The method of the construction of passive foundation and, in particular, of connecting them with walls is characterised in that in order to improve the thermal insulation so as to limit the heat losses for a building or to simplify the structure or to reduce the building costs, the surface of the foundations or the contact surface of building materials/structural foundations (2) and building materials/structural walls (3) is purposefully reduced i.e. by being partly replaced with a column structure (made i.e. of reinforced concrete) (6) and partly with horizontal thermal insulation (7), whereas thermal insulation, which is an important objective of this operation, is placed under the walls of the building or between the foundation and the walls in places where the continuity of the foundations (walls) is limited/interrupted (between the columns). Horizontal insulation is therefore located under a considerable part of the walls, except for the surface of the poles.

Methods of vertical insulation of foundations (including walls) - on the side of the foundation are known and widely used in the construction industry. This does not, however, insulate the entire surface of the foundations that are in contact with the ground, but only their sides.

A key issue, in particular in low-energy and passive construction industry, is the lack of horizontal thermal insulation of bottom parts of walls or foundations, since these constitute virtually one continuous plane of the flow of heat from the building to the ground. This is due to the fact that the foundations carry the load of the entire building, whereas insulation materials (XPS, Styrodur, etc.) are not strong enough to transfer this load (and thus cannot function as horizontal insulation under the entire structure of the building).

It should be noted, however, that the transfer of heat between the building materials (e.g. brick, concrete, foundation blocks, etc.) of the foundations and walls (of the building) largely depends on the surface area through which heat can flow to the ground. The contact surface of the foundations and walls is generally approx. 20-50 cm wide; this relates only to the contact surface of building materials i.e. concrete or bricks, not the entire wall with the insulation).

The present solution is to reduce the area of the contact surface and replace it partly with horizontal insulation and partly with load-bearing column structure i.e. continuous footing, or possibly with a different type of structure that would reduce the area of the cross-sections of the foundations or the walls to reduce heat transfer.

A method of insulating foundations from the bottom is also known - application No. 390772 to the Patent Office of the Republic of Poland "Stay-in-place formwork, especially for foundation footings and walls, which simultaneously acts as thermal and damp-proof insulation that insulates the foundation particularly from the bottom, made of extruded polystyrene (XPS)". This solution, however, does not provide adequate strength and cannot be used with majority of buildings. Moreover, apart from the bottom insulation of the foundation, it is also possible to reduce, as proposed in this application, the contact surface of the foundations and walls and thus reduce the heat transfer between the foundations and walls. The proposed solution is also much cheaper and easier to implement.

A column structure is also known, although walls, including foundation walls, are usually made of concrete, bricks, blocks or other building materials with weak insulation parameters that enable the continuity of heat conduction from the building through the foundations of the ground, and therefore there is no critical horizontal thermal insulation between the foundations and walls. Additionally, these structures are designed for simplicity, not to reduce heat transfer.

The technique of micropiling also does not interrupt the continuity. In this technique, in contrast to traditional foundations, the differences involve the part of the foundation which is buried in the ground - not the plinth nor the method of insulation of the walls or foundations.

The technique of implementing horizontal damp-proof insulation between the foundations and walls is also known and widely used. This insulation, however, does not meet the requirements of thermal insulation. In the present solution, horizontal thermal insulation plays an important role. It can also function as a water and damp-proof (polystyrene, aquastyr, XPS) insulation, as well as the discontinuity of materials that draw water. Regardless of the present proposal for thermal insulation, it may also be used as water and damp-proof insulation.

Advantages

In general, the advantages can be divided into those resulting from the reduction of heat transferred through the walls and foundations to the ground, and the technical and economic advantages due to the simplification of the house-building process.

The advantages related to the reduced heat transfer through the wall and the foundations to the ground are due to the large reduction of the area of the contact surface (continuity) of the structural elements of the walls and the structural elements of the foundations.

In traditional construction industry, the structure of a building is characterised by the continuity of its structural elements (especially foundations and walls of the building), since these structural elements (bricks, blocks, concrete) are very inefficient as thermal insulators. Walls are laid directly on the foundation (setting aside the issue of damp-proof insulation), which results in a large area of heat transfer between the walls and foundations, and in turn with the ground. In the present solution, this surface is very significantly reduced, as typical foundations traditionally extending along the entire circumference of the house and under other structural walls have been replaced with reinforced-concrete column structure (or walls with smaller sections or walls not extending along the entire length of the foundations but only as spots/sections). This structure has a much smaller surface area through which heat transfer occurs, however, due to the excellent strength of concrete, it is sufficient to transfer the entire load of the building to the continuous footing or a foundation of different type. The columns may be of any shape, including oblong or turning shapes (at corners), depending on the shape/course of the foundations (it can include foundation walls with reduced surface/cross-section areas). The reduction of the surface area of the foundations (replacing walls with columns) is a very significant advantage, since the heat loss through the foundations is reduced by a factor of a few, a dozen or several dozens. Assuming concrete strength of 15 MPa (or 150 kg/cm ² ), a weigh of an example house of 150 tons can be transferred by columns with an area of 0.1 m ² , i.e. by 4 columns with dimensions of 10/25 cm. By default, the contact area of the foundations and the walls depends on the length of the foundations, which often exceeds 50 m (single-family detached house) and the width along which the walls are based on the foundations - i.e. 25 cm - which gives an area of 12.5 m ² . This value is more than a hundred times greater than that obtained from the calculations for the columns and heat transfer is generally proportional to that surface. Due to structural reasons, for most buildings it is necessary/reasonable to place more columns/supports than the said 4, however the heat loss reduction factor can still be in the range of several dozen.

