Technical field The present invention concerns building elements and a method of erecting buildings using the building elements.

Background

Concrete is the most important building material in the wo rid. Buildings built out of concrete require a very strong supporting construction; there only for the sake of being able to carry the concrete's own heavy weight It has been calculated thatabout80% of the structural design of a traditional concrete building serves to carry its own weight Despite its many times disproportional weight, Ihe material has itself several important and good properties. Fb r example, it is durable, strong, non-combustible and easy to shape by casting. Cement, which is the main raw material is very energy consuming at its manufacture and releases a very large amountof CO ₂ into the atmosphere. Therefore, there is an important reason to use a concrete building engineering which takes the positive properties of the material as a starting point and minimize the negative by being able to reduce the volumetric weight by about 80%.

Today's house building offers many engineered construction solutions which use a number of different materials with different functions in the completed construction. The insulating function often causes heavy problems since these materials in price worthy applications either are tight and inflammable (for example expanded polystyrene) or non-combustible but open (mineral wool). The inflammable insulating materials are problematic already due to the inflammability, but involves also by means of its tightness a risk of moisture enclosure if the construction is notthoroughly designed and executed. The open insulating materials also require cost increasing constructions for mounting and moisture protection and are practically incompatible with a stone house. Generally, the building methods of today are based on a multi material technology where different types of materials are used in collaboration and are expected to solve different functions when they are mounted together. This increases the demands on the engineer since it concerns complicated relationships which are difficult to calculate. At the same time, it is expected from the building industry to develop both more cost effective methods as well as energy saving materials and constructions.

The reasons for many building problems are often the result of unsuitable material combinations which cause the final constructed structure to not function in the proper way together. Additionally, a non-industrial working method with long production time at the building site causes a risk for the building materials to be exposed to rain and chill during the long mounting time. The costs for heating and cooling, respectively, of the indoor air increases dramatically today at the same time as the society wishes to decrease unnecessary energy due to environmental considerations. It is therefore of utmost importance to provide a both effective and fireproof insulation that does not risk the build up of moisture and mould in the construction, but instead allows the walls of the building to breath. The modem air-tight houses, with the aim of providing an effective insulation in order to save energy, has instead caused the build up of moisture in the construction and caused mould problems. This problem had created not only an economic problem for the builder, but has also led to public health concerns.

Building blocks of lightweight concrete having a volumetric weight between 400 - 800 kg/ m ³ have been produced since 1930. The first lightweight concrete was based on alum slate. However, in the 1970s the inexpediency to use this material was called attention to since it comprises uranium which emits radon, which led to a stop in production of lightweight concrete based on alum slate in 1975. After that lightweight concrete has subsequently been produced outof, for example, finely ground sandstone, cement and lime, which are forced to expand in an autoclave by means of a gas development caused by the heating of aluminium powder in the formula. These building blocks are generally produced in small entities which are stacked and joined at the working site similar to the building of a brick wall. The capillary suction force of these materials is so strong thatthey can absorb substantial amounts of moisture, decreasing the insulating value of the material, depending on how they are installed.

A method of mixing in light expanded plastic particles of expanded polystyrene (EFS) in the cement mix was introduced in the 1950s and has gained some usage as lightweight ballast in concrete of higher volumetric weight, about 1000 kg/ m ³ or more, which in itself is however a considerable reduction in weight from the normal density of concrete of about2400 kg/ m ³ . The problem has been to achieve a homogeneous mix since the expanded plastic spheres float in the water mix. This problem may be overcome today and treated EFS-particles for this purpose may be bought on the market This development has also made possible the creation of the present invention.

Summary of the invention

The object of the invention is to provide a simplified, quality assured, cost effective, resource effective, environmentally friendly, non-combustible, high strength self-supporting, vapour diffusible building system based on cement or other mainly inorganic material but with low volumetric weight which thereby also gives the material an in-built insulation. Another object is to provide an "all- in-one" material in the shape of manageable and connectable building elements which will allow for a quick and quality assured construction at the building site. Using the method according to the invention the raising of a building of a normal sized house takes about three days, instead of about three months typically required with traditional building methods.

