WO2003023163A1

WO2003023163A1 - Metal shingle for roofs

Info

Publication number: WO2003023163A1
Application number: PCT/FI2002/000714
Authority: WO
Inventors: Tuomo Tapani Huopana; Veli-Pekka Vuoti
Original assignee: Rannila Steel Oy
Priority date: 2001-09-10
Filing date: 2002-09-05
Publication date: 2003-03-20
Also published as: FI20011785A; FI20011785A0; FI116858B

Abstract

A modular roof shingle (1) made of metal sheet, whose upper edge (5) comprises an outwardly extending sealing fold and whose lower edge (6) comprises an inwardly extending portion. The first lateral edge (3) and the second lateral edge (4) comprise mutually sealing shapes. The sealing fold of the upper edge comprises a vertical first projection (2a) in the shape range from ⊥ to Λ which continues partly as the surface area (A) of the shingle and partly as the fixing strip (9). The lower edge comprises a leg (10) equipped with a support border (11) and pointing inwardly from the surface area (A), the direction of the leg forming a first angle (α) to the plane direction (T) passing through the concave edge (12) and the support border, the angle opening inwardly at 90 ° to 30 °.

Description

Metal shingle for roofs

This invention relates to a modular roof shingle made of metal sheet, having an upper edge and a lower edge, and a first lateral edge and a second lateral edge: the up- per edge comprising a sealing fold extending outwardly from the outer surface of the shingle and a fixing strip as an prolongation of this; the lower edge comprising a portion extending inwardly from the inner surface and bearing against the region of said sealing fold; and the first lateral edge and the second lateral edge comprising shapes that fit tightly together.

The patent FI-92744 (= EP-0 350 587 B 1) describes a shingle which is substantially rectangular in shape and whose one lateral edge is bent upwardly in the shape of an U and is equipped with an extension at one end, whose opposite lateral edge is bent similarly in the shape of a downwardly directed U, and whose upper transverse edge is bent in an upwardly directed U. Said extension is further placed at the lower end of the second lateral edge and bent as a downwardly directed U so as to be able to engage the fold of the upper transverse edge of the next lower shingle. In this design, the lateral edges of the shingle are thus overlapping with double rebating, i.e. the horizontal leg of the upper U-shape of the second lateral edge passes between the horizontal leg of the lower U-shape of the opposite lateral edge of the adjacent shingle and the remaining area of the shingle. The horizontal joint between the shingles, in turn, is formed of the region of the slightly downwardly tilted transverse edge of the upper shingle fitting against the outer leg, parallel with the roof, of the upwardly bent U-shape of the upper transverse edge of the lower shingle. These shingles are fixed by means of holes in the upwardly directed extensions of the folds of the lateral edges and the U fold of said extension. The manufacture of such a shingle is difficult and entails material loss, and it does not provide good water- proofness considering the effect of winds. The patent US-5 799 460 also describes a solution based on double rebating, in which adjacent shingles are fixed to each other with separate locking strips and the lower transverse edge is bent as a downwardly directed U, thus providing double rebating together with the upwardly bent zigzag shape of the upper transverse edge of the lower shingle. The waterproofness of this structure involves exactly the same problems as that of publication FI-92744.

In the patent US-5 953 810, the vertical lateral edges of the singles are shaped so as to provide double rebating just as in publication FI-92744, however, the lower transverse edges of the shingles are bent downwardly in U-shape while the U-bend of the upper transverse edges is narrower than the U-bend of the lower transverse edges, so that a cavity between the lower and the upper transverse edges is formed in this horizontal double rebating, the cavity preventing wind pressure from pushing water upwards through the joint. In this patent, the U-bend of the upper transverse edges has also been extended with a new, opposite fold extending further upwardly, so that said cavity gets a larger diameter and a nailing edge extending over the entire width of the shingle is obtained. Publication JP- 10-306547 describes also a construction, in which the vertical lateral edges of the shingles are shaped so as to provide double rebating just as in publications FI-92744 and US-5 953 810, but the lower transverse edge and upper transverse edge of the shingle both include a complex shape formed of several folds, so that a cavity is formed in the horizontal joint. These solutions may resolve the problem of sealing horizontal joints between shingles, however, they complicate the manufacture and impair the stacking capability of the shingles. Joints between lateral edges carried out by double rebating further yield a shingle that is difficult to stack and exposed to damage during transport, while the questionable watertightness of the double rebating remains a problem.

