Foundation structure

Abstract

A building foundation structure has a supporting and heat and moisture insulating layer (17, 18, 40), preferably of foam glass. The layer rests on a flat and horizontal surface (51) of a ground layer (50). A metallic foil (111) covers the horizontal area of the foundation structure in order to prevent moisture and smell from propagating upwardly through the supporting and heat and moisture insulating layer (17, 18, 40).

Description

TECHNICAL FIELD

The present invention relates to a building foundation structure of the kind defined in the preamble of claim 1.

More particularly, the invention relates to a ground-supported foundation structure. Normally, the ground is drained and a capillarity breaking layer of material, e.g. crushed stone, is strewn over a flat and horizontal upper surface of the ground, said material having a particle size of 2-4 mm.

BACKGROUND ART

It is well known, not least from the experience gained over a long period of foundation work, that ground-supported foundations run the risk of allowing moisture to migrate through the foundation structure and into the building erected on the foundation. Smells are also liable to penetrate through the foundations. It has been found in particular that the ground's own smell “jusmine” odour, is liable to percolate through known foundation structures.

In addition to being impervious to smell/odours, it is necessary that a foundation structure can established quickly and at low cost, and that the imperviousness of the structure will satisfy the requirements of being well integrated with the foundation structure.

DISCLOSURE OF INVENTION

Accordingly, an object of the present invention is to provide a generally smell/odour impervious foundation structure that can be readily constructed in desired sizes from lightweight elements.

Foil that is impervious to jusmin odours and that retains for a very long time in the environment in which it is placed, for example a time period in the order of one hundred to several hundred years, is placed on a supporting surface, suitably a levelled layer, over the ground area. The foil is often exposed to ground moisture and moisture of condensation in an environment which will relatively often be acid or contain aggressive substances. Consequently, it is particularly suitable to choose a metallic foil material that can withstand such an environment over a long time while still retaining its imperviousness to jusmin odour.

When the metallic foil, for instance Al-foil, shall be laid essentially directly on the ground levelling layer, so that it will lie in direct contact with the granular material in said layer, the foil will preferably have a relatively large thickness, e.g. a thickness in the order of 0.1-1 mm, so as to ensure that the foil will not be penetrated when subjected, in time, to the load exerted by a building construction, via the foundation, and brought into intimate contact with the levelling layer. At such thickness, the metal foil can be obtained/delivered in roll form and unwound from the roll at the site of the foundation structure and laid over the foundation area. The foil will also have a good tear strength, therewith minimising the risk of damaging the foil as it is laid out. If, for practical reasons, the width of the foil is smaller than the width of the foundation structure, foil lengths can be lain adjacent one another with a join therebetween, e.g. an overlap join, so as to ensure the imperviousness of the foil layout to smell/odours. The overlap foil may have a width which is adapted in this respect and may include a strip or layer of glue, adhesive tape or some readily deformable foil, preferably springy foil, that has substantial width in the breadth direction of the overlap foil and therwith ensure that impermeability to smell and odours is achieved over a wide area in the air leakage direction. A single overlap joint between mutually adjacent strips of Al-foil will normally suffice, since such joints are usually pressurised along the whole of their length. The levelling surface may, of course, be covered with plastic foil prior to laying out the metallic foil, for instance in order to prevent the ingress of sand/grains into a possible overlap joint between adjacent strips of Al-foil. In one embodiment of the invention, the Al-foil may be laminated with plastic foil if so desired, for instance from handling aspect, although the relatively thick and odour proof foil, preferably aluminum foil, used in accordance with the invention is able to retain its integrity for a very long tome in its environment, which is often aggressive. The majority of plastic foils would lose their integrity in said environment over the same time of period.

In another embodiment of the invention, the odour-proof foil, e.g. Al-foil, may, of course, be placed between two layers of heat insulating material included in the foundation structure, in which case the Al-foil may be thinner, because the insulating material defines a smooth and even support surface onto which the foil can be rolled out.

The object of the invention is achieved. The invention is defined in the accompanying independent Claim while further embodiments of the invention are defined in the dependent Claims.

I the case of particularly preferred embodiment of the invention the surface of the ground is first prepared by draining the ground and then laying on the surface a layer of capillarity breaking material. For instance crushed stone, habing a particle size of 2-4 mm. anf thereafter smoothing the layer to obtain a flat and horizontal surface.

