GB2334977A

GB2334977A - Roof ventilation system

Info

Publication number: GB2334977A
Application number: GB9804862A
Authority: GB
Inventors: David Christopher Humphries
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-03-06
Filing date: 1998-03-06
Publication date: 1999-09-08
Also published as: GB9804862D0; GB9810135D0

Abstract

To ventilate the space under a flat or pitched (112) roof extending from a wall (16), an apertured support structure for positioning flashing (124) comprises a fixing part (120) together with an integral, (Fig 4, not shown), or, as shown, a separate, flashing support (122). The apertures (121) are formed in an outwardly-extending part of the support, and the support (122) has a downwardly-extending skirt (142), which is also apertured, (154, Fig 4) for fixing purposes, when the support has only one part. Air passes through a gap (117), and then, optionally, through tile fillers (130).

Description

2334977 1 ROOF VENTILATION SYSTEM The current invention relates to a roof

ventilation system, in particular to a lean-to or flat roof ventilation structure which can be easily secured to a supporting wall.

Modern housing projects are currently required to meet specific environmental and structural standards.

This raising of standards has resulted in an increase in the amount of insulation and draught proofing systems being installed in new and existing property, with special attention being given to the roof structure.

However, a lack of sufficient ventilation in a heavily insulated roof space can lead to condensation. Condensation is prevalent wherever warm air comes into contact with cold surfaces and can cause lasting damaging effects on timber, metal components, electrical equipment, possessions stored in the roof space and decoration below ceiling level.

It is therefore essential that roofs are constructed and replaced with adequate air circulation throughout the roof cavity. This requirement applies equally 'to standard gabled roofs, flat and lean-to roof structures.

i:\intprop\patents\p70699gb - 5.3.98 2 The current application is concerned primarily with the installation of adequate roof ventilation systems for lean-to and flat roofs.

There are currently several methods of securing flat and abutting roof structures to supporting walls, which provide adequate air circulation and conform to relevant British Standards.

Marley@ Building Materials Limited and Glidevale@ Building and Products Limited both provide ventilation systems for lean- to and flat roofs which are completely weatherproof and provide air channels from the roof space to the supporting wall.

The Marleyg Top Abutment Ventilation System employs a channel shaped tile retainer connected to the roof rafters near, but not touching the supporting wall. Air is permitted through the space between the channel and wall and through slots in the top surface of the channel. Above the channel is a flashing support clipped on a top front lip of the channel and leaning against the wall. A filter, shaped according to the tile profile, is inserted under the lip of the channel and against the tiles to prevent ingress of vermin while permitting the passage of air. Fixing the channel to the rafters can pose some difficulties. Moreover, it is not suitable for flat roofs.

i:\intprop\patents\p706999b - 5.3.98 3 The Glidevale(P f lat roof ventilation system requires a number of spaced vertical battens f ixed to the wall immediately above the roof structure, a board covering the battens and defining a number of channels against the wall communicating with the roof space. L-shaped ventilators are fixed to the board and flashing covers them to render the system water proof while still leaving an air gap over the final roof surface. Such a system is quite complex to assemble.

It can be seen from the prior art ventilation systems described above that the current methods for constructing such systems involve various stages, have many parts and are time consuming and hence costly to install.

It is therefore the object of the present invention to provide a lean-to or flat roof ventilation system which provides air circulation within the roof space, yet is of simple construction, easy to install and therefore cost effective.

The system should be designed to permit sufficient air flow to the roof cavity to comply with current ventilation standards, whilst preventing the entry of large insects, birds or vermin.

i:\intprop\patents\p706999b - 5.3.98 4 In accordance with the present invention there is provided a roof ventilation system for a roof abutting a wall and having a roof space the system comprising a ventilator adapted to be fixed to the wall above the roof to define an air gap between the wall and ventilator, the ventilator comprising a support structure for fixing to the wall and a cover extending from the support structure and adapted to support the flashing, windows formed in the support structure to permit the passage of air from the roof space, through the ventilator and out between the roof and the flashing.

1 One of the main advantages of the current invention over the prior art, is the ability to be able to access and replace worn or damaged parts of the ventilation system by simply removing the flashing and releasing the cover form the support structure.

This is in contrast to current systems in which the tiles are an integral part of the ventilation mechanism and are secured to or by the system. Consequently, removal of the ventilation system can lead to damage of the roof tiles or slates thereby increasing the repair or installation time.

The invention is further described hereinafter with reference to the accompanying drawings which show i:\intprop\patents\p706999b - 5.3.98 specific embodiments and which are given as non-limiting examples:

Figure 1 is a side view of a f irst embodiment of a roofing ventilation system in accordance with the present invention for a lean-to, sloping roof; Figure 2 is a perspective cut-away view of the roofing system of Figure 1; Figure 3 is a side view of the same embodiment of the present invention for use in the construction of a flat roof; and Figure 4 is a perspective, cut-away view of an alternative embodiment of the invention.

In figure 1, there is shown a side view of a lean-to roof ventilation system 100 according to the present invention for an abutting or lean-to sloping roof structure.

AS is well known, roofing felt 127 is laid on rafters 112 before roof battens 128 are fixed in place serving to retain the felt. A gap 117 is left between the wall and felt 127.

i:\intprop\patents\p70699gb - 5.3.98 6 Directly above gap 117 and the end of raf ters 112 where they join supporting wall 116, wall battens 118 (spaced evenly apart along the length of the roof) are secured to the supporting wall 116 by suitable attachment means (for example bolts). An extruded plastics ventilation support structure 120 is secured to the wall battens 118 by pins 133.

