BACKGROUND TECHNICS Bulding elements manufactured in cement-bound wood wool have been known for a very long time. The material is used preferably in the form of elongated slabs of relatively little thickness for dressing of walls, in floor frame work and as roof slabs. Building elements of cement-bound wood wool are preferably used as heat insulating elements without any real structural function.

Cement-bound wood wool appeared to be very environment friendly and does not emit toxic substances which may cause allergies or the like. Cement-bound wood wool also may be recycled in form of energy by burning without any outlet of toxic substances to the nature which is of importance in future demolition of a building which is built from material like this.

Building elements of cement-bound wood wool are a substitute for other types of building elements as e.g.

elements of light-weight concrete which in certain cases may emit radon or building elements which contain resin glue of different kinds and which may emit toxic substances as e.g. formaldehyde.

DESCRIPTION OF THE INVENTION The object of the present invention is to achieve a building system according to the preamble in which building elements of cement-bound wood wool are used as structural elements in walls, floors and roofs,

preferably ceilings. The object is achieved by means of reinforcing irons which are arranged at least in the walls and extending at least along two adjacent building elements in a space between these elements. The building system according to the invention is characterized in that reinforcing bars are arranged projecting a short distance into two adjacent building elements in a distance from each other along facing sides or edges and joined by the reinforcing irons.

Preferably the reinforcing bars are firmly joined with the reinforcing irons before being placed between the building elements which however are provided with holes for the reinforcing bars to be taken up within the reinforcing. When setting up e.g. two vertical build- ing elements in the shape of wall slabs a first wall slab is fixed in the desired position in the conventional way e.g. by means of wooden bars or the like whereupon the reinforcing irons complete with the reinforcing bars are attached by projecting the reinforcing bars into previously made holes in the long side of the first wall element and whereupon a second wall element is moved towards the first wall element so that the reinforcing bars are pressed into the second wall element as well.

Preferably the wall elements are provided with grooves along at least one long side and possibly along at least one short side as well which gives space for vertical or horizontal reinforcing irons. Preferably the wall elements, the reinforcing irons complete with the reinforcing bars are fixed by means of liquid concrete which is fed into the space between the wall elements.

When the concrete has hardened, together with the reinforcing irons it constitutes a pillar with structural function.

Reinforcing irons with advantage may be arranged in walls, in floor frame work as well as in ceilings, the different reinforcing irons being connected along the corners and the upper and lower wall sides of the build-

ing. In this way the reinforcing irons complete with the reinforcing bars constitute a "cage" which partly keep the building together and partly constitute structural elements together with concrete in the walls. The "cage" constituted of the reinforcing irons may be reinforced furthermore by the connection with reinforcing netting which then is arranged at least on one broad side of the building elements and which preferably extends unbroken over several adjacent building elements in floors, walls and ceilings. The reinforcing netting is preferably cast into a concrete layer of the floor frame work and coated with plaster on the other surfaces in the building. The reinforcing netting may be arranged both on the inside and on the outside of the building.

It lies within the scope of the invention to connect the reinforcing irons, the reinforcing bars and the reinforcing netting in several various ways e.g. by welding or by conventional tying by means of tying wire. This tying may be done either in advance in the form of a prefabricated reinforcement or in situ when assembling. It also lies within the scope of the invention to produce the notches or grooves in the building elements in situ when assembling. In this way freedom of choice is gained concerning the placing of wall elements in interior walls and the connection of these to elements in external walls.

Further features and characteristics concerning the building system according to the invention are evident from the description to the drawings subsequently and from the claims.

DESCRIPTION TO THE DRAWINGS The invention is described subsequently as an example of an embodiment in connection with the enclosed drawings.

Figs. 1 and 2 show a wall slab according to the invention seen from a plane side or from a long side.

Fig. 3 shows the wall slab according to figs. 1

and 2 seen from above on fig. 1.

Fig. 4 shows a wall slab in an alternative embodiment seen in the same view as in fig. 3.

Fig. 5 shows a floor slab seen from a short side.

Fig. 6 shows a roof slab seen from a short side.

Fig. 7 shows a section of a building built from the slabs which are part of the building system according to the invention.

Fig. 8 shows separately reinforcing irons which keep the building slabs together in the building system according to the invention.

