EP0138561B1

EP0138561B1 - Roof space ventilation

Info

Publication number: EP0138561B1
Application number: EP19840306884
Authority: EP
Inventors: Leslie Gerald Hammond; John Alfred Fifield
Original assignee: Anchor Building Products Ltd
Current assignee: Anchor Building Products Ltd
Priority date: 1983-10-10
Filing date: 1984-10-09
Publication date: 1990-04-04
Anticipated expiration: 2004-10-09
Also published as: IE55710B1; GB2147992A; GB2147992B; EP0138561A3; EP0138561A2; GB8425493D0; DE3481853D1; GB8327067D0; IE842576L

Description

This invention relates to the ventilation of pitched roof spaces and more particularly to high-level roof ventilation.
Roof ventilation is essential in pitched roof spaces in order to control condensation which, if permitted to occur can result in mould growth, rot and distortion of roof timbers, metal corrosion, ceiling damage and reduced thermal insulation. In principal, the most effective way of ventilating a pitched roof space is known as eaves to ridge ventilation which involves a flow of air into the roof space from the low level of the eaves to the high level of the ridge. The object of eaves to ridge ventilation is to achieve adequate ventilation whatever the wind direction, convectional ventilation in windless conditions, satisfactory mixing of air throughout the roof space and uniform outflow of air from the roof space.
It is an object of the present invention to provide an improved system for high-level pitched roof space ventilation.
From one aspect, the present invention consists in a ventilation member for use in the ventilation of a pitched roof space, said ventilation member being adapted to rest on and extend transversely of the upper surface of a roof covering, and having an upper wall for supporting at least a portion of a longitudinal side edge of a ridge covering, an open-bottom, a front wall depending from the upper wall and defining an elongate ventilation area which is disposed to extend transversely of the roof covering and which comprises a plurality of ventilation apertures having a size to prevent the entry of large insects into the ventilation member and thus into a roof space and yet permit a sufficient volume of air to pass therethrough, a baffle depending from the upper wall and spaced from said front wall and said open bottom, for creating a reduction in pressure of any wind blowing into the ventilation member through the ventilation apertures and for precipitating wind driven water through said open bottom and onto said roof covering, and a ventilation opening located above said open bottom and behind said baffle for permitting a flow of air from the roof space into the ventilation member, around said baffle and out through said ventilation apertures.
By means of the invention, a substantially continuous area of ventilation along the length of a roof ridge is achieved, ensuring sufficient volume of air flow through and out of the roof space whatever the wind direction and in windless conditions, the apertures of the elongate ventilation area are of such a size as to prevent the entry of large insects into the roof space yet ensure adequate air flow and the baffle reduces any wind pressure. The ventilation member constructed according to the present invention can be made in one-piece e.g. a one-piece plastics moulding, and is simple to fit in that it can accommodate variations in the laying of the tiles.
The ventilation area preferably has the configuration of a grille, with the apertures being elongate in form and extending transversely of the direction of the grille.
In a preferred embodiment, the front wall has a lower edge having the general shape of the nib of the particular roofing tile with which the ventilation member is to be used in the case of contoured roofing tiles or is flat or straight in the case of plain tiles. By making the ventilation member with a front wall of such shape, there is no difficulty in fitting them to a roof where the tilers have not kept the fixing of each line of tiles the same.
