Roofing and roofing units for use therein

Abstract: Roofing of the type comprising a number of adjoining roofing units (1) and joining means (7) for joining the roofing units. Each roofing unit (1) comprises a layer of insulating material (2) the upper edge zone (3) of which has a depression on at least a portion of its length and/or width. At least one roofing material has been applied, optionally glued, on top of the layer of insulating material (2), said roofing material preferably being formed of at least one layer, such as roofing felt. The depth f of the depression of each edge zone (3) is in the range t ≦ f ≦ 4 t, t being the thickness of the layer of roofing material. As a result, the joints between the roofing units are very tight and almost invisible and improved drainage makes the roofing less susceptible to the effects of the weather.

Description: The invention relates to a roofing of the type comprising a plurality of adjoining roofing units and joining means for joining the roofing units wherein each roofing unit comprises a layer of insulating material, the upper edge zone of which has a depression on at least a portion of its length and/or width, at least one layer of top felt being applied on top of the insulating material, the depth f of the depression of each edge zone being in the range of t ≦ f ≦ 4 t, where t is the thickness of a layer of roofing felt, each joining means comprising a long upper strip placed on top of the portion of the top felt which is in the depressed edge zone, the long upper strip stubstantially entirely filling up the broad depressed area formed by the edge zones of the two adjoining roofing units. DE 28 42 347 discloses a roofing unit having a depression at a first edge zone and a projection at a second edge zone. The depression of one roofing unit thus cooperates with the projection of the corresponding adjoining roofing unit. The roofing units are, however, not joined by means of a felt-like material and the joints do not provide adequate drainage in case of a slightly pitched roof. AT-B-343 326 discloses a roofing of the type which comprises a plurality of adjoining roofing units and adjoining means for joining the roofing units, wherein each roofing unit comprises a layer of insulating material, the upper edge zone of which has a depression on at least a portion of its length and/or width. The roofing units may be made of any suitable known materials and may be built up from different layers, for example a sandwich construction with an insulating layer and a waterproofing layer. DE-A-27 37 614 discloses a roofing element consisting of a lower portion of heat insulating material and a layer of bitumen on the top of it. DE-A-20 40 718 discloses units comprising an insulating layer with a bituminous felt overlayer. It is the object of the invention to provide a roofing of the above type where the joints between the individual roofing units are flush with the surface of the roofing units, thereby providing improved drainage, and where the joints are less exposed to the effects of the weather and which have a more pleasant appearance. The roofing according to the invention is characterised in that the top felt extends a distance s into the depressed edge zone, where s is in the range of 0,2 b ≦ s ≦ 0,8 b and b is the width of the depressed edge zone and that each adjoining means besides a long upper strip comprises a long lower strip to be applied in a central zone of the broad depressed area so that said long lower strip together with said long upper strip substantially entirely fill up said depressed area. As a result, the long upper strip of the joining means may substantially flush with the top felt portions in the middle of the roofing units, whereby no recesses are formed in the finished roof surface. Also, no projections are formed which might prevent complete drainage. According to the invention, the layer of top felt may preferably be glued to the top of the insulating material. An embodiment of the roofing according to the invention is characterised in that below the layer of top felt, a layer of under felt is placed. It is thereby possible to exploit the special properties of the individual layers of felt, for instance their waterproofness and low temperature fitness. The insulating layer of each roofing unit may advantageously be made of mineral wool, cellular plastics with open or closed cells or non-flammable materials with cellular structure. It has also proved advantageous that the width b of the depressed edge zone of the roofing unit is in the range 5 cm ≦ b ≦ 40 cm. According to the invention, said long lower strip of the joining means may firstly be glued to the depressed area formed by the edge zones of two adjoining roofing units and whereupon said long upper strip of the joining means is subsequently glued to said long lower strip already laid in the depressed area. As a result, the mounting of the joining means and consequently the entire roofing is thereby facilitated. According to the invention, the long upper strip and the long lower strip of the joining means may jointly advantageously have such thickness that the top surface of the long upper strip substantially flushes with the top surface of the top felt of the central portion of the roofing unit. The invention is described in greater detail below with reference to the drawing, in which Figure 1 is a perspective view of portions of two adjoining roofing units according to the invention prior to the mounting of the joining means, and Figure 2 is a perspective view of a joining means according to the invention. The roofing according to the invention comprises many adjoining roofing units 1, joined mutually by means of joining means 7. Figure 1 shows two roofing units 1 closely abutting each other. Each roofing unit 1 comprises a layer of insulating material 2, the upper edge zone 3 of which is depressed on at least a portion of its length and/or width. At least one layer of roofing felt has been applied, optionally glued, on top of the insulating material. The depth f of the depression of each edge zone 3 is in the range t ≦ f ≦ 4t, where t is the thickness of the roofing felt. In Figure 1 f equals about 2t. In case there are more than one layer of roofing felt, the uppermost layer is the top felt layer 5, and the lowermost layer is the under felt layer 4. If there is only one layer of roofing felt, this is also called the top felt layer. As to the edge zone 3 of the insulating material 2, the top felt layer 5 does not cover this entire zone but only extends a distance s into the zone. s fulfils the requirement 0.2 b ≦ s ≦ 0.8 b, b being the width of the edge zone. Preferably s is in the range between 0.35 b and 0.5 b. Particularly advantageously, s is about 0.4 b. In the case where only one layer of roofing felt is used, the top felt layer 5 extends from the middle portion of the roofing unit 1 and a distance s into the depressed edge zone 3. Here again s is in the range 0.2 b ≦ s ≦ 0.8 b, b being the width of the edge zone. As shown in Figure 2, each joining means 7 comprises a long lower strip 8 as well as a long upper strip 9. The lower strip 8 is to be applied in the central portion of the broad depressed area 10 formed by the depressed edge zones of the two neighbouring roofing units. The long upper strip 9, placed on top of the lower strip 8 and fastened thereto, is to substantially fill up said broad depressed area entirely. The edge portions of the long upper strip are fastened to top felt portions 5a by means of glueing, said top felt portions projecting into the depressed edge zones 3 and thereby into the depressed area 10 formed by said zones. The roofing may be laid on concrete or steel plates (corrugated), plywood or other self-supporting bases in new buildings or when renovating an existing roof. The roofing may be divided longitudinally/transversely, optionally diagonally. Each roofing unit 1 may be bevelled so as to be used on round or lopsided roofs. It has proved practical for the width b of the depressed edge zone 3 of the roofing unit 1 to be in the range 5 cm ≦ b ≦ 40 cm. The edge zones may have depressions in more than the two levels shown. The insulating layer 2 may be made of mineral wool, foamed plastics, cellular plastics, compressed glass particles (Foamglas™) or other heavily insulating material. The insulating material may have open or closed cells. The top felt layer is preferably a roofing felt or a roof membrane of conventional construction with for instance reinforcement material and bitumen with different additives, such as talc, polymerization agent or softener. The under felt layer is preferably of the same structure as the top felt layer. The upper strip 9 and the lower strip 8 of each joining means 7 may be joined, for instance by gluing, to form a unit before being laid into the broad depressed area 10. This is, however, not an absolute necessity. The lower strip may be placed first, followed by the upper strip. The joining means 7 is preferably fastened by means of gluing to the broad depressed area 10. The fastening may also take place by melting which is the most common method. The upper strip and the lower strip of the joining means 7 may not necessarily be of the same thickness. Possibly the thicknesses may be selected in such a manner that the surface of the upper strip 9 projects slightly above the top felt layer 5 of the central portions of the roofing units 1 when the strips have been mounted in the entire depressed area 10. However, in the embodiment shown, the upper strip 9 is flush with the top felt layer 5 on the central portion of the roofing unit 1. The conventional production margin are ± ½ t, corresponding to 4 mm. The protection is not only directed towards the roofing as such but also towards each roofing unit, which will typically have the dimensions 120 x 240 cm. The joining means, which are in the form of strips, extend along the roofing units, for instance along their long side as appears from the drawing. A depressed edge zone with projecting top felt layer and under felt layer may also be provided on the short sides of the roofing units, in the same manner as shown in Figure 1. The invention may be varied in many ways without thereby deviating from the scope of the appended claims.