The purpose of the invention is thus to provide a modular roof shingle made of metal sheet, i.e. a roof element made of metal, which, on the roof, joins the upper and the lower adjacent shingle, and also laterally the two adjacent shingles on both sides, so that the roof will remain waterproof even under windy and rainy weather conditions. Secondly, shingles shall allow stacking on top of each other as tightly as possible and with a minimum of space loss, so that the shingles require but small space during transport. It is also desirable that the shingles comprise no protrusions, which would be exposed to damage during transport and any other handling opera- tions, and would thus harm at least their installation. Thirdly, shingles should be shapeable so as to adapt to any architectural requirement. Fourthly, the shingle should be economical to produce and suitable for large-scale production methods, such as plate pressing on a modern production line.

The problems described above are resolved and the purposes defined above are achieved by means of a modular metal roof shingle of the invention, which is characterised by the features defined in the characterising clause of claim 1.

The chief advantage of the invention is the good waterproofness of the roof composed of modular shingles of the invention, because overlapping joints act as both horizontal and vertical joints between the shingles, the overlapping joints having trough structures interrupting capillary water, thus also preventing the action of winds on water penetration. A second advantage of the invention is that only shin- gles of the invention are needed for the assembly of the roof, but no supplementary parts such as separate fixing ribs or the like, except for nails and screws, by means of which the shingles are fixed to the roof hangers. A third advantage of the invention is that shingles of the invention can be tightly stacked with a view to transporta- tion.

The invention is described in detail below with reference to the accompanying drawings. For all the features to be included, all of the dimensions and shapes in the figures are not necessarily quite correct and corresponding to reality.

Fig. 1 shows a first embodiment of a modular shingle of the invention consisting of metal sheet, in a general axonometric projection.

Fig. 2 shows a roof assembled of shingles of the type shown in figure 1 in a section parallel with the water flow direction, i.e. often perpendicular to the roof saddle, in plane I-I of figures 1 and 3.

Fig. 3 shows a roof assembled of shingles of the type shown in figure 1 in a section perpendicular to the water flow direction, i.e. often parallel with the roof saddle, in plane II-II of figures 1 and 2.

Fig. 4 illustrates the area of the joint between the upper and the lower shingle in a roof, in the same projection as figure 2 at point III, but on a larger scale. An embodiment corresponding to figure 1 is shown with unbroken lines and the embodi- ment of figure 5 with broken double-dotted lines.

Fig. 5 shows a second embodiment of the modular shingle of the invention made of metal sheet, more specifically the region of the upper edge of the shingle, in a generally axonometric projection.

Modular roof shingles made of metal sheet comprise an upper edge 5 and a lower edge 6, and a first lateral edge 3 and a second lateral edge 4, an upper edge denoting the border area of the shingle located towards the roof saddle in the finally mounted roof, and a lower edge implies the border region of the shingle which is located to- wards the horizontal cornice of the roof in the finally mounted roof, whereas lateral edges, if aligned, are located in alignment with the roof ends in the finally mounted roof. The directions relating to this invention as defined above "upper" and "lower" and "lateral" in the width and length directions Wp and Lp of the shingle are exactly correct when the pane of the roof is rectangular and its saddle is horizontal, and the shingle is also rectangular. It is understood that these definitions apply nearly or at least adapted to situations, where the roof saddle is not horizontal and/or the pane of the roof is not rectangular and/or the shingle is not rectangular. With a general defi- nition, the flow direction of water on the roof is transverse, or typically perpendicular to the upper and lower edges of the shingles, and to some extent parallel with the lateral edges in the "upper"' and "lower" and "lateral" directions. As a general feature, the upper edge of the shingle 1 has a sealing fold extending outwardly from the outer surface 7 of the shingle, and an extending fixing strip 9, and also an portion extending inwardly from the inner surface 8 at the lower edge of the shingle 1. The first lateral edge and second lateral edge of the shingle 1 further comprise mutually sealing shapes. As appearing above, the shingle 1 is typically and most advantageously at least generally rectangular, when viewed in the shape defined by its boundary edges in projection on a plane corresponding to plane direction T defined below, but it may also to some extent have the shape of a trapezium or any other shape. In the thickness direction of the shingle, i.e. roughly perpendicularly to the thickness S of the metal sheet, the "outer surface", the "outer side" and "outwardly" etc. denote the side and direction which, in the finished roof gets in direct contact with rain water or the like, or points to the free environment, and accordingly, the "inner surface", "inner side" and "inwardly" etc. denote the opposite side or direction, which in the finished roof fit against the roof hangers 25 or point towards the region of the roof hangers.

