The invention relates to a load distributing base element fixing the fittings of composite flat roofs.

Presently several different structures are known for fixing superstructures on flat roofs. One of these is a structure system built on a reinforced concrete or steel frame base. Such superstructures can be positioned relatively freely, they can take into consideration the position of other superstructures on the roof, due to its elevated structure it does not burden the roof and does not prevent self- cleaning, and later renovation of the roof can also be solved. However, a disadvantage of this system is that because of the significant span (5 - 8 m) the steel girders connecting the column footings have a large wall thickness and a significant cross-section, so they are very heavy. Another disadvantage is that the entire roof layer system needs to be dismantled, and there is a risk of leaking until final fitting.

Another known structure involves fittings mounted on the roof insulation, on PVC-based rails. Although it is quick to install, and the fittings can be easily fixed to the aluminium core, it has numerous disadvantages. On the one part it cannot be used freely, it can only be built on a mechanical fixing strip. In the lack of this a separate fixing strip needs to be installed, by changing the strips. A further disadvantage of it is that due to its small size it is very sensitive to the compressive strength

characteristics of the heat insulation, it has a small load transfer surface. Another disadvantage is that full compatibility is restricted to one single type of water insulating material, it needs to be installed densely spaced (80-90 cm) , later renovation of the roof insulation is difficult to realise, and its installation requires special equipment.

The base element according to the attached figure is the intermediate structural member for the fixing and

connection of superstructures (solar panels, solar

collectors, etc.) installed on composite flat roofs.

The geometrical dimensions of the base element, with special respect to the thickness of the material and the resting surface, as a load distribution surface, can be freely changed according to the technical circumstances and the loading of the roof and the superstructure, on the basis of static dimensioning.

The material of the base element can also be selected on the basis of static dimensioning, knowing the loads and uses occurring, so the load bearing material can be

plastic, alloyed aluminium or corrosion-proof steel.

Structural connection to the flat roof is ensured by system-compatible self-tapping roof bolts fitted into the countersinks on the horizontal plate shanks of the base plate, which roof bolts, in the case of a light-structure roof, are typically spaced at a distance of 280 mm from each other, ensuring by this the possibility of fixing the roof structure load bearing trapezoid sheeting per rib. In the case of heat insulation of a lower compressive strength an important requirement with respect to fixing bolts is that the neck part should have a so-called supporting threaded construction, as this threaded neck bears the small compression differences deriving from the compressive strength and physical unevenness of the heat insulation .

Double-sided self-adhesive tape of the necessary width and thickness fitted to the bottom of the base plate partly fixes the profile and minimises the possibility of leaking while work is performed. The thickness of this tape can vary depending on the quality and compressive strength value of the existing heat insulation, stabilising and counterbalancing by this load transfer and indentation problems .

The base element is fitted under factory circumstances with water insulation identical to or completely compatible with that of the water insulation system of the roof to be built, in such a way that on the two longitudinal sides the water insulation overhangs. This overhanging water

insulation part is constructed with an impermeable

connection suiting the given technological necessity (with flame, hot air, cold adhesive) , according to the technical prescriptions relating to the use of the existing roof insulation .

Dimensioned, metric-threaded, hexagon-head stud bolts are fitted to the profile for accommodating and fixing the superstructures and fittings, depending on the material of the profile, with impermeable welding or polymer resin adhesive. The stud bolt is the upper fixing point (locking clamp) created on the base element according to the present invention, which has a receiving joint element for fixing the flat roof fitting. The stud bolt creates an impermeable tight connection with the insulating layer. The fittings are fixed to the stud bolt with a nut

connection. The movements and vibrations of the fittings caused by thermal and wind-load are assumed by a so-called locking clamp, as a friction surface, ensuring load and stress relief of the water insulation in this way. At the same time this profile also ensures the tight impermeable sealing of the breakthrough points on the side of the water insulation .

The trapezoidal shaping of the base element can be filled with a heat-insulating core of the necessary material and quality. It prevents condensation by contact of the vapour possibly diffusing inside the profile, and continues to increase the resting and load distribution surface of the base element.

In the present specification the term flat floor fittings is used to refer to fittings and equipment installed on flat roofs, such as solar pa: els, solar collectors.

In figure 1 the schematic cross-sectional view of the base element according to the invention can be seen. The base element has a load distributing element 1 with a profile ensuring protrusion. Protrusion is needed to ensure that the locking clamp protrudes from the roof plane. Preferably the load distributing element 1 has an omega profile (as shown in the figure) , as this profile has proved to have appropriate load bearing characteristics. The profile of the load distributing element 1 is a geometrical shape optimised from the aspect of loading. The material of the load distributing element 1 can be, for example, steel, aluminium or suitable plastic, e.g. polyethylene-based plastic .

On the load distributing element 1 there is a mounted insulating layer 2. The insulating layer 2 overhangs the edge of the load distributing element 1 so that the

insulating layer 2 can made impermeably continuous with the roof insulation (not shown here) . Consequently the material of the insulating layer 2 is the same as the material of the roof insulation.

Furthermore, the base element has one or more stud bolts 3 penetrating the surface of the load distributing element 1 and, at the same place, the surface of the insulating layer 2. The stud bolt is used for fixing and receiving the superstructures (not shown here) installed on flat roofs. The stud bolt 3 is fixed to the load distributing element 1 in an impermeable way. Impermeable fixing can be ensured, for example, by welding or using resin. Furthermore, the stud bolt 3 also penetrates the insulation material 2 in an impermeable way.

According to a preferred embodiment of the base element according to the invention, around the stud bolt 3 there is a washer 4 resting on the insulating layer 2. The washer 4 ensures the protection of the insulating layer 2, as the superstructure rests on the stud bolt or on the surface around the stud bolt. In the lack of a washer the

superstructure would rest on the insulating layer 2, which would result in the early deterioration of the insulation (wear-and-tear, etc.). The base element according to the invention can be fixed through the feet 5 of the base element resting on the roof insulation, for example, with roof bolts 6. Within this fixing strip the position of the joint elements is created suiting the type of the joint elements. Preferably the feet 5 contain a countersink 7 at the fixing points. The aim of the countersink 7 is to keep the head of the roof bolts at a level where the insulating material layer 2 cannot bulge when resting on this area, but the surface of the

insulating layer 2 remains even on the feet 5.

Preferably, the base element according to the invention is fitted as described below. Preferably, the insulating layer 2 is fixed to the load distributing element 1 only around the stud bolt 3, so the insulating layer 2 can be folded up from the feet 5. The feet 5 function as a fixing strip. When the insulating layer 2 is folded up from the feet 5 (that is from the fixing strip) , the fixing points on the feet 5 become accessible, where the roof bolts can be screwed in. According to the preliminary dimensioning of the tensile, shearing and compressive stress, the feet 5 (the fixing strip) can be connected to the load-bearing structure of the roof leaving alone the roof layer system, without opening it up. As mentioned above, practically the fixing points are created as countersinks. After completing the fixing, the insulating layer 2 can be folded back onto the feet 5. As the insulating layer 2 overhangs the edge of the load distributing element 1 (that is the edge of the feet 5), the edge of the insulating layer 2 is in contact with the original roof insulation. The overhanging part of the insulating layer 2 functions as an overlap, so it covers the existing roof insulation there. The two

insulating materials, preferably made of the same material, in contact with each other in this way can be fixed to each other impermeably using a thermal or chemical method (e.g. using tetrahydrofuran) . In this way, in the insulation plane on the roof an overlap of the same technical

application value can be created by creating an impermeable water insulation connection (attachment) . The feet 5 are fixed with the roof bolts 6 in the direction of the already existing insulation, through the impermeable working strip created depending on the condition of the roof.

The base element according to the invention makes it possible to create impermeable load-bearing structures on flat roofs, especially on insulated flat roofs. If during the fitting of the base element it rains or there is any other precipitation, there is no risk of leaking, as the roof structure is not opened at all during fitting which would allow leaking.

The base element according to the invention has the

following advantages:

- the material thickness of the profile, its material characteristics and size can be changed to suit static demands ;

- due to its mechanical fixing it can be easily dimensioned for loads affecting the roof;

- it stabilises the existing roof, it increases resistance to wind suction, which increase can be expressed in

numbers ;

- it tolerates the quality differences of thermal

insulation within a wide range;

- it can be spaced to suit the demands of the fitting, so the already existing other breakthrough points on the roof can be taken into consideration completely; - it can be previously manufactured with any type of roof insulation material under factory circumstances (bituminous plate, EPDM, PVC, TPO, etc.), compatible with the roof insulation system already existing at the construction site, which has an outstanding significance from the aspect of guarantee;

- the base element arrives at the construction site as a prefabricated finished product;

- it is easy to install, it can be installed by persons having average roof insulation skills and equipment;

- the stud bolt fixing of the superstructure part is suitable for bearing large loads, and it also makes the system element easy and simple to dimension, the bolt joint is created in a qualifiedly impermeable way;

- it is suitable for taking over or for the stable fixing of a walkway, cable tray, inverter carrier, etc., so the use of the already existing roof insulation can be

significantly reduced, and the so-called self-cleaning of the roof does not deteriorate;

- in the case that the roof insulation is repaired or renovated at a later point, the base elements do not prevent such work, the base elements can be spaced to suit the typical roll width of the given water insulation material, and so in the case of renovation realised at a later point the new insulation can be installed simply, without waste;

- the materials and production technologies of the base element can be easily obtained or produced, so according to market demands the production capacity can be extended quickly, to suit demands;

- if necessary, it can constructed with heat insulation too .