Advantageously, there is a rear wall depending from the upper wall behind the baffle and defining therewith an open-bottomed rear chamber portion with which the ventilation opening is in communication. Preferably, the rear wall extends downwardly for a greater distance than the front wall so as to engage against the top edge of a roofing tile of the upper-most tile course to hold the ventilation member thereon. If desired the rear wall could be extended still further to permit the tiling member to be nailed to the top tiling batten through the further extension to prevent it being blown inwards by strong winds and/or stop a flow of air into the tiling member from between the roof felt and roofing tiles. Conveniently, the lower edge of the rear wall has a shape which is generally the same as the lower edge of the front wall.
In a preferred embodiment, the rear chamber portion has a greater size than that of an open-bottomed front chamber portion defined by the upper wall, the front wall and the baffle which extends downwardly for a lesser distance than the front wall to permit a flow of air around the baffle and out of the ventilation apertures.
In order to provide for the option of having a secondary water check in the form of a water proof membrane passed over the ridge batten and onto the upper wall portion, where the longitudinal ridge of a ridge tile would rest on the membrane, the ventilation opening opens into the rear chamber portion from the upper wall and has a hood or cowl to prevent the membrane closing the ventilation opening. Alternatively, the ventilation opening could be in the rear wall behind the baffle.
Additionally or instead of the further extension of the rear wall, the upper wall may have a plurality of spaced apart stops or projections extending along its front edge to guard against the possibility of the ventilation member being blown inwards by strong winds.
Preferably, the ventilation member has support elements extending transversely thereof and in the direction of a roofing tile when laid thereon and which engage with, and further support, the ventilation member on the upper surface of a roofing tile and ensure that the ventilation members adequately support the ridge tiles, particularly in the case of contoured roofing tiles having shallow pans and with plain tiles.
In the case of contoured roofing tiles of the bold roll type which have deep pans, the apertured ventilation area preferably lies substantially in the pan when the ventilation member is laid thereon but, in the case of shallow panned contoured roofing tiles and plain roofing tiles the ventilation area preferably lies above the pan and the top surface of the roofing tile.
From another aspect the present invention consists in a pitched roof structure comprising a plurality of roofing tiles laid in courses on roof battens, and a plurality of any of the ventilation members as defined hereinabove resting on roofing tiles of the or each uppermost course with the apertured ventilation area facing outwards.
In dual pitch and mono-pitch roof structures, the roof structure includes a plurality of ridge tiles arranged in end to end relationship along the roof ridge with the longitudinal side edges of the ridge tiles resting on the upper portions of the ventilation members on opposite sides of the roof apex with dual pitch roofs, and with mono-pitch roofs the ridge tiles are half ridge tiles and one of their longitudinal side edges rests on the upper walls of the ventilation members.
In the case of roof structures terminating at an abutment wall, ridge tiles are not used and the ventilation members will be at the top of the roof and can easily be held in position by a clip and/or flashing and/or by nailing the further extension of the rear wall, if provided.
In order that the invention may be more readily understood, some embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a front elevation of one embodiment of ventilation member constituted by a tiling member constructed in accordance with the invention,
Figures 2 and 3 are a cross-section and a plan view respectively of the tiling member of Figure 1,
Figure 4 is a perspective view of a part of a tiled roof structure showing the tiling members of the embodiment of Figures 1 to 3 in position.
Figure 5 is a cross-section through the ridge of the tiled roof of Fig. 4.
Figure 6 is a front elevation of another embodiment,
Figures 7 and 8 are a cross-section and a plan view respectively of Figure 6,
Figures 9 and 10 are cross-sections of modifications of the embodiments of 1 and 6 respectively.