In accordance with the invention, the sealing fold of the upper edge 5 preferably comprises a first vertical projection 2a extending substantially in the range from shape 1 to shape A, which is formed of folds in opposite directions of the metal sheet and continues on the one hand as surface area A of the shingle and on the other hand as fixing strip 9. Surface area A is the area defined by the part L_A of the total length Lp of the shingle which in the finished roof is exposed to weather condi- tions, and by the lateral edges, i.e. the total width Wp of the shingle. The J. shape mentioned in the invention corresponds to the second embodiment and the A shape to the first embodiment. Said one contour shape of the outwardly pointing first projection 2a, i.e. substantially the 1 shape, is shown in figure 5, from which it is understood that it is formed when the metal sheet M continues from the surface area A nearly perpendicularly outwardly, i.e. away from the outer surface 7, as the lower vertical side 16, so that a concave edge 12 is formed at the bend between this vertical side and the surface area, and then after a nearly 180° curve, i.e. a stop edge 20, returns inwardly as rear side 17 and further from the lower edge 22 of the rear side as fixing strip 9 towards the upper edge 5. In this case, the lower vertical side and rear side are both perpendicular, in a given range of variation, either to plane direction T described below or to said surface area A. The fixing strip then continues from the lower edge 22 of the rear side 17 of the first substantially 1-shaped projec- tion 2a principally in the plane direction T. Said second contour shape of the outwardly pointing first projection 2a, i.e. the Λ-shape, is shown in figure 1, from which it is understood that it is formed when the metal sheet M continues from the surface area A in a sharp angle β-φ outwardly, i.e. away from outer surface 7 and in a way also towards the lower edge 6, as lower vertical side 16, so that a concave edge 12 is formed at the bend between this vertical side and the surface area, and then at a sharp angle ω to the plane direction T, i.e. after stop edge 20 directly as a fixing list 9 towards the upper edge 5. It is understood that the first projection 2a may vary in shape between these two alternatives, i.e. the angle β-φ of the lower vertical side 16 to the surface area A or the plane direction T may vary between a sharp angle to a straight angle or a slightly blunt angle, depending on the reference and other shapes, and in addition, the distance between the stop edge 20 and the upper edge 5 may consist either of one single substantially straight fixing strip 9 or a combination of fixing strip 9 and rear side 17, or viewed from the outside, of a concave fixing strip or the like. The latter shape described, i.e. the Λ-shape, in which hence the lower vertical side 16 and the fixing strip 9 form two sides in a triangle supported against the lower edge of the shingle 1, the stop edge 20 being closer to the lower edge 6 than the concave edge 12, is regarded as a more advantageous embodiment at least with respect to its stacking capability and ease of manufacture. More precisely, the lower vertical side 16 of projection 2a described above forms a second angle β to plane direction T explained in the next paragraph, this angle being thus open outwardly as defined above. The angle is maximally 90° and more than 40°. Preferably, the second angle β between the vertical side 16 and the plane direction T is at the most 70° and at least 50°. The vertical side 16 may be straight, as in the figures, or convex or concave, and in that case, the direction of the connecting straight line between the vertical side 16 and the concave edge 12 of the surface area A is regarded as the lateral direction corresponding to the vertical side of the angle β.

The shingle 1 also comprises a vertical second projection 2b extending from the fix- ing strip 9 upwardly in the same direction as the first projection 2a. The shingle is fixed to roof hangers 25 with nails struck or screws screwed through the fixing strip

9 or by corresponding clamps 24. The Λ-shape described above is advantageous be- cause then the clamps 24 clamp the shingle tightly in position against the roof hangers 25.