The building element of the invention is made of a building compound, which comprises highly insulating EFS-particles, or particles of other insulating material or medium, mixed into a cement mix or other mainly mineral based building compound which then cures when it reacts with water. The particles give by their mixing 4n into the wet building compound the resulting cured lightweight material a volumetric weight of about 50 - 800 kg/ m ³ , the compression strength is more than 0,5 MRi and the coefficient of thermal conductivity λ is less than 0,15. The building element according to the invention shows at least one integrated form fit, which is connectable with a form fit of an adjacent element Freferably, the volumetric weight is 300-600 kg/ m ³ of the building element and mostpreferred 400-500 kg/ m ³ . Freferably, the compression strength is more than 1,0 MFk and mostpreferred more than 2,0 MFk. Freferably, the coefficient of thermal conductivity λ is less than 0,12 and mostpreferred less than 0,10.

The definition of form fit is each element is integrated with a profile or recess that at assemblage is used for positioning or locking the element against other contacting building elements. This should also include conceivable solutions with separate details which are fitted into a form fitof a firstbuilding element in order to then at mounting of a second building element, the separate detail/ details be fitted into the form fit of the second building element Fbr example each building element may be provided with a lengthwise recess into which one or more leafs or the like is entered into each recess of the building element at assemblage, resembling of tongue and groove assembly. The overall inventive idea is to create a positioning or locking of building elements, as a building system, where the person skilled in the art may design the positioning or locking in a desired way in different emb o diments o f the inventio n.

Thanks to the form fits of the building elements it is provided a type of locking of adjacent building elements which prevent displacement in the construction, which may cause cracks in the elements or at their joints. This could happen at settling, ground vibrations, pressure waves, blastings and earth quakes.

The insulating particles are moisture-proof and have preferably a volumetric weight which is less than 50 kg/ m ³ , more preferably less than 30 kg/ m ³ . Most preferred the particles have a volumetric weight up to 15 kg/ m ³ . The volumetric weight is generally in inverse proportion to the coefficient of thermal conductivity λ, i.e. the lower volumetric weight the higher insulating value. The desired volumetric weightofthe end product may be decided according to the amount of particles that are mixed in Freferably a mix is used comprising at least 50 percent by volume of insulating particles of expanded polystyrene (EFS) with closed cells or other non moisture absorbing material or medium with a volumetric weight not more than 30 kg/ m ³ . Also expanding agents, air or other media may be added to the mix.

The insulating particles may have for example graphite or aluminium admixture for increased insulating performance. The insulating particles may have different fractions of different sizes for enhanced coefficient of fullness. Without different fractions airspace is formed between the concrete-covered and against each other adhering particles which thus gives the mix a lower insulating value, i.e. coefficient of thermal conductivity λ. The insulating particles may have every shape but are preferably spherical to achieve optimum strength in the concrete shell which is formed around each particle and which adhere against adjacent shell provided particles. R>r enhanced strength in the cement mix and thus in the concrete shells, particles of glass or another aggregate element may be added. R>r example two fractions may be mixed where preferably the first fraction has a size up to 1,5 mm and the second fraction preferably has a size between 1 ,5 mm and 3 mm. The first fraction may be 20 % and the second fraction may be 80% as an example.

Fbr this invention, a suitable and in this way produced material mix may achieve: a) a coefficient of thermal conductivity λ of less than 0,15, preferably about 0,06-0,12, b) a compression strength of at least 0,5 MRi, preferably at least 1,0 MRi, c) a vapour diffusion resistance between 10 000 - 400 000 s/ m, preferably between 10 000 - 100 000 s/ m, mostpreferred between 10 000 - 30 000 s/ m.