Part of the building system according to the invention as shown in figs. 1-3 is a rectangular wall slab 1 manufactered from cement-bound wood wool compris- ing two long sides 1.1, each showing a groove 1.2 extending centrally in each long side 1.1, an upper short side 1.3 with a likewise central groove 1.4 and a lower short side 1.5. The wall slab 1 shown in fig. 4 is intended for the formation of corners or the connection of transversal walls inside the building concerned and shows a groove 1.2 in one of the long sides and a groove 1.6 in one of the plane sides. The floor slab 2 as shown in fig. 5 shows long sides 2.1 with notches 2.2 extending along the long sides 2.1 along one and the same side of the floor slab 2. The roof slab 3 as shown in fig. 6 shows a completely rectangular cross section apart from small bevels 4 which are arranged along two long sides 3.1 along one and the same side of the roof slab 3. As shown in fig. 3 and 4 the wall slab 1, too, is provided with corresponding bevels 4.

The slabs 1, 2, 3 which ar part of the building system may be assembled to a building as shown in fig. 7.

Wall slabs 1 are placed on a bedding of floor slabs 2 with their lower short sides 1.5 resting on one of the plane sides of the floor slabs 2. In this case the floor slabs 2 constitute a floor frame work. Vertical

reinforced irons 5 are arranged within the closed space constituted by the notches 1.2 in two long sides 1.1 of the wall slabs 1 bearing against each other. The vertical reinforcing irons 5 comprise a number of reinforcing bars 5.1 which extend at right angles to the respective long side 1.1 and a bit into the respective wall slab 1 and which are connected with an reinforcement wire 5.2 running in the hollow space constituted by the notches 1.2 in the long sides 1.1. The reinforcing irons 5 are fixed when the wall slabs 1 have been joined together with liquid concrete which is fed from above into the hollow space between the long sides 1.1. When the concrete has hardened it constitutes together with the reinforcing irons a pillar which has the ability to bear a vertical load.

The reinforcement wire 5.2 extends a bit downwards in the groove between two floor slabs 2 to connect there with horizontal reinforcing irons 6 which extend within the notches 2.2 in the groove between two floor slabs. The reinforcement wire 5 extends also a bit uppwards in the joint between two roof slabs 3 which are arranged resting on the upper short side 1.3 of the respective wall slab 1 and connects there with horizontal irons 7 which run in the groove 1.4 in the respective upper short side 1.3 of the wall slabs 1. The horizontal reinforcing irons 7 comprise a number of reinforcing bars 7.1 which extend at right angles to the respective upper short side 1.3 and a bit into the respective wall slab 1 and the roof slab 3 resting on it and which are connected with a reinforcing wire 7.2 running in the hollow space formed by the groove 1.4 in the upper short sides 1.3.

Vertical reinforcing irons 5 are also arranged in the hollow space formed of the groove 1.6 in the alternative embodiment of the wall slab shown in fig. 4 and which is used to form a corner in the building concerned.

The vertical reinforcing irons 5 together with the reinforcing irons 6 in the floor slabs 2 and the

horizontal reinforcing irons 7 form a cage-like construction in which the wall slabs 1, the floor slabs 2 and the roof slabs 3 are kept together to a mainly closed space. To reinforce this construction furthermore nettings may be arranged along all the surfaces in the construction but preferably only on its inside. Such a netting 8 is shown in fig. 7 where it is cast into a concrete layer 9 which constitutes the floor of the building. On wall slabs 1 and roof slabs 3 such a netting may be covered by a lime plaster material which is not shown in the figures. The reinforcing netting 8 also may be connected with the reinforcing irons 5, 7 and the reinforcing irons 6 and reinforce the strength of the construction furthermore.

The construction of the building which includes the above mentioned slabs and the reinforcing may be provided with rafters and roofs resting on the wall slabs and in particular on the reinforced concrete pillars which are arranged between the wall slabs and with doors and windows and an external coating. This is not shown in the figures either.

The building elements according to the invention may also show more holes, preferably through holes which extends between opposite long sides or short sides for the attachment off additional reinforcement, e.g.

reinforcing iron. The holes may also be lined with cases preferably of cardboard of a dimension which allows liquid concrete to be fed into those holes and form structural pillars and beams of reinforced concrete.

Even if building elements manufactured of cement-bound wood wool are preferable in building constructions according to the invention the building elements may be manufactured of other materials as e.g.

light concrete (gas concrete) which may be connected by means of the suggested reinforcing.