The simplified construction of the foundations, in particular the reduction of the costs and shortening the time constructing and insulating foundation walls is an additional advantage. Typically, the entire foundation wall should be made of solid materials (blocks or concrete) and should be thermally insulated (polystyrene, aquastyr, XPS), and, in the case of low-energy and passive houses, this insulation should be located on both sides of the foundation, and damp-proof insulation or other items such as dimplet membrane should be additionally taken into account. The need to use all these items can be eliminated or greatly reduced - to as little as is needed for the surface of the poles, with an area several dozen times lower. The economic, technical, organisational and time-related benefits are substantial.

Application

The proposed solution is primarily used in the construction of low-energy and passive single- family detached houses, as well as in the construction of other forms of single-family houses, and in traditional, multi-family, industrial, warehouse, residential, office, resort, skeleton construction and other sectors of the construction industry.

The present solution can be applied in different variants. Basically, the method of the construction of passive foundation or of connecting them with walls is characterised in that in order in order to improve the thermal insulation so as to limit the heat losses for a building or to simplify the structure or to reduce the building costs, the surface of the foundations or the contact surface of building materials/structural foundations (2) and building materials/structural walls (3) is purposefully reduced i.e. by being partly replaced with a column structure (made i.e. of reinforced concrete) (6) and partly with horizontal thermal insulation (7), whereas thermal insulation, which is an important objective of this operation, is placed under the walls of the building or between the foundation and the walls in places where the continuity of the foundations (walls) is limited/interrupted (between the columns). Horizontal insulation is therefore located under a considerable part of the walls, except for the surface of the poles.

It is preferable for the method in variant 1 that the horizontal insulation or the reduction of the surface area of the walls may be made at different heights, in particular under the building wall, but also between the continuous footing and the foundation wall, at the height of the foundation wall or the height of the building wall.

It is preferable for the method in variant 1 that it is possible to completely eliminate the foundation walls and consequently their insulation and cover, and to replace the walls with a column/skeleton structure laid i.e. on continuous footing, or to reduce the amount of foundation walls, i.e. by lowering their height.

It is preferable for the method in variant 1 that foundation walls are replaced with only thermal insulation or other type of partition (metal sheet or mesh, precast elements) in order to reduce the transfer of heat or the amount of rodents penetrating into the area under the floor. It is preferable for the method in variant 1 that the skeletal structure can be replaced with walls whose cross-sections are smaller, or with walls not extending along the entire length foundation but placed only as spots/sections. It is a matter of nomenclature whether these structures are defined as columns or walls.

It is preferable for the method in variant 1 that it can include additional reinforcements, in particular to improve the resistance to bending of the column structure.

It is preferable for the method in variant 1 that it can be used in connection with buildings and foundations of any shape.

It is preferable for the method in variant 1 that the foundation can be of any kind i.e. as spots under the columns, without having to lay continuous footing.

It is preferable for the method in variant 1 that the solution can be used for a variety of structures in the construction industry, i.e. in skeletal, metal, wood structures, or other light structures, or in industrial construction.

It is preferable for the method in variant 1 that the structure of the foundations can be made of all sorts of materials including i.e. steel.

It is preferable for the method in variant 1 that the cross-sections of columns or foundation walls can be of various shapes at different heights (e.g., can be conical or stepped), for example with a larger cross-section at the bottom of the column (area of contact with the footing) to provide better stability, and with a smaller cross-section at the top to transfer less heat or lower the costs of manufacturing.

Description of the figures

Fig. 1 shows examples of the solutions used so far, where the wall of a building (3) is placed on a foundation (2), which is placed on a foundation footing (1). There may also be a thin layer of damp-proof insulation between these elements, but it was not added to the figure as it is irrelevant in this case. On the outside of the building there is thermal insulation of the walls (5), in some cases also thermal insulation of the foundations (4), whereas sometimes thermal insulation of the foundations is added on the inside of the building to provide additional insulation. The continuity of the wall (3), foundation (2) and foundation footing (1), which is in contact with the ground (this is also often the case for the foundation wall) causes the loss of large amounts of heat, which is transferred to the ground.

An example of the implementation of the foundations as presented in this application is shown in Fig. 2, which includes foundation footing (1), but above it there is a pillar structure (6), which transfers onto the foundation the load of the entire building, including the walls (3), which include horizontal insulation to prevent the heat from flowing into the ground. The heat is transferred through the column (6) out of the building and in the direction of the foundations and the ground. This surface, however, is many times less than the heat transfer surface of a typical foundation. The horizontal insulation (7) between the wall and the foundation (especially directly against the wall) is of key importance, whereas in the case of the column structure the existing foundation wall can be replaced with any filling (8) i.e. condensed dirt (ground), thermal insulation (without load-bearing structure), or with metal sheet or mesh (protection against intrusion of rodents into the house), precast elements or other components. For the reasons of strength, it is recommended to add a strong structural beam in the lower part of the building wall (3), which will be attached to the pillar (6). The side insulation of foundation walls is limited in this case only to the surface of the column. Foundation walls with cross-sections smaller than the existing ones, or walls that do not extend along the entire length of the foundations only as spots/sections can be used instead of columns. It is a matter of nomenclature whether these are defined as columns or skeletal structures or as walls with smaller cross-sections.