A building element according to an embodiment of the invention has a wall fo undatio n shape with a fo rm fit at an upper po rtio n o f the wall fo undatio n element at use. The wall foundation element is connectable with a form fit of a wall element, where the form fit is situated at the lower portion of the wall element at use. The wall foundation element is preferably also connectable to one or more adjacent wall foundation elements by means of form fitting.

Iteinforcementis preferably cast into the wall foundation element and at least one attachment means extends outof the wall foundation element at the side that in use faces inwards the building. Referably the reinforcement and the attachment means are connected. The attachment means are used for attachment of reinforcement for the foundation which is cast after the wall foundations have been positioned in their desired location.

Another building element according to an embodiment of the invention has a wall shape with at least one form fit situated at a lower portion of the wall element in use. The wall element is connectable with a form fit of a wall foundation element, where the form fit is situated at the upper portion of the wall foundation element in use.

The wall element has preferably at least one form fit at its vertical end portions in use, whereby the wall element is connectable with a form fit of one or more adjacent wall elements. These form fits may be situated at the side surfaces and/ or end surfaces at the vertical end portions of the wall elements.

The wall element has preferably at least one form fit situated in an upper portion of the wall element in use. In such a way it is connectable with atleastone form fit of a floor joists element or a roof joists element

A further building element according to an embodiment of the invention has a floor joists shape or roof joists shape with at least one form fit The floor joists element or roof joists element is connectable with a form fit of one or more wall elements, where the form fit is situated at the upper portion of the wall elements in use.

The floor joists element has preferably at least one form fit which is connectable with a form fit of one or more wall elements, whose form fits are situated at their lower portions in use, for providing floor levels above the first

A still further building element according to an embodiment of the invention has infill shape, i.e. it is intended to be mounted in the open space between raised vertical elements, such as inner walls, and floor joists in order to form the outer wall. The infill element has atleastone form fit suitable for the space formed by the vertical elements and the floor joists and shows a surrounding protrusion for contact against floor joists and vertical elements.

Referably the infill elements have atleastone protruding lip which extends outside the surrounding protrusion along one or two adjacent sides for overlapping a junction between adjacent infill elements in mounted position. In such a way the heat leakage and downdraughtin the junction between the infill elements will be minimized. Referably both the protrusion and lip integrated cast of the same material as the rest portion of the infill element

The form fits are preferably concave and correspondingly convex along the whole length of the building elements in order to provide an overlap or displacement inside the junction which radically diminish or prevent heat leakage and do wndraught through the junction and mutually locks the parts of the construction. M order to further minimize the heat leakage and do wndraught a sealing may be provided on the form fits, for example a sealing compound. Referably the wall foundation elements are provided with convex form fits and the wall elements are provided with concave form fits in their lower portions in order to minimize the risk that rain water penetrates and stays in the junction, especially during the actual building process.

M the building elements of the invention means are possible to cast into the elements. It could for example be reinforcements, attachment means so that screws may attach properly in the building elements, frames for doors and windows, whole windows or doors, conduits for electricity or water supply and sewer systems and so on.

The reinforcement may be a, for each construction suitable, one, two or three dimensionaUy shaped reinforcement structure, of for example metal net, in-cast in the element so the element can withstand also very high loads vertically as well as horizontally. The reinforcement structures may also be in-cast angled, trapezoid or in other form Except as a reinforcement of the building element in its use in building constructions for example double reinforcement, i.e. two reinforcement structures in the same building element, may be an advantage in connection with the production of the building element in order to prevent the building element to wring during the drying after the casting.

The building elements according to the invention make up a building system where at first hand the wall foundation elements and the wall elements are comprised but preferably also the floor joists elements, roof joists elements and most preferred also the infill elements are comprised. The foundation is preferably cast with the same type of building compound as used for the building elements.