In accordance with the invention, the lower edge 6 of the shingle 1 comprises a leg 10 pointing inwardly from the shingle surface area A and having a support border 11. Hence the metal sheet M continues at its lower edges as a sharp angle α-φ inwardly from the surface area, i.e. away from the inner surface 8 as the leg 10, which ends in support border 11. More precisely, the main direction of the leg 10 forms a first angle α relative to the plane direction T passing through the support border 11 and the concave edge 12 between the first projection and the surface area, the angle being open inwardly from the lower surface 8 and in a way also towards the upper edge 5. The size of the angle α is 90° at the most and 30° at the least. Hence the plane direction T defined above implies any plane aligned with lines passing through the concave edge 12 and the support border 11, as shown in figures 1 and 2. Preferably, the first angle α between the leg 10 and the plane direction T is 75° at the most, or 60° at the most, and 45° at the least. The downwardly pointing support border 11 of the leg 10 is disposed to bear against the concave edge 12 between the first vertical first projection 2a and the surface area A of the next lower shingle in the assembled roof, as shown in figures 2 and 4. The leg 10 may be straight, as in the figures, or convex or concave, and the direction of the joining straight line of the fold 23 between the leg 10 and the surface area A is considered the lateral direction corresponding to the side of angle α. It should be noted that the surface area A may form angles φ of different sizes in the area of the upper edge 5 and the lower edge 6 of the shingle relative to the direction of the plane direction T or the roof hangers 25.

Further, in the invention, the first lateral edge 3 comprises a first mainly M-shaped shape 13 extending outwardly from the outer surface 7 of the shingle 1 and opening inwardly with the trough portion 15 located outside. In other words, the outermost sides 13a, 13b of the M-shape of the shape 13 rise upwardly from the surface area A, either perpendicularly or most preferably slightly approaching each other, and then the outermost sides 13a, 13b are slightly closer to each other at their external height HI. The trough 15 formed by the interfaces 13c, 13d in the centre of the M- shape produces, in the assembled roof, a drainage trough, which at the same time prevents winds from pressing water against the first lateral edge 3. The second lateral edge 4 comprises a mainly Tl-shaped second shape 14, which extends outwardly from the outer surface 7 of the shingle 1 and opens inwardly, exactly in the same way as the first shape. The outermost sides 14a, 14b of the fl-shape of the second shape rise upwardly from the surface area A, either perpendicularly or most preferably approaching each other slightly, and then the outermost sides 14a, 14b are somewhat closer to each other at their internal height H2. The saddle surface 14c of the second shape 14 may be either straight or outwardly convex. The slightly wedge-like shape of the first and second shape 13, 14 described above allow their easy overlapping both during the assembly of the roof and stacking with a view to transportation. The inner width W2 and height H2 of the second shape 14 are equal to or greater than the outer width Wl and height HI of the first shape 13, and hence, in the roof assembled of shingles, the second shape will be disposed to peripherally cover the first shape, as can be clearly seen in figure 3. Both the first shape 13 and the second shape 14 extend from a point as close as possible to the concave edge 12, in alignment with the first lateral edge 3 and accordingly the second lateral edge 4, to the fold 23. In the same way, the outwardly open trough portion 15 of the first M- shape 13 extends from the first projection 2a or from its side towards the lower edge 6 of the shingle, and in addition, the lower end 15' of this trough portion opens to said surface area A, so that any water flowing downwardly on this may escape. This is achieved with the trough 15 being curved just before the fold 23 as a lower end 15' towards the second opposite lateral edge while the portion of the first shape formed by the outermost side 13a towards this and the intermediate side 14a is low- ered to the same height as the trough bottom 15a.

In the second embodiment of the invention, i.e. using a ±-shape in the first projection 2a, this first projection also comprises at least two catches 19, which form a second angle β relative to the plane direction T passing through the concave edge 12 between the first projection and the surface area and the support border 11, the angle opening outwardly, i.e. away from the outer surface 7 and in a way also towards the lower edge 6, exactly as defined above regarding this second angle. In this case, too, the second angle β is 90° at the most and over 40°, and preferably the second angle β is 70° at the most and 50° at the least. The catches 19 can be made by bending the first projection 2a especially at its stop edge 20 over short width portions R to a suitable extent towards the lower edge 6 of the shingle.

In all of the embodiments of the invention, the first angle α is substantially smaller than said second angle β and the difference β- between the second and the first angle is at least 10° and at the most 50°. Preferably the difference β-α between the second angle and the first angle is in the range 15°...35°. With such dimensioning, in a roof assembled of shingles 1, the lower vertical side 16 will lock, either over its entire length, i.e. the width Wp of the shingle in the first embodiment, or only over the width portions R of the catches 19 in the second embodiment, the leg 10 and thus the lower edge 6 of the shingle into position. Thus, the vertical side 16, i.e. the catches 19 tilting towards the lower edge 6 of the shingle, will extend over the leg 10 pointing inwardly, thus preventing this and the lower edge of the shingle from rising outwardly and from being detached. At the same time, a water-limiting gorge 21 is formed between the lower vertical side and the leg, which prevents winds from propelling water over the stop edge 20. The second projection 2b further enhances this effect.