In the drawings, the same reference characters are used to designate the same or similar parts.
Referring to Figs. 1 to 3 of the drawings, a tiling member which is generally indicated at 1 may be made of any suitable material such as plastics, metal or a cementitious material but is preferably a one-piece plastics moulding, conveniently of polyethylene or polyvinyl chloride, and comprises an upper wall 2 forming a platform. Depending generally perpendicularly from the platform 2 are parallely extending front and rear walls 3 and 4 which, with the platform define an open-bottomed chamber 5. The front wall is formed with an elongate apertured ventilation area 6 which can extend up to the entire length of the front wall 3 and comprising a plurality of vertically arranged transversely extending ventilation apertures 7 to form a ventilation grill. In order to reduce the pressure of air flow due to wind into the tiling member 1 and thus into the roof space, and also to guard against the entry of wind driven water into the roof space, the chamber 5 is divided into front and rear portions 5a and 5b respectively by a baffle 8 depending from the platform 2 and extending parallel to the walls 3 and 4 behind the apertured ventilation area 6.
This embodiment is for use with contoured roofing tiles of double channelled configuration with shallow pans. The bottom edge 9 of the front wall 3 is contoured to match generally the shape, of the tile nib (not shown) so that the tiling member can fit loosely into the tile pan areas and thus accommodate variations in the laying of the roofing tiles. The bottom edge of the rear wall 4 is also contoured to be of similar shape and projects downwardly for a greater distance than the front wall 3 to provide a holding portion 10 which engages with the upper edge of the roofing tile when laid thereon and prevents the tiling. member from slipping down the roof. The front and rear wall 3 and 4 are joined by transversely extending support members in the form of strips 11 having straight bottom edges which engage with the top surface of the contoured roofing tile to ensure that the tiling member takes the weight of the ridge tiles. Alternatively, the transversely extending support members could be in the form of rows of projections or pegs. The support members 11 are of particular importance with plan or flat tiles for preventing collapse of the tiling member.
Air from the roof space flows into the tiling member 1 through an elongate entry opening 12, in and extending lengthwise of, the platform 2 and opens into the rear portion 5b of the chamber 5. The opening 12 is provided with a cowl or hood 13 for a purpose to be described. A row of ridge tile stops 14 constituted by projections or pegs project upwardly from the platform 2 along its front edge for guarding against the possibility of the tiling member being blown inwards for a sufficient distance to prevent it being weatherproof.
Referring now to Figs. 4 and 5, the ridge portion of a tiled dual pitch roof structure comprises spaced apart pairs of wooden rafters 15 to which are secured roof battens 16 with roofing felt 16a laid therebetween. Figures 4 and 5 show the upper courses of concrete roof tiles 17 laid on the battens 16 with the nibs at their upper edges fitted over the battens. At the apex of the rafters 15 are secured, at spaced apart intervals, supporting brackets such as 18 for a ridge batten 19 to which the ridge tiles such as 20 are nailed by nails (not shown). The opposed ends of the ridge tiles 20 may be joined by concrete, or, preferably, (not shown) opposed ends of the ridge tiles are secured together by fixing or jointing members such as are described in the specification of our co-pending British Patent Application No. 8414440 to form a "dry" ridge system. The roofing tiles 17 are of double-channelled .configuration with shallow pans and interlock along their side edges. As will be more readily apparent from Figure 5, the tiling members 1 are laid in position on the upper surfaces of the upper portions of the roofing tiles 17, one for each roofing tile, with the contoured lower edges of the front wall 3 engaging with the pan and top surfaces of the roofing tiles with their holding portions 10 engaging with the upper edges of the top courses of the roofing tiles to hold the tiling members in position. The ridge tiles 20 are then laid over the ridge so that their longitudinal side edges engage with the platform 2 of the tiling members 1 on opposite sides respectively of the ridge between the hoods 13 and the ridge tile stops 14. As will be apparent from Figure 4, the support members 11 rest on the flat top surface of the roofing tiles 17. As the ridge tiles are laid in position, the fixing members can be fitted onto the adjacent ridge tile ends and the ridge tiles 20 are nailed onto the ridge batten 19.
Referring to Figures 2, 4 and 5, the tiling members 1 provide for high-level ventilation of the roof space 21 such that there is a flow of air as indicated by the dashed line 22 in the direction of the indicated arrows out through the gaps between apex of the rafters 15 and upper edges of the roofing tiles 17, through the entry openings 12 of the chamber 5 around the baffle 8 and out through the apertured ventilation area 6. The wind pressure on the right hand side of the tiled structure as illustrated in Figure 5 will produce a low pressure area on the left hand side of the roof which induces a flow of air out through the tiling members 1 on the left hand side of the roof structure as indicated by the dashed line 22.