The inventive method of erecting buildings by means of building elements according to the invention comprises the step of lay out prefabricated die-cast wall foundation elements on a levelled, stable and drained surface, onto which wall elements are connected by means of the form fit

Referably prefabricated die-cast floor joists or prefabricated roof joists are connected by means ofform fitatthe upper portion of the wall elements. If more than one floor level is desired, prefabricated die-cast wall elements are connected, at their lower portion, by means of form fit with floor joists, attheir outer portions, in order to provided floor levels above the first

There are two different modes of procedure for raising a house. Either the outer walls and structural load carrying inner walls and floor joists are raised to a desired height and are finished with fitting the roof joists. Or the structural load carrying inner walls and floor joists are raised to a desired height and are finished with fitting of the roof joists. Thereafter, infill elements are mounted forming the outer walls. AU the building elements are produced in a factory. The foundation is cast with building compound according to the invention between the wall foundations, preferably after that the roof joists have been mounted, i.e. inside its own house only after the building is raised, which means that all parts of the building are cast and cured under controlled conditions during all times of the year.

On the outer wall of the building preferably a layer of plaster of a mineral base coat having a capillary suction force which is higher than the capillary suction force of the wall element The outside layer of plaster serves partially as reinforcement, smoothing, colour decor layer and moisture absorbent/ moisture regulator which guarantees that the insulating value of the wall is maintained since the pores of the wall element always are dry. The layer of mineral base coat plaster may be provided prefabricated in a factory or at the building site. As an alternative, a panel wall of, for example wood, may be mounted on the outside of the wall element with air space in between.

With this building system based on light weight elements according to the invention a row of advantages are achieved in relation to known art I) A, in its most complete embodiment, uniform material concept for all of the parts of the building: the foundation and wall foundation elements, wall elements, floor joists elements, roof joists element and infill elements may be made of the same type of material with the same insulating value, because no down drafts will arise in the junctions between the different building elements. At least the outer wall elements ought to be of the same material.

2) The building elements are non-combustible.

3) The building elements are self supported.

4) The building elements are vapour diffusible (breathe).

5) The building elements are insulating. 6) Since the components/ building elements of the building system are prefabricated in a controlled factory environment the environmental condition problems that otherwise apply on a building site are avoided for what re a son the production efficiency and the quality will be much higher and more even.

Thanks to the form fits the raising of buildings will be very much facilitated which means a time saving at the same time as it guarantees an exact mounting.

Short description of the drawings

The present invention will be described in more detail during referral to the attached drawings, in which;

Hg. 1 shows a building element according to the present invention which has a wall foundation shape in perspective, partly broken off,

Hg. 2 shows a building element according to the present invention which has a wall shape in perspective, partly broken off, Hg. 3 shows a wall element according to the present invention from one side,

Hg. 4 shows a wall element according to the present invention from above, partly broken off, Hg. 5 shows a building element according to the present invention which has a floor joist shape from the side together with a wall element and a wall foundation element,

Hg. 6 shows a building element according to the present invention which has a roof joist shape from the side together with a wall element,

Hg. 7 shows the roof joists element of Hg. 6 with an extra locking,

Hg. 8 shows a building element according to the present invention which has an infill shape in cross section,

Hg. 9 shows the infill element of Hg. 8 from the inside,

Hg. 10 shows a variantof the infill element of Hg. 8 in cross section,

Hg. 11 shows the infill element of Hg. 10 from the inside,

Hg. 12 shows a wall foundation element according to the invention in cross section with reinforcement and attachment means,

Hg. 13 shows six wall foundation elements with attached reinforcement in between, Hg. 14 shows a building element with reinforcement in cross section,

Hg. 15 shows a building element with double reinforcement in cross section,

Hg. 16 shows an embodiment of a form fit,

Hg. 17 shows another embodiment of a form fit,

Hg. 18 shows an outer wall during raising from the outside of a future building, and

Hg. 19 shows a mounted infill element from the inside of a future building.