Claims: Roofing of the type which comprises a plurality of adjoining roofing units (1) and joining means (7) for joining the roofing units (1), wherein each roofing unit (1) comprises a layer of insulating material (2), the upper edge zone (3) of which has a depression on at least a portion of its length and/or width, at least one layer of top felt (5) being applied on top of the insulating material (2), the depth f of the depression of each edge zone (3) being in the range t ≦ f ≦ 4 t, where t is the thickness of the felt, each joining means (7) comprising a long upper strip (9) placed on top of the portion (5a) of the top felt (5) which is in the depressed edge zone (3), the long upper strip 9 substantially entirely filling up the broad depressed area (10) formed by the edge zones of the two adjoining roofing units, characterised in that the top felt (5) extends a distance s into the depressed edge zone (3), where s is in the range of 0,2 b ≦ s ≦ 0,8 b and b is the width of the depressed edge zone (3) and that each joining means besides a long upper strip (9) comprises a long lower strip (8) to be applied in a central zone of the broad depressed area (10) so that said long lower strip (8) together with said long upper strip (9) substantially entirely fill up said broad depressed area (10). Roofing as claimed in claim 1, characterised in that the layer of top felt is glued to the top of the insulating material. Roofing as claimed in claim 1, characterised in that below each layer of top felt (5), a layer of under felt (4) is placed. Roofing as claimed in claims 1, 2 or 3, characterised in that the insulating layer (2) of each roofing unit (1) is of mineral wool, cellular plastics with open or closed cells or non-flammable materials with cellular structure. Roofing as claimed in one or more of the claims 1-4, characterised in that the width b of the depressed edge zone (3) of the roofing unit (1) is in the range 5 cm ≦ b ≦ 40 cm. A method of forming roofing as claimed in claim 1, characterised in that said long lower strip (8) of the joining means (7) is firstly glued to the depressed area (10) formed by the edge zones (3) of two adjoining roofing units (1), and that said long upper strip (9) of the joining means (7) is subsequently glued to said long lower strip (8) already laid in the depressed area (10). Roofing as claimed in one or more of the claims 1-5, characterised in that the long upper strip (9) and the long lower strip (8) of the joining means (7) have jointly such a thickness that the top surface of the long upper strip (9) is substantially flush with the top surface of the top felt (5) of the central portion of the forming unit (1).

Inventors: OLDENBORG BENT, OLDENBORG, BENT
Applicants: PHONIX CONTRACTORS AS, AS PHONIX CONTRACTORS
Application year: 1991
Main classification: E04D3
IPC codes: E04D3