Wind tests have been carried out by the Applicants with simulated wind speeds of up to 60 mph (96.54 kmh) and it has been found that when air flows through the ventilation apertures 7 in the direction indicated by the arrowed dashed line 23 (see Fig. 2), the baffle 8 acts to reduce the pressure due to wind in the rear chamber portion 5b as evidenced by pressure readings taken therein. Moreover, when water was entrained in the air flow in such tests, the baffle 8 prevented the entry of such wind driven water, not only into the chamber portion 5b but also into the roof space 21.
The hood 13 serves to prevent closing of the opening 12 in the event of using a secondary water check, as indicated by the dashed lines 23a in Figure 5. This water check 23a consists of a waterproof membrane and passes over the ridge batten 19 and underneath the longitudinal side edges of the ridge tiles 20 where they rest between the tile stops 14 and the hood 13. The hood 13 also serves to deflect the air flow from the roof space into the tiling member. By providing the entry opening 12 in the platform 2 the effect of the baffle 8 is enhanced.
It is a simple matter to adapt the embodiment of Figs. 1 to 3 for use with flat or plain roofing tiles by making the bottom edge of the front wall 3 of the tiling member 1 straight as indicated by the chain lines 24 (Fig. 1) instead of contoured. In such a case the bottom edge of the rear wall 4 is also conveniently made straight as indicated by the chain lines 25 in Fig. 1.
The embodiment of Figs. 6 to 8 differs from that of Figs. 1 to 3 in that the tiling member 1a is specially adapted for a deep pan bold roll contoured roofing tile and has front and rear wall walls 3 and 4 of greater depth (compare Figs. 2 and 7) to accommodate the deeper pan with the apertured ventilation area 6 being disposed in the pan between the roofing tile rolls when positioned thereon, whereas in Figs. 1 to 3 the ventilation area 6 is disposed above the pans and top surface of the roofing tiles as will be apparent from Fig. 4. The requisite volume of air flow from the roof space is provided by increasing the length of ventilation, apertures 7. Other differences are that two support members 11 only are provided which rest against the tile pan and which are cut away as indicated at 11a to provide a facility for accommodating a transverse raised barrier on the upper end portion of a roofing tile. The support members 11 in this embodiment could, however, be dispensed with.
In the modifications of Figures 9 and 10, a substantial part of the upper wall 2a is of arcuate, outwardly curved, configuration as viewed in cross-section and extends upwardly and rearwardly at an angle of greater than 90° from the front wall 3 (unlike the upper wall 2 which is at an angle of about 90° to the front wall 3) and stops short of the rear wall 4 so that the ventilation opening is defined between the rear edge of the upper wall 2a and front edge of the remaining flat portion 2b of the upper wall 2 which extends at an angle of about 90° to the rear wall 4. Alternatively, the upper wall 2a is flat. Such modifications are particularly suitable for tapered ridge tiles. By modifying the tiling members 1 and 1a in this way the upper wall 2a also serves the function of the cowl or hood 13. Preferably, as shown, an additional baffle 8a depends from the upper wall 2a for facilitating the flow of air into the tiling member and for preventing blow through from the exterior.
Referring again to Figure 5, tiling members constructed in accordance with the invention also provide for a flow of ventilating air from between the roofing felt 16a and the roofing tiles 17 and into the tiling members 1, (1a) as shown in arrowed dashed lines 30. If desired the rear wall 4 may be extended still further so that its bottom edge engages with the roofing felt 16a to stop this flow of air. The further extension of the rear wall also or instead permits nailing of the tiling member to the top tiling batten 16.
In other embodiments which are not illustrated, the tiling members such as previously described instead of being in one piece may be made in two or more elongate elements which are positioned in correct relationship to one another in situ on the roof or are fitted together either in situ or before laying e.g. by means of inter-engaging members such as projections and apertures or recesses, to form the complete tiling member. In such embodiments, the elongate elements may extend over one or preferably several roofing tiles, and be as long, for example, as 3 metres. In one form of tiling member made of three such elements, these elements could comprise the upper wall, the rear wall and the front wall. In such embodiments the elongate apertured ventilation area could be continuous.
It should be understood that the term tiling, member is used herein in a generic sense to cover a ventilation member which can be used with all types of pitched roof coverings which need not necessarily be ridge and roofing tiles. For example, the ridge covering could be say a plastics elongate ridge covering extending over several normal tile widths and the roof covering instead of being of roofing tiles could be of shingles, slates or of panels e.g. of a suitable metal such as aluminium which may be coated, or of asbestos, and which may be flat, corrugated, or contoured to give an appearance of contoured roofing tiles. Such panels may be 3 x 6 metres, for example. Thus, "ridge tiles" and "roofing tiles" are used herein in a generic sense to cover all kinds of ridge and roof coverings used for pitched roofs.
The elongate ventilation apertured area can extend for any suitable distance up to the full width of a roofing tile. Instead of the vertically arranged apertures 7, the ventilation apertures may be in the form of elongated narrow slots or slits arranged one above the other and extending lengthwise of the ventilation area 6.
Particularly in the case of flat or plain roofing tiles, the tiling members may extend over at least two roofing tile widths.