Detailed description of preferred embodiments of the invention The building elements of the invention are prefabricated in a factory, i.e. wall foundation element 1, wall element 3 , floor joists element4, roof joists elementδ and infill elements 7, 10. The building elements are die-cast of a building compound, based on for example cement or other mainly inorganic material, which cures in a water mix, with mixing in of particles of expanded polystyrene (EPS) having closed cells or other insulating material or medium. Referably the prefabricated elements have a size of up to 3 x 14 m, a thickness of 100400 mm and a volumetric weight of 300-600 kg/ m ³ . The compression strength of the building element is preferably atleast l ,0 MRi and the coefficient of thermal conductivity λ less than 0,15.

The insulating particles are moisture-proof and have preferably a volumetric weight which is less than 50 kg/ m ³ , more preferably less than 30 kg/ m ³ . Most preferred the particles have a volumetric weight up to 15 kg/ m ³ . The volumetric weight is generally in inverse proportion to the coefficientof thermal conductivity λ, i.e. the lower volumetric weight the higher insulating value. The desired volumetric weightofthe end product may be decided according to the amount of particles that are mixed in. Referably a mix is used comprising at least 50 percent by volume of insulating particles of expanded polystyrene (EF) with closed cells or other non moisture absorbing material or medium with a volumetric weight not more than 30 kg/ m ³ . Also expanding agents, air or other media may be added to the mix.

The insulating particles may have for example graphite or aluminium admixture for increased insulating performance. The insulating particles may have different fractions of different sizes for enhanced coefficient of fullness. Without different fractions airspace is formed between the concrete-covered and against each other adhering particles which thus gives the mix a lower insulating value, i.e. coefficient of thermal conductivity λ. The insulating particles may have every shape but are preferably spherical to achieve optimum strength in the concrete shell which is formed around each particle and which adhere against adjacent shell provided particles. R>r example two fractions may be mixed where preferably the first fraction has a size up to 1,5 mm and the second fraction preferably has a size between 1,5 mm and 3 mm. The first fraction may be 20 % and the second fraction may be 80% as an example. R>r enhanced strength in the cement nix and thus in the concrete shells, for example particles of glass may be added.

The building elements have a form fit 2 which fit with an adjacent building element The form fits 2 are preferably concave and correspondingly convex along the whole length of the building elements in order to provide an overlap or displacement inside the junction which radically diminish or prevent heat leakage and do wndraught through the junction. M order to further minimize the heat leakage and do wndraught a sealing may be provided on the form fits, for example a sealing compound (not shown). The form fit provides a locking and reinforcement of the construction which prevent cracks to arise due to settlings, ground vibrations, pressure waves, blastings and earth quakes.

M Hg. 1 a first building element according to the invention is shown having a wall foundation shape 1. Referably the wall foundation elements 1 are provided with convex form fits 2 and the wall elements 3 are provided with concave form fits 2 in their lower portions in order to prevent the risk that rain water will penetrate and stay inside the junction, especially during the actual building process, se Hg. 1, 2 and 5. The wall foundation element may be as wide as the wall element 3 or wider than a wall element 3 , for example 50-70% wider and has preferably downwards sloping surfaces on that part of the upper portions which extends outside the thickness of the wall element The extra width stabilise the wall foundation element 1 and minimise the possibility for the ground frost to penetrate into the junction between the wall foundation element 1 and the wall element 3 and the sloping surfaces make the rain water to run off the wall foundation elements 1. The wall foundation elements 1 should also be provided with form fits 2 at their end portions for connection with adjacent wall foundation elements 1, see for example Hg. 13 where the wall foundation elements lock each other in position.

M Hg. 2 a building element according to the invention is shown having a wall shape 3. Fb r clarity sake only two form fits 2 in the upper and lower edge have been shown in the figure. Li Hg. 3 two concave and two convex form fits 2 are shown. The wall element 3 in Hg. 4 is shown from above and is provided with two form fits on both sides at its vertical end portion and along the end surface and along the upper surface. M such a way a wall element 3 may be connected to an adjacent element, such as another wall element 3 , wall foundation element 1, floor joists 4 or roof joists 5, by means of the form fits 2.