I Roof tiles or slates 126 are then secured to rafters 112, by means of the roof battens 128. The rafters 112 are secured to supporting wall 116 by means of rafter supports 114 and the tiles or slates are laid sequentially along the length of the rafters up to the supporting wall with the tile or slate closest to the wall 116, being secured last. The tiles 126, are secured to the roof by the roof battens 128 and for example (aluminium) pins (not shown) which pass through the tiles 126 and into the roof batten 128.

An extruded plastics ventilation cover 122, clips over a protruding round section 123 of the ventilator support 120, the ventilation cover 122 forming a base for apron flashing material 124, such as lead.

The ventilation support structure 120 stands proud of the wall batten 116, such that the round end of the support 123 overhands the tiles or slates laid securely above the rafters 112. Consequently when the ventilation i:\intprop\patents\p706999b - 5.3.98 7 cover 122 and apron flashing material 124 are in place, rain water running down the apron flashing cannot enter the roof cavity. In situations where f luted or curved tiles/slates have been employed, tile f illers 130, are utilised to block any spaces between the cover 122 and the tiles/slates in order to prevent the entry of insects or birds into the roof space.

Therefore, air enters the roof space under the eaves, (not shown) passes along beside the raf ters 112 and in between the battens 118 attached to the wall 116. ' Windows ' or holes 121 are f ormed along the length of the ventilation support structure 120 permitting air flow from behind support 120 out underneath the ventilation cover 122 and through tile fillers 130. The tile fillers have a grid opening 131 to permit this flow.

In figure 2, the rows of rafters 112 supporting tiles 126 can be seen. Wall battens 118 attached to supporting wall 116 secure the lengths of ventilation support structure 120 in place.

The ventilation support structures 120 is provided in lengths of f or example 2 to 3 metres and spans the full length of the roof structure. Extruded from for example PVC, the ventilation support structure 120 has a series of the holes or "windows" 121 along the length through which the air passes.

i:\intprop\patents\p706999b - 5.3.98 8 The ventilation cover 122 clips securely over the rounded portion 123 of the support 120, the ventilation cover spanning the full length of the support.

Arrows show the direction of possible air flow from the roof eaves (now shown) in between the rafters, behind the wall battens 118, through the windows in the top of the ventilation support structure 120 and out underneath the ventilation cover 122 and along the tiles. Moreover, grid opening 131 in the f illers 130 is more clearly visible in figure 2.

Figure 3 shows an alternative arrangement of the ventilation system 100 for use in the construction of a flat roof. The arrangement is very similar to that employed in a lean-to roof ventilation system. The ventilation support structure 120 is likewise secured to the supporting wall 116 at a series of points along the wall determined by the positions of the wall battens 118.

In this embodiment however, the wall battens 118 and the ventilation support structure 120 are secured to the wall 116 by a common fastening means 150, for example a bolt which passes through the support structure, through the batten and into the supporting wall 116.

The ventilation cover 122, again has a curved portion 125, an upper portion 140, which extends towards i:\intprop\patents\p706999b - 5.3.98 9 the supporting wall 116 and a lower portion 142, forming a dependant skirt extending towards the roof. The curved portion 125 clips onto the rounded portion 123 of the ventilation support structure 120. Windows 122 are positioned in the top of the ventilation support structure 122 allowing air to circulate.

In the flat roof arrangement a roofing board 136 is supported on the horizontal or near horizontal rafters 112, again with a gap 117 beneath wall battens 118. There is also included atop the rafters, a timber fillet 132 which lies against the support 120 and provides support for roofing felt 127. The felt covers the board 136 and rafters 122 and abuts the ventilation support system 120.

Apron flashing 124, coversthe ventilation cover 122, stretching from the wall where it is secured, down over the cover towards the roof felt 127. A possible variation to the invention is to form windows or holes 1211 in stem 152 of the clip part 125 of the roof cover 122, enabling the section in which holes 121 are formed to be shortened. This enables the whole arrangement to lie closer against the wall 116. Airflow is otherwise the same as described with reference to Figure 1.

A final embodiment of the present invention is described in Figure 4, which can be applied in different i:\intprop\patents\p706999b - 5.3.98 forms to either a flat roof or a lean-to roof, but which is here depicted for a flat roof.

Here, the ventilation support structure 120' and cover 122' embodiment are however formed from a single unit 160, again with the apron flashing 124 passing over the exterior of the cover 122' down towards the roofing felt 127.

1 Windows 121, positioned in the top of the combined ventilation support and cover unit 160, allow air to flow freely around the ventilation system and out over the tiles.

In all of the various embodiments of the invention described above, the arrangement would be constructed to conform to British Standards and provide an airflow passage equivalent to a continuous 25mm gap along the length of the roof behind the wall battens, through the windows of the ventilation support structure and leaving the roof cavity over the tiles or slates.

It can be seen that the main advantages to this type of roof ventilation system include the ease of construction and the reduction in the number of component parts.

i:\intprop\patents\p706999b - 5.3.98 11 One advantage of the system described with reference to Figures 1 and 2 is its ease of assembly. Whether the ventilation system 100 is f ixed with respect to a f lat roof or sloping roof, top part 140 of the cover is arranged to lie against wall 116 so that complete support for the apron flashing 124 is provided. However, this may appear to leave variable gaps between skirt portion 142 of the cover and the roof felt or tiles, as the case may be. However, this is easily accommodated by appropriate raising or lowering of the system 100 before it is fixed to the battens 118 or wall 116, