The invention concerns a building element of the type described in the introduction to the main claim for masonry/walls particularly in detached and terraced houses and as outer walls in agricultural outbuildings, and also in industrial and business premises, where among other things it functions as the primary load-carrying system for low buildings.

Concrete building elements with insulation are known in use. They are strong materials which at the same time provide insulation. These types of building elements are often called insulation blocks.

DE 2 756 820 and AU 360 724 describe concrete elements with a core of an insulating material. They will provide satisfactory insulation in the cross section of the wall that is insulated. However, a thermal bridge will be formed at the end walls in the blocks, which will reduce the overall insulation ability considerably. The same will occur with the concrete construction shown in SE 40 932', ^" which is also not based on prefabricated elements. SE 131 945 describes a building element with a core of an insulating material, where the end walls are shortened so that there will be a cavity in the finished wall. This partly solves the thermal bridge problem, but greatly reduces the mechanical strength. A particular objective with the present invention is to produce a building element that gives masonry/wails that can withstand relatively large vertical and lateral loads, good heat insulation, and which is particularly suited for applications such as fire walls and other walls where fire resistance is important.

Another objective is that the building element is to be made so that it is not to be difficult to drill holes through it for electric cable pipes and water pipes. The elements are to relatively easy to handle and have provide good attachment for the fittings and attachments that are normal for brick walls.

The main objective can be met by a building element designed in accordance with the characterizing part of Claim 1. Other features are presented in the subsidiary claims. A favourable combination of elements of recognized welltried materials has resulted in an insulation block with relatively high vertical and lateral loadcarrying ability. This is the result of using side members of high strength concrete and end walls of lightweight concrete with relatively good mechanical characteristics. The end walls with these characteristics act as strong bonds/ties, and with their relatively close location in the finished wall this means that they connect the two side members/skin in a very efficient manner.

Another feature is that the insulation block in the present invention contains mineral wool, which is an insulation material with extreme good heat insulation properties that is incombustible/flame resistant; the nonflammable feature is a great advantage over other known insulation blocks that contain foamed plastics. The present invention also has designed a building element that is constructed for the easy drilling of holes for electric cable pipes and water pipes since such holes can be made through the end walls of lightweight concrete in the joints between elements. Even though the insulation block has concrete side members, which have relatively high specific weight in relation to lightweight concrete, they will nevertheless be easy to handle. This is because the side member can be relatively thin due to the bonding effect of the end walls in the finished wall, and the high compressive strength of concrete in the end walls. This means that the weight can be kept low and the final weight of the block makes it easy to handle.

With 5 cm thick side members and end walls and 15 cm of mineral wool insulation, the insulation block according to the present invention should have a k-value of about 0.3, measured with the normal units.

The following describes the invention in more detail with reference to the accompanying drawings, where fig. 1 shows a standard design of a building element in accordance with the present invention in horizontal cross-section as it would stand/lie in a finished wall, fig. 2 shows a design of a building element in accordance with the present invention as a facing - also in horizontal cross-section, ^* ' fig. 3 shows a top perspective of a symmetrical half of the design in Fig. 1, and fig. 4 shows a lateral perspective of the design in fig. 1.

A building element or insulation block is shown in fig. 1, this has massive end walls 1, 2 of lightweight concrete with pumice or clinker as aggregate. Between the end walls there are side members 3, 4 of massive concrete, i.e. normal concrete, with finely-grained sand as aggregate. There is an insulation core, or insulation unit 5 made of mineral wool in the cavity inside the block. The side members 3, 4 and the end walls 1, 2 are cast together so that the end walls 1, 2 act as effective bonds/ties between the inner a d outer sides of the finished wall components/side members or skin.

The end walls 1 ,2 of lightweight concrete can. ave precast reinforcement that apart from reinforcing the wall can also strengthen the connections to the side members. This reinforcement is not however necessary partly because the end walls will/may be relatively thick and partly because the contact surface between the end walls and the side members should be sufficiently large to provide a strong connection between them. Such reinforcement could also be an obstacle for the drilling of holes for electric cable pipes or water pipes.

As mentioned, the insulation block according to' the present invention will meet numerous functions, requirements or stipulations. Irrespective of whether the block is used in areas of walls between supports and floor dividers or used as the primary load-carrying system in a building, it

can as shown in fig. 2 have a surface treatment 6 on the facing combined with grooved recesses 7, 8 on the facing side 6. The grooved recesses 7, 8 are particulary designed to provide an undersurface for the mortar in the connecting joints between two adjoining blocks. The surface treatment on the facing can be of the same material as the end walls 1, 2 or the side members 3, 4 but this is considered improbable in most cases.

Because of the reduction in the thickness of the side member that is permitted by the end walls acting as effective bonds/ties, the joint reinforcement should be of steel rods. As the blocks can have longitudinal tracks or cut outs 9, 10 that the steel reinforcement can be laid in before the strips with joining mortar are added, this will make the use of such reinforcement easier. The most favourable cross section for such tracks/cut outs should have a dish-like or semicircular profile, as shown in fig. 4 with a width that is slightly larger than the diameter of the steel rods. The joining mortar should then easily surround the steel reinforcement.

As the thickness of the side members can be relatively thin because of the rigidity of the end walls through their bond/tie effect, the insulation unit 5 of mineral wool, can be made relatively thick so that the block has a low k-value and good resistance to heat in case of fire.

The lightweight concrete in the end walls can be of porous concrete instead of the type that has an aggregate material, such as clay clinker. The main point is that lightweight concrete combines relatively satisfactory mechanical characteristics with relatively good heat insulation properties so that the insulation blocks can be efficient bonds/ties in masonry without allowing a thermal bridge to form between the two skins/elements in the finished wall.