes. In fact, a building may have various geometrical shapes. Therefore, the edge features of the foundation element 100 being the wooden reinforcement 115, the edge insulation layer 120 and the building envelope 150 may extend partially or entirely along the circumference of the foundation element 100, independent of the shape of the foundation element 100.

Optionally, the edge features being the wooden reinforcement 115, the edge insulation layer 120 and the building envelope 150 partially extends around the circumference of the foundation element 100. For instance, if the foundation element 100 is rectangular shaped, the edge features extend along one, two or three of the four sides of the foundation element 100. For instance, if the foundation element is semi circular, the edge features may extend only along the rounded periphery of the foundation element 100. Further, a single foundation element 100 may be used to form a construction foundation 1000. In such case, the reinforcement layer 115, the reinforcement plate 117, the edge insulation layer 120, and/or the outer envelope 150 extends around the entire circumference of the foundation element 100. In the claims, the term “comprises/comprising” does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms “a”, “an”, “first”, “second” etc. do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.