Regarding the remaining shape and dimensioning of the shingle 1 of the invention, we note that the projection height H3 perpendicular to the plane direction T of the first projection 2a is smaller than the leg height perpendicular to the plane direction T of the leg 10, so that, in the mounted roof, the support border 11 of the leg 10 bears tightly against the concave edge 12 as intended. The surface portion of the surface area A, which is located partly between the fold 23 between the leg 10 and said surface area and the concave edge 12, and partly between the first shape 13 and the second shape 14, may be even,, as shown in figures 2 and 3, or comprise any desired shape, as shown in figure 1. In this context, aesthetic and appearance aspects can be quite freely taken into account. The material used in the shingle may be any suitable metal having adequate thickness, strength properties and shaping properties, such as steel sheet, aluminium sheet or copper sheet. The metal sheet may be coated or uncoated.

The design and shape of the invention achieve the intended advantages without any notable inconveniences. When completed, the roof is wateφroof and the shingles can easily be piled and transported, and it has economical production and easy assembly. The manufacture may take place e.g. by roll shaping first the shapes relating to the upper edge 5 and the lower edge 6, i.e. the leg 10, the first projection 2a, the second projection 2b and the fixing strip 9 between these, on a continuous metal sheet web, by subsequently punching alternating first shapes 13 and second shapes 14 at predetermined locations and by finally cutting shingles from the web along lines transverse to the roll-shaped edges and aligned with said shapes. Then the first lateral edge and the second lateral edge are advantageously mutually substantially aligned. The first embodiment in particular is advantageous for stacking, because in stacks, its shingles only require a space S equalling their material thickness S in the vertical direction. The substantially inwardly directed leg 10 at the lower edge 6 of the shingle is primarily either planar or curved, e.g. downwardly convex or concave, yet at least almost straight parallel to the fold 23. In the case of a curved leg, the first angle α implies the mean angle, i.e. the angle formed by the span between the end points of the leg. The support border 11 mentioned above forms a part of this leg, and does not typically comprise any additional folds, the leg 10 including its support border 11 being in its totality advantageously either planar or monotonously curved. The support border may, of course, comprise a small fold, e.g. a rounded edge or the like if desired, the thickness of the fold in the longitudinal direction L_p of the shingle being less than 20% or typically less than 10% and preferably less than 5% of the dimension of the leg 10 in this same direction, yet such folds do not have any additional impact on the mounting of the shingle of the invention or is function in the completed roof, but rather complicate the manufacture. At the upper edge 5 of the shingle, said opposite folds with a -shape or an Λ-shape or any intermediate shape, as mentioned above, are substantially located in outwards and downwards directions, however, only downwardly equalling the inclination generated by the angle β, otherwise the metal sheet M forming the shingle continues from the surface area A as a first projection 2a and from there on upwards as a second projection 2b. Thus the upper edge 105 of the metal sheet and also the second projection 2b extend substan- tially upwardly from the first projection 2a, more precisely the sheet upper edge 105 and the second projection 2b extend upwardly from the first projection 2a over a dimension L_C±Λ. This dimension L_C±Λ also equals the width of the fixing strip 9 in the longitudinal direction L_p of the shingle, and the variation range Δ of the dimension depends i.a. on any inclination of the second projection and the shape of the fixing strip proper. In the finished roof, the second shape 14 of the second lateral edge 4, which consequently has an inwardly opening groove aligned with the lateral edge, fits on top and around the first shape 13 of the first lateral edge 3, which thus is an outwardly pointing elevation with an inwardly pointing drainage trough 15. The shingles 1 of the invention are mounted starting from the cornice as follows: the first row of shingles is arranged and fixed with their second lateral edges horizontally overlapping as described above on top of the first lateral edges and from the outside, and then a second row of shingles 1 is mounted from the outside with their lower edges 6 vertically overlapping with the upper edges 5 of the first row of shingles, at the same time as the second lateral edges in this row horizontally overlap the first lateral edges. The process is continued in this way to the roof saddle.