Claims

1. A ventilation member for use in the ventilation of a pitched roof space, said ventilation member being adapted to rest on and extend transversely of the upper surface of a roof covering, and having an upper wall (2) for supporting at least a portion of a longitudinal side edge of a ridge covering (20), an open-bottom, a front wall (3) depending from the upper wall (2) and defining an elongate ventilation area (6) which is disposed to extend transversely of the roof covering and which comprises a plurality of ventilation apertures (7) having a size to prevent the entry of large insects into the ventilation member (1 or 1a) and thus into a roof space (21) and yet permit a sufficient volume of air to,pass therethrough, a baffle (8) depending from the upper wall (2) and spaced from said front wall (3) and said open bottom, for creating a reduction in pressure of any wind blowing into the ventilation member (1 or 1 a) through the ventilation apertures (7) and for precipitating wind driven water through said open bottom and onto said roof covering, and a ventilation opening (12) located above said open bottom and behind said baffle (8) for permitting a flow of air from the roof space (21) into the ventilation member (1 or 1a), around said baffle (8) and out through said ventilation apertures (7).

2. A ventilation member as claimed in claim 1. wherein the elongate ventilation area has the configuration of a grille (6) with the ventilation apertures (7) being elongate in form and extending transversely of the direction of the grille.

3. A ventilation member as claimed in claim 1 or 2, wherein the front wall (3) has a lower edge having the general shape of the nib of a contoured roofing tile with which the ventilation member (1 or 1a) is to be used or the lower edge (24) of the ventilation member is flat or straight for use with flat or plain tiles.

4. A ventilation member as claimed in any one of claims 1 to 3, and having a rear wall (4) depending from the upper wall (2) behind said baffle (8) and defining therewith an open-bottomed rear chamber portion (5b) with which said ventilation opening (12) is in communication.

5. A ventilation member as claimed in claim 4, wherein the rear chamber portion (5b) has a greater size than that of an open-bottomed front chamber portion (5a) defined by said upper wall (2), said front wall (3) and said baffle (8).

6. A ventilation member as claimed in claim 4 or 5, wherein said ventilation opening (12) is located in said rear wall (4).

7. A ventilation member as claimed in claim 4 or 5, wherein said ventilation opening (12) is located in said upper wall (2).

8. A ventilation member as claimed in claim 7, wherein said ventilation opening (12) is provided with a hood or cowl (13).

9. A ventilation member as claimed in claim 8, wherein the hood or cowl (13) is integral with the upper wall (2) and extends upwardly and over said ventilation opening (12).

10. A ventilation member as claimed in any one of claims 4 or 9, wherein the rear wall (4) extends downwardly for a greater distance than the front wall (3) so as to be engageable against the top edge of a roofing tile of the uppermost tile course to hold the ventilation member (1 or 1a) thereon.

11. A ventilation member as claimed in claim 10, wherein the rear wall (4) is extended still further to permit the ventilation member (1 or 1a) to be nailed to the top tiling batten through the further extension (10) and/or to enable a flow of air into the ventilation member from between roofing felt (16a) and the roofing tiles (17) to be stopped.

12. A ventilation member as claimed in claims 3 and 4 or any dependent thereon. wherein the lower edge of the rear wall (4) has a shape which is generally the same as the lower edge of the front wall (3).

13. A ventilation member as claimed in any one of claims 1 to 12, wherein the upper wall (2) is disposed at an angle of about 90 with respect to the front wall (3).

14. A ventilation member as claimed in anyone of claims 1 to 13. wherein the upper wall (2) has a plurality of spaced apart stops or projections (14) extending along its front edge to guard against the possibility of the ventilation member (1 or 1a) being blown inwards by strong winds.

15. A ventilation member as claimed in any one of claims 1 to 14. and having support elements (11) extending transversely thereof and in the direction of a roofing tile (17) when laid thereon and which engage with, and further support, the ventilation member (1 or 1a) on the upper surface of the roofing tile (17).

16. A ventilation member as claimed in claims 3 and 4 or any claim dependent thereon, wherein a substantial part of the upper wall (2) is inclined at an angle of more than 90 with respect to the front wall (3) and extends upwardly and rearwardly from the front wall towards the rear wall (4).

17. A ventilation member as claimed in claim 16 wherein a substantial part of the upper wall (2) is of outwardly curved form.

18. A ventilation member as claimed in claim 16 or 17. wherein an additional baffle (8a) depends from the upper wall (2) at a location which is behind, and spaced from, the said baffle (8).

19. A ventilation member as claimed in any one of claims 1 to 18, and made of at least two elongate elements which can be positioned or fitted together.

20. A ventilation member as claimed in claim 19 and which extends over several tile widths.

21. A ventilation member as claimed in claim 19 or 20, wherein the elongate elements are fitted together by means of inter-engaging projections and apertures or recesses.