Prefabricated standard size sheets or sheets, e.g. rectangular sheets, of cellular insulating material, such as foamglas® having a thickness of 50 mm for instance are laid tightly against each other in a first layer on the crushed stone. A further layer of such sheets may optionally be lain in mutual tight abutment on the first layer, wherewith the joins between adjacent sheets of the second layer will be offset in relation to the joins in the first layer.

It is endeavoured to achieve a liquid tight joining sheets together. The cellular insulating material is preferably foamglas® or some other material that provides an absolute minimum of water adsorption or absorption and this is also highly pressure resistance and safe against vermin and that is effectively heat insulating and diffusion tight.

The insulating layers are conventionally surrounded by a frame, whose members may consist of sheet metal U-beams, wherein the concave side of respective beams faces toward the interior of the foundation element. The area within the frame is filled with pressure-strong heat insulating material, for instance two superposed layers of cellular insulation (2×100 mm foamglas). The frame of the foundation element can be stabilised, by mounting sheet-metal I-beams in said frame parallel with one of the frame U-beams. The sheet-metal beams of the foundation element are joined mechanically in a manner to stabilise the element. The foundation element may have a thickness of 200 mm for example. The use of U-beams and I-beams in respect of the foundation element means that the cellular insulating sheets can be shape-bounded to the beams by inserting those sheet portions adjacent the beams into the concave parts thereof Moreover, the upper horizontal flanges of the beams will provide anchorage points for wall construction of the building erected on the foundation structure. The building structure may be of the kind that has the form of a prefabricated box, which usually produced in a factory situated at some distance from the foundation structure. Alternatively, the foundation element may be placed separately on the foundation structure and anchored to its sheet-metal flanges.

Because we have found that even in the case of sealing foil, that has a low smell transmission capacity, the foil will allow smells and odours to wander therethrough in practice, we prefer to use a sealing layer that is comprised of a metal alloy or a metal.

So far as we are aware, aluminum foil provides desired imperviousness to odours, even at thickness as small as 0.01 mm—although thicker foils will, of course, provide greater security in this respect and will also facilitate construction of the foundation structure, since foils of the type in question can be delivered in rolls from which foil strips can be unwound and flattened and then laid on the foundation structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings, in which

FIG. 1 is a schematic vertical view of an invention foundation structure;

FIG. 2 is a schematic illustration of an overlap join between two strips of foil consisting of odour-impervious material;

FIG. 3 illustrates a variant of the subject of FIG. 1;

FIG. 4 shows another embodiment of the subject of FIG. 1;

FIG. 5,6 and 7 are respective views of frame elements in a frame construction that can be included in the foundation structure; and

FIG. 8 illustrates an embodiment of a sheet to which sealing has been pre-fitted.

MODES TO CARRYING OUT THE INVENTION

Referring to FIG. 1, it will be seen that at the site of the foundation structure there is a drained ground layer 50 which may consist of or be covered with a capillarity barrier, preferably a layer of crushed or broken stone, wherein the upper surface 51 of the barrier 50 essentially flat or horizontal.

Placed on the surface 51 is an aluminum foil or metal sheeting 111 which has preferred thickness of at least 0.1 mm, and more preferably a thickness of 0.3-0.5 mm. Established on the foil 111 is a layer of heat insulating material, preferably foamglas. Sheets of foamglas 40 are joined together and placed over the foil 111. The sheets 40 are stabilised with the aid of the frame 31 which surrounds at least the mutually joined sheets 40.

When the foil 111 is obtained in the form of strips whose width is smaller than the width of the foundation structure, the foil strips may be placed with an overlap join 112. A sealing layer, e.g. time-durable adhesive, may be applied across the width of the join to minimise the danger of smells being transmitted through the mutually joined foils 111. Alternatively, a sealed join can be established with the aid of welds, adhesive tape or there technical correspondence.

FIG. 3 illustrates an embodiment in which a layer 17 of heat insulating material, e.g. mutually joined sheets 10 of foamglas, is placed on the surface 51 of the capillarity barrier, wherewith Al-foil is placed on the layer 17, prior to placing the foundation layer, established by sheets 40 and the frame 31, on the foil 111.

FIG. 4 illustrates a variant in which a further layer 18 of sheets 10, mutually joined at their respective edges, is placed on the foil 111 before the frame with sheets 40 is placed on the layer 18.