Claims

1. A modular roof shingle made of metal sheet, having an upper edge (5) and a lower edge (6) and a first lateral edge (3) and a second lateral edge (4); the upper edge comprising a sealing fold extending outwardly from the outer surface (7) of the shingle (1) and an prolonging fixing strip; the lower edge comprising a portion extending inwardly from the inner surface (8); and the first lateral edge and the second lateral edge comprising mutually sealing shapes, characterised in that the sealing fold of the upper edge (5) comprises a vertical first projection (2a), which is sub- stantially in the shape range from ±-shape to Λ-shape and which is formed of recip- rocatively directed folds in the metal sheet and continues partly as a surface area (A) of the shingle and partly as a fixing strip (9); that the lower edge (6) comprises a leg (10) pointing inwardly from the surface area of the shingle and having a support border (11); and that the main direction of the leg (10) forms a first angle (α) in re- spect to a plane direction (T) passing through the support border (11) and the concave edge (12) between the first projection and the surface area, the angle opening inwardly from the inner surface (8) and being less than 90° and at least 30°.

2. A shingle as defined in claim 1 , characterised in that the first angle (α) between the leg (10) and the plane direction (T) is at the most 60° and at least 45°.

3. A shingle as defined in claim 1, characterised in that the inwardly pointing support border (11) of the leg (10) is disposed to bear against the concave edge (12) between the vertical first projection (2a) and the surface area (A) of the next lower shingle.

4. A shingle as defined in claim 1, characterised in that it further comprises a vertical second projection (2b) prolonging from the fixing strip (9) outwardly in the same direction as the first projection (2a).

5. A shingle as defined in claim 1, characterised in that the first lateral edge (3) comprises a mainly M-shaped first shape (13) extending outwardly from the outer surface (7) of the shingle (1) and opening inwardly with a trough portion (15) located outside; and that the second lateral edge (4) comprises a mainly U-shaped second shape (14) extending outwardly from the outer surface (7) of the shingle (1).

6. A shingle as defined in claim 5, characterised in that the inner width (W2) and height (H2) of the second shape (14) are equal to or larger than the outer width (Wl) and height (HI) of the first shape (13), so that, in the roof assembled from shingles, the second shape covers the first shape peripherally.

7. A shingle as defined in claim 1, characterised in that the lower vertical side (16) of the first projection (2a) forms a second angle (β) in respect to the plane direction (T) passing through the support border (11) and the concave edge (12) between the first projection and the surface area, the angle opening outwardly from the outer surface (7) and being at the most 90° and more than 40°.

8. A shingle as defined in claim 7, characterised in that the second angle (β) between the vertical side (16) and the plane direction (T) is at the most 70° and at least 50°.

9. A shingle as defined in claim 1, characterised in that the first projection (2a) be- ing substantially .L-shaped, its lower vertical side (16) and rear side (17) are both peφendicular in a given variation range either to said plane (T) or to said surface area (A); and that the first projection (2a) comprises at least two catches (19), which form a second angle (β) in respect to the plane direction (T) passing through the support border (11) and the concave edge (12) between the first projection and the surface area, the angle opening outwardly from the outer surface (7) and being at the most 90° and more than 40°.

10. A shingle as defined in claim 9, characterised in that the second angle (β) between the catches (19) and the plane direction (T) is at the most 70° and at least 50°.

11. A shingle as defined in claim 7 or 9, characterised in that said first angle (α) is substantially smaller than said second angle (β); and that the difference (β-α) between the second angle and the first angle is at least 10° and at the most 50°, or preferably in the range 15° to 35°, so that, in the roof assembled of shingles, the lower vertical side (16) locks the leg (10) and thus the lower edge of the shingle into position, and a water-limiting gorge (21) being formed between the lower vertical side and the leg.

12. A shingle as defined in claim 1, characterised in that the fixing strip (9) contin- ues:

- substantially from the lower edge (22) of the rear side (17) of the first l-shaped projection (2a) principally in the plane direction (T); or - substantially from a stop edge (20) of the Λ-shaped first projection (2a), forming an angle (ω) to the plane direction (T).

13. A shingle as defined in claim 5, characterised in that the outwardly open trough portion (15) of the M-shaped first shape (13) extends from the first projection (2a) or from beside it towards the lower edge (6) of the shingle, and the lower end (15 of this trough portion opens to said surface area (A).

14. A shingle as defined in claim 1 or 11, characterised in that the projection height (H3) of the first projection peφendicular to the plane direction (T) is smaller than the leg height (H4) of the leg (10) peφendicular to the plane direction (T).