M Hg. 5 it is shown how a building element having a floor joists shape 4 may look like. M this case it is shown together with a further floor joists element 4, two wall elements 3 and a wall foundation element 1. All elements are connected by means of the form fits 2, which provide a locking between the elements.

A building element according to the invention having a roof joists shape 5 is shown in Hg. 6. Two roof joists elements 5 cooperate and rest on wall elements 3. If extra locking is desired, mountings 6 may for example be mounted between the wall element 3 and the roof joists element 5 and/ or between adjacent roof joists elements 5, see Hg. 7, at desired distances.

M Hg. 8 and 9 a building element according to the invention is shown having an infill shape 7. There are two different modes of procedure for raising a building. Either the outer walls 3 and structural load carrying inner walls 3 and floor joists 4 are raised to a desired height and are finished with fitting of the roof joists 5.

Or the structural load carrying inner walls 3 and floor joists 4 are raised to a desired height and are finished with fitting of the roof joists 5. Thereafter, infill elements 7 are mounted forming the outer walls.

ff the inner walls 3 are mounted on the wall foundation elements 1 and floor joists elements 4 are raised to desired height and the roof joists 5 thereafter is fitted, the outer walls may be formed by mounting infill elements 7 in the spaces which are formed between the floor joists elements 4 and the vertical elements, such as the inner wall elements 3. The inside 8 of the infill elements 7 fills the space between the wall elements 3 and the floor joists elements 4 while a surrounding protrusion 9 contacts the wall elements 3 and floor joists elements 4. The protrusion 9 preferably covers half of the width of the wall elements 3 and floor joists elements 4. M Hg. 10 and 11 a variantof an infill element 10 is shown which creates an overlap of the junctions between the adjacent each other mounted infill elements

10 since one or two sides are provided with a lip 11 which covers the junctions along the lip provided sides and abuts against the sides 12 of the protrusions 9 of the adjacent infill elements 10. Referably are both the protrusion 9 and the lip

11 integrated cast of the same material as the remaining portion of the infill element 7, 10. The infill element 7, 10 has additionally preferably a mounting or means 17 for locking to a floor joists 4 and vertical elements 3, respectively, in order to be fixed in its mounted position, see Hg. 19.

M Hg. 18 it is shown a started build up of an outer wall by means of infill elements 10 which are fitted in between vertical elements 3 and floor joists 4 and overlap over the junctions between adjacent infill elements 10 with at least one lip 11.

It is possible to already atthe production of the building elements to cast in reinforcements, frames for doors and windows as well as conduits for electricity and water supply and sewage systems, anchoring and other preparations. M order to facilitate later mounting of for example suspension mountings in the ready built building, plates of for example wood or expanded metal be cast into the building elements, wherein for example screws may be fixed in a secure way.

M Hg. 12 a reinforcement cage 13 is castinto a wall foundation element 1. Fbrm the reinforcement cage 13 an attachment means 14 extends which protrudes out from the side of the wall foundation element 1 at that side which in a mounted position faces inwards the building. M these attachment means 14 reinforcement may be connected between the wall foundation elements 1 in order to form the reinforcement for the later foundation.

The reinforcement may be a, for each construction suitable, one, two or three dimensionally shaped reinforcement structure, of for example metal net, in-cast in the element so the element can withstand also very high loads vertically as well as horizontally. The reinforcement structures may also be in-cast angled, trapezoid or in other form. M Hg. 14 a building elementis shown from the end in cross section with a zick-zack shaped reinforcement structure 16.