The frame 31 surrounds the foundation layer established by the sheets 40 so as hold the foundation structure in the horizontal plane, said frame also providing anchorage points for the building to be supported by the foundation structure. According to one embodiment of the invention, the exposed parts of the edges of the sheets 40 may be recessed to receive the legs of a generally U-shaped frame member 32 (FIG. 5). In the embodiment according to FIG. 6, the frame member 32 has roughly the same height as the sheets 40 although the top and bottom surfaces of said sheets are slightly recessed to enable them to receive the legs of the frame members 32. FIG. 6 shows that I-beams 37 may be arranged in the joins between adjacent sheets 40, said sheets in the join regions recesses that receive the flanges of the I-beams can also have the same height as the sheets 40. However, it is preferred at the present distance of the frame members between said flanges corresponds to the thickness of the sheets of insulating material. The flanges on the frame members have only a small thickness e.g. thickness of 1 mm, and their position above the main surfaces of the sheets normally causes no trouble. The frame 31 normally rectangular in shape and comprises straight, U-shaped sheet metal profiles which are joined together (FIG. 7) at the corner regions of the frame by means of rivets, screw joints, glue joints or corresponding fastener means between overlapping leg portions of sheet metal profiles, which have essentially the same web measurements and a small material thickness, e.g. thickness of 1 mm.

It will be seen from FIG. 6 that rods 43 may be extended between the members of the frame 31 as to hold the frame members together in the horizontal plane.

It will be understood that the frame 31 with associated sheets 40 can form an integral part of a prefabricated box unit, so that the foundation structure and supplementing any parts of the foundation that may been earlier mounted on the site of the foundation structure, wherewith prefabricated box units may be joined together to form the body of a building on the foundation structure.

Naturally, the foundation structure can be established in the manner shown in FIGS. 1, 3 and 4, wherein the framework of a building can be erected in accordance with loose timber techniques or block techniques and anchored to the frame structure.

By way of a modification of the embodiment shown in FIGS. 3 and 4, there may be included an additional frame which grips all other heat insulating layers and possible intermediate or outwardly lying foils/metal sheets 111.

One of the heat insulating layers (17, 18) may be formed by preferably rectangular heat insulating elements 10 that are mutually joined along their edges. One main surface of respective elements 1 may be covered with a piece of metal foil 11, preferably aluminum foil. The pieces of metal foil 11 on the elements 10 can be sealingly connected with overlap joints, e.g. by overlapping strips 12 of said metal foil on the foil side of mutually adjacent elements along their respective joins. Alternatively, the foil covering on respective elements 10 may have an edge portion 12 that projects out beyond the edges of two mutually adjacent edges and overlaps the foil covering at the edges of said adjacent elements.

Both of the layers 17, 18 may be built up by joining such prefabricated sheets 10 provided with a foil covering 11. The sheets 10 of said two layers may conveniently be orientated so that their foil cladding 11 will be in mutual contact, whereby the insulating sheets 10 of the layers 17, 18 will be separated by two mutually bordering layers of foil material. The foil cladding o covering 11 on the sheets has an equivalent composition to that of the aforedescribed foil 111.

Preferably, the joins between the sheets 10 in respective layers 17, 18 will be offset in relation to one another.

Claims

1. A building foundation structure comprising a heat and moisture insulating layer encompassed by a frame that surrounds said layer resting on additional layers of heat and moisture insulating material together with a foil of metallic material parts of the frame together with parts of the heat and moisture insulating layer are integrated in respective prefabricated building box units which when placed on the underlying foundation form a building foundation structure.

2. A foundation structure according to claim 1, wherein the insulating layer consists of foam-glass.

3. A foundation structure according to claim 1 wherein the foil is located between the layer and layer.

4. A foundation structure according to claim 1 wherein the foil rests directly on said surface and the surface is comprised of a capillarity barrier layer.

5. A foundation structure according to claim 1 wherein the foil is an aluminum foil with a thickness of at least 0.1 mm.

6. A foundation structure according to claim 1, wherein the layer includes at least two courses of insulating material and the metallic foil is sandwiched between two vertically adjacent insulating courses.

7. A foundation structure according to claim 6 wherein the foil has a thickness of at least 0.01 mm.

8. A foundation structure according to claim 6, wherein in cach the layers is formed by mutually joined sheets of insulating material, one main surface of each sheet is covered with a piece of foil, the layers carry said foil pieces on their mutually facing sides, a strip of said foil material, sealingly joins together the foil coverings or cladding on adjacent sheets in at least one of the layers, and so that the joints between the sheets in respective layers are offset relative to each other.

9. A foundation structure according to claim 1, wherein the strips are formed by edge portions of the sheet-covering foil that protrude beyond the edge portions of respective sheets along two adjacent edges thereof, wherewith the outwardly projecting edge portions of said foil coverings are caused to overlap an adjacent edge portion of the foil coverings of adjacent sheets.