EP0184793B1 - Device for keeping the ventilation section of a two-akin roof free, method for restoring a two-akin roof and guiding dowel for carrying out the method - Google Patents

Abstract

1. A device for maintaining the ventilation air gap between the upper side of a thermal insulation (8) disposed between the rafters (9) of a finished two-skin roof and the underside of the outer roof skin (1), consisting of elements (13a) laid side by side in the squares in the direction of the slope of the roof, said elements being open at both ends and provided with large openings (16) and snugly filling in the ventilation air gap, characterized in that the elements (13a) consist of substantially rigid, right parallelepiped hollow boxes (13) and the openings (16) are provided in both covering surfaces of the elements (13a).

Description

The invention relates to a device for keeping the ventilation cross section of a double-skin roof free, a method for renovating a double-skin roof and a guide wedge for carrying out the method according to the preamble of claims 1, 15 and 19.

A sloping roof generally has a double-shell structure in the area of a converted attic. The outer shell usually consists of the roof covering and a formwork arranged underneath with a covering made of cardboard, while the inner shell has a thermal insulation layer with an internal vapor barrier and a plasterboard shell on the room side. For the purpose of adequate top ventilation of the thermal insulation layer, which generally consists of mineral wool insulation sheets, a free ventilation cross-section must be formed between the two roof shells, the height of which depends on the roof pitch, but should not be less than a minimum height of 5 cm.

To maintain dry and therefore functional thermal insulation, it is important that the air flow in this space between the two roof shells is not adversely affected by any obstacles. It is necessary that a flow cross section that is as constant as possible is maintained.

In practice, however, it often happens that there is insufficient ventilation on the upper side of the thermal insulation. For example, there are technical reasons for this if the insulation sheet to be installed is selected a few centimeters wider than the rafter spacing in order to avoid thermal bridges with certainty. The consequence of this is that the excess width towards the ventilation cross section is shown as a bulge, so that the free ventilation cross section is reduced inadmissibly. In addition, material problems can be the reason for inadequate ventilation, since a deviation from the specified nominal thickness of 30% is expressly permitted for mineral wool insulation sheets.

An insufficiently dimensioned free ventilation cross-section results in more or less strong condensation in the insulation material. This is compounded by the fact that mineral fiber insulation sheets have a significant suction capacity. Beginning moisture penetration of the insulation material results in a considerable reduction in the thermal resistance of the insulation layer, which further promotes the continuation of this unfavorable development. This development can lead to the insulation layer being so enriched with moisture that an adequate thermal insulation effect can no longer be assumed. In such a case, the inner shell of the roof structure and the load-bearing parts of the roof are also affected.

So far it has been necessary in such a case of damage to remove the existing roof covering, the entire battens and counter battens as well as the covering and roof formwork and to insert a new thermal insulation layer, whereupon the outer roof shell has to be reattached. These remedial measures are associated with a considerable amount of work and considerable costs.

From GB-A-2 075 565 a device for keeping the ventilation cross section free is already known between the top of a thermal insulation arranged between the rafters of a removed double-skin roof and the underside of the outer roof shell in the form of flat components which are attached to the two lateral edge sections L are angled in a shape. With these angled edge sections, the known components rest on two adjacent rafters, whereby. they are attached to them, while their flat main section connects the rafters to each other at about half their height, so that the upper area between the rafters is kept free as a ventilation cross section. These essentially flat components can consist, for example, of plastic or a wire mesh. A disadvantage of the known device is that the components which keep the ventilation cross-section free are to be installed when the roof is being built, whereas they cannot be retrofitted for roof renovation without removing the upper roof shell.

The invention has for its object to continue to develop a device according to the preamble of claim 1 in such a way that its individual elements can be installed both in the manufacture of a double-skin roof and subsequently for its renovation. In addition, a method for the renovation of a removed double-skin roof and a guide wedge for carrying out the method are to be specified.

This object is achieved by the features specified in the characterizing part of claims 1, 15 and 19. Advantageous developments of the invention are characterized in the subclaims.

The device according to the invention has elements made of essentially rigid, rectangular hollow boxes, these elements being provided with openings in both top surfaces. With the help of these elements, a supply and exhaust air cross section of a certain size is determined, the required free ventilation cross section being able to be subsequently produced by arranging such elements between the two shells of a two-shell roof construction. To insert such an element between the roof shells, no preparatory measures are necessary on the roof structure, in particular it is not external roof covering for this purpose, but the element can be easily inserted into the space between the shells from the pointed floor above the roof's extended attic. Such a remedial measure leads to considerable cost savings compared to the previously customary measures.

The side surfaces of the elements facing the rafters advantageously have further openings. This also allows any lateral areas adjoining the element to be ventilated.

It also proves to be advantageous that the openings in the lower surface of the elements are closed with a smooth, vapor-permeable cover. This design reliably prevents the thermal insulation material from entering the element through the opening in its underside. Even if the thermal insulation layer, as a result of a leak in the roof covering, would endeavor to swell due to the ingress of moisture, this would be prevented by the covered underside of the element, while at the same time ensuring the required passage of air through the lower cover.

The interior of the elements is advantageously divided into individual chambers by longitudinal webs running perpendicular to the cover surfaces and parallel to the rafters. This configuration on the one hand increases the stability of the element, while also reducing the formation of eddies in the element by the flowing air flow and promoting the formation of a purely laminar air flow. The chambers advantageously have essentially the same cross sections. Two longitudinal webs can be arranged in each element.

It is also advantageously provided that complementary parts of a snap lock are arranged on both sides of the elements in such a way that with the aid of these parts adjacent elements with abutting end faces can be connected to one another in a force-locking manner. Since a continuous free ventilation cross section extending from the eaves to the pointed floor must be formed with the aid of several elements for adequate ventilation of the thermal insulation layer, the elements can be reliably aligned with one another by this measure. The parts of the snap lock are expediently arranged on at least one of the central longitudinal webs, as a result of which the risk of an element being jammed when being fed into the space between the two roof shells is reduced.

The parts of the snap lock expediently consist of a pivotable angle piece and a flat web which is engaged by this. This makes the connection quick and easy.

The elements of the device according to the invention expediently consist of plastic. The material is chosen so that the elements have the required rigidity. The cover for the openings in the lower cover surface of the elements expediently consists of a glass fleece or a polyester fleece.

The height of the element according to the invention is expediently 50 mm, which ensures a sufficient ventilation cross section for all roof inclinations. The width and the length of the element are expediently 550 mm and 400 mm. These dimensions are matched to the rafter distances that are usually encountered and to the transport problems of the elements, but other dimensions with regard to length and width are also possible.

In order to facilitate the transport of the elements, it is furthermore advantageously provided that articulated straps are arranged at the ends of the elements and connect articulated elements to one another. This enables the elements to be transported to the place of use as a collapsible package.

The method according to the invention for the renovation of a double-skin roof that has been removed provides that several elements are inserted one after the other with the end faces lying against one another into the space between the top of the thermal insulation and the underside of the outer roof shell until one in each rafter field of the roof from the eaves to the pointed floor continuous free ventilation cross-section is made. As already mentioned above, this method can be carried out without dismantling the outer roof shell, which makes it simple and cost-effective to carry out. The elements are expediently pushed into the intermediate space from the pointed floor of the roof.

It is advantageously provided that an insertion-facilitating guide wedge is fastened in the front end of the first element in each rafter field, which is folded after the insertion of all elements into the relevant rafter field and is pulled out to the rear. The first element in each rafters field is expediently advanced by means of a collapsible guide rod, which has at its front end a cross member which is supported on the guide wedge. The guide rod must therefore be designed to be collapsible because there is generally not much space available in the area of the attic above the converted attic. The guide rod is designed in the opened state so that it can support the installation process effectively mechanically.

According to the invention, a guide wedge is also provided for carrying out the method, which has two expanding jaws which are connected to one another via a centrally arranged joint and, in the installed state, protrude from the front end of the first element and form a wedge has, the free ends of which are articulated at the free ends of an articulated support formed from two articulated parts in such a way that they are pressed against the inside of the front end of the element in the extended position of the articulated support, while in their articulated position caused by a cord pull attached to it and guided to the rear end of the element can be brought about, are pivoted against each other, whereby their guide wedge can be released and pulled out of the element. This guide wedge facilitates the insertion of the elements by pushing down the excessive thermal insulation material during the feed. Only the first element of a row of elements leading from the pointed floor to the eaves is provided with the guide wedge, since the subsequent elements can easily be inserted into the already widened intermediate space. When the element provided with the guide wedge reaches an advanced position, the guide wedge is folded together by means of the cord and pulled out of the elements so that it does not obstruct the air flow.

With the aid of the device according to the invention, however, not only the free ventilation cross section which has been lost or which has already been insufficiently dimensioned from the start can be obtained by subsequently introducing an arrangement of elements extending from the eaves to the ridge. Of course, there is also the possibility of installing the elements from the start in the space between the two shells of a double-skin roof to ensure that the ventilation cross section provided remains unchanged.

Since the elements are expediently inserted from the pointed floor of a roof, in which only a limited space is available, into the space between the two shells, they expediently have a relatively short length. This has an additional advantage that the individual elements are easy to transport.

The length of the respective arrangement of ventilation elements extending from the eaves to the pointed floor can be changed as desired simply via the number of individual elements joined together. A change in the element width can only be necessary if the dimension specified in this regard must be considered too large due to the local conditions. In such a case, it is possible at any time to split the existing box profile of the elements on the left or right or on both sides and to push the outer section into the existing construction to the desired overall width. This process is facilitated in that the elements consist of a plastic. A suitable mechanical connection in the area of the overlapping profile sections can then be used to easily produce an entire individual element again. In this way, the element width can be reduced to the desired level without any special effort.

The arrangement of the glass or polyester fleece on the underside of the element ensures that, in addition to the purely mechanical requirement, the diffusion-equivalent air layer thickness of the thermal insulation in the interface with the free ventilation cross section is not increased or is not significantly increased. This is of crucial importance for the desired renovation success.

• Fig. 1 ein erfindungsgemäßes Element in einer perspektivischen Ansicht;
• Fig. 2 einen Querschnitt durch eine zweischalige Dachkonstruktion mit eingeführten Elementen;
• Fig. 3 einen Längsschnitt durch die Dachkonstruktion gemäß Fig. 2;
• Fig. 4 einen Querschnitt durch den Schnappverschluß;
• Fig. 5 eine Schnittansicht entlang der Linie A-A in Fig. 4;
• Fig. 6 eine Seitenansicht eines demontierbaren Führungskeils;
• Fig. 7 einen zusammenfaltbaren Führungsstab und
• Fig. 8 eine Transportanordnung der Elemente.

The invention is explained below using an exemplary embodiment with reference to the drawing. Show:

• 1 shows an element according to the invention in a perspective view;
• 2 shows a cross section through a double-shell roof structure with inserted elements;
• 3 shows a longitudinal section through the roof structure according to FIG. 2;
• 4 shows a cross section through the snap lock.
• Fig. 5 is a sectional view taken along the line AA in Fig. 4;
• 6 shows a side view of a removable guide wedge;
• Fig. 7 is a collapsible guide rod and
• Fig. 8 shows a transport arrangement of the elements.

The roof structure shown in Fig. 2 consists of an outer shell 1 and an inner shell 2, between which an air space 3 is formed. The outer shell 1 comprises a roof covering 4 with an underlying battens 5, a counter battens 6 and a formwork 7 with a cardboard covering. The inner shell 2 consists of the thermal insulation layer 8, which is arranged between the rafters 9, a vapor barrier 10 arranged underneath, and a further battens 11, to which a plasterboard shell 12 is attached.

The element 13a shown in FIG. 1 consists of an essentially rigid, cuboid hollow box 13, the two opposite end faces 14 and 15 of which, like the two cover surfaces, have large openings 16. The side surfaces 17 of the hollow box 13 facing the rafters 9 have further openings 18.

The hollow box 13 is divided into two chambers 20, which are of the same size, by two vertical, I-shaped longitudinal webs 19. The bottom opening of the element 13a is closed by a smooth, vapor-permeable cover.

FIGS. 2 and 3 show the state in which the roof shown is provided for its renovation with elements 13a which are inserted between the formwork 7 provided with the covering and the thermal insulation layer 8 in order to form a sufficient ventilation cross section.

The snap lock 21 shown in Figures 4 and 5 consists of a ver pivotable on the front end portion of the one element 13a angled piece 22 and a flat web 23 which is arranged on the rear end section of another element 13a and is engaged by the angled piece 22. The two parts 22 and 23 of the snap lock are attached to aligned 1-shaped longitudinal webs 19.

The demountable guide wedge 24 shown in FIG. 6 contains two spreading jaws 26 which are connected to one another via a centrally arranged joint 25 and which can be stiffened by two articulated parts 27 which are also connected to one another at 28 so that the spreading jaws against the upper and the lower edge portion of the element 13a are pressed. The element 13a provided with the guide wedge can easily be inserted between the two shells 1 and 2 of a two-shell roof construction. When the element 13a provided with the guide wedge 24 has reached the desired position, the parts 27 are bent backwards by means of a cord 29, as a result of which the expanding jaws 26 are pivoted towards one another so that the guide wedge 24 can be pulled out of the element.

The guide rod 30 shown in Fig. 7 can be used to push the elements 13a forward in the space between the shells 1 and 2. For this purpose, the guide rod is provided with a front cross member 31. Since there is usually only a limited space available for handling the guide rod on the pointed base from which the elements are introduced, it can be folded up at joints 32, it being provided with suitable means, not shown, for stiffening it in the stretched state.

FIG. 8 shows a transport arrangement made up of a number of elements 13a which are connected at the end faces by means of articulated straps 33 made of plastic. The elements 13a can thus be transported to the place of use as a collapsible package, which further simplifies roof renovation.

Claims (19)

1. A device for maintaining the ventilation air gap between the upper side of a thermal insulation (8) disposed between the rafters (9) of a finished two-skin roof and the underside of the outer roof skin (1), consisting of elements (13a) laid side by side in the squares in the direction of the slope of the roof, said elements being open at both ends and provided with large openings (16) and snugly filling in the ventilation air gap, characterized in that the elements (13a) consist of substantially rigid, right parallelepiped hollow boxes (13) and the openings (16) are provided in both covering surfaces of the elements (13a).

2. The device of claim 1, characterized in that the side surfaces (17) of the elements (13a) facing the rafters (9) have further openings (18).

3. The device of claim 1 or 2, characterized in that the openings (16) in the lower covering surface of the elements (13a) are sealed by a smooth vapor-permeable cover.

4. The device of any of claims of 1 to 3, characterized in that the interior of the elements (13a) is divided into individual chambers (20) by longitudinal bars (19) extending at right angles to the covering surfaces and parallel to the rafters (9).

5. The device of claim 4, characterized in that the chambers (20) have substantially the same cross sections.

6. The device of claim 4 or 5, characterized in that two longitudinal bars (19) are disposed in each element (13a).

7. The device of any of claims 1 to 6, characterized in that complementary parts of a snap (21) are disposed at each end of the elements (13a) in such a way that these parts allow adjacent elements (13a) to be frictionally interconnected with adjacent faces (14. 15).

8. The device of claim 7, characterized in that the parts of the snap (21) are disposed on at least one of the middle longitudinal bars (19).

9. The device of claim 7 or 8, characterized in that the parts of the snap (21) consists of a pivotable elbow (22) and a flat bar (23) engaged behind by said elbow.

10. The device of any of claims 1 to 9, characterized in that the elements (13a) are made of plastics material.

11. The device of any of claims 3 to 10. characterized in that the cover for the openings (16) in the lower covering surface of the elements (13a) is made of a nonwoven fabric of glass or polyester.

12. The device of any of claims 1 to 11, characterized in that the height of the elements (13a) is 50 mm.

13. The device of any of claims 1 to 12, characterized in that the width of the elements (13a) is 550 mm and the length 400 mm.

14. The device of any of claims 1 to 13, characterized in that hinge strips (33) made of plastics material are disposed at the ends of the elements (13a) for hinging together adjacent elements (13a).

15. A method for renovating a finished two-skin roof having thermal insulation disposed between the rafters and a ridge floor located above the habitable attic, characterized in that a plurality of elements (13a) as in any of claims 1 to 14 are successively inserted with adjacent faces (14, 15) into the space between the upper side of the thermal insulation (8) and the underside of the outer roof skin (7) until a free ventilation air gap extending continuously from the eaves to the ridge floor is produced in each square of the roof.

16. The method of claim 15, characterized in that the elements (13a) are inserted into the space from the ridge floor of the roof.

17. The method of claim 15 or 16, characterized in that a guide piece (24) for facilitating insertion is attached in the leading end of the first element (13a) in each square, said guide piece being collapsed and pulled out backwards after all elements (13a) have been inserted into the square in question.

18. The method of claim 17, characterized in that the first element (13a) is pushed forward in each square by means of a collapsible guide rod (30) having at its front end a transverse bar (31) to be supported on the guide piece (24).

19. A guide piece for carrying out the method of ciaim 17 or 18, characterized in that it has a pair of spreader jaws (26) hinged together in the middle (25) and protruding out of the leading end of the first element (13a) in the installed state and forming a wedge, their free ends being hinged to the free ends of an articulated support formed by a pair of hinged together parts (27) in such a way that they are pressed in the stretched position against the inside of the leading end of the element (13a), while in their bent position, to be brought about by cords (29) attached thereto and directed to the trailing end of the element (13a), they are swiveled together so that the guide piece (24) can be detached and pulled out of the element (13a).

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