Except as a reinforcement of the building element in its use in building constructions for example double reinforcement, i.e. two reinforcement structures 16 in the same building element as shown in Hg. 15 , may be an advantage in connection with the production of the building element in order to prevent the building element to warp during the drying after the casting. The in-cast reinforcement structures 16 may also serve as attachment for, for example in combination with an in-cast and in the reinforcement structure welded metal plate, attachment means of the building elements. When using anchorage reinforcement, a hole in the building element may be drilled when mounting at for example a pre marked position and then may for example so called chemical anchorage be attached. Anchoring by means of chemical anchorage may for example be used for anchoring of infill elements 7, 10. As an example a metal thread having a diameter of 6-8 mm may be assembled into a net with for example openings having a size of a square decimetre. The nets may be shaped or pressed into desired shape.

The building elements may be produced in any desired design according to the geometry of a casting tool, taking practical limitations in consideration such as strength, transportation limitations etc. The building elements may for example be castbent, having any desired diameter, for the building of archs, towers, extensions and rounded gables or with any desired topographical surface profile in order to provide a living wall surface. The casting forms for the element production may be made of, for example, metal, glass reinforced plastic or other suitable material. As the person skilled in the art understands, the form fits 2 may be positioned at any desired portion of the inventive elements due to desired fit in position in the future building.

According to the inventive method the wall foundation elements 1 are positioned and levelled around or inside the future prepared foundation The wall foundation elements 1 show preferably a convex form fit 2 against the concave form fit 2 of the wall elements 3. The wall elements 3, for example having the size 3x14 m, is preferably positioned upright on its edge on top of the wall foundation elements 1 and are stacked horizontally for higher floor-to^loor height before connection to the floor joists elements 4 or roof joists elements 5 are made. The wall elements 3 may also be used in a vertical upright position The concave form fit 2 of the wall element 3 fits with dimensional accuracy and stable in the form fit 2 of the wall foundation element 1.

Floor joists elements 4 as well as roof joists elements 5 lie directly on the wall elements 3 and are connected with a similar form fit system as the wall elements

3 to the wall foundation elements 1. Since the floor joists elements 4 may have the same insulating value as the as the walls 3, a floor joists element 4 may pass all the way out to the outer surface of the outer wall, or even protrude outside of the outer wall in order to provide a balcony floor, without causing a down draught in the construction, which would be the case if the floor joists element would notbe insulated (not shown). This is normally a great problem concerning balcony constructions. At the top of the roof joists elements 5, profiles may be cast into the element for simple mounting of desired roof material. M a similar way, the wall elements may be provided with profiles for simple mounting of for example panels.

The foundation is preferably cast with a building compound according to the invention between the laid out wall foundation elements, preferably in house in its own building after the building is erected, which means that all parts of the building has been cast and cured under controlled environment during all seasons of the year.

On the outer wall of the building preferably a layer of plaster is provided of mineral base coat having a capillary suction force which is higher than the capillary suction force of the wall element The outside layer of mineral wall plaster serves partially as reinforcement, smoothing, colour decor layer and moisture absorbent/ moisture regulator which guarantee that the insulating value of the wall is maintained since the pores of the wall element always are dry. The layer of mineral base coat plaster may be provided prefabricated in a factory or at the building site. As an alternative a panel wall of for example wood may be mounted on the outside of the wall element with air space in between.

As previously defined, the form fit is every integrated profile or recess that at connection is used for positioning or locking two against each other adjacent building elements. This should also encompass conceivable solutions with separate details which are fitted into a form fit of a first building element and then at mounting of a second building element, the one or more separate details shall fit into the form fitof the second building element R>r example, each building element 3 may be provided with a lengthwise recess 2 into which one or several blades 17 or similar are entered in each recess 2 of each building element during connection, similar to tongue and groove-connections, see Hg. 16.

The overall inventive idea is to create a positioning or locking of building elements, as a building system, where the skilled person in the art may design the positioning or locking in a desired way in different embodiments of the invention. It is also conceivable to design the form fit 2 as is shown in Hg. 17 where the building elements are provided with recesses 18 wherein pins 19 is fitted for connection of the two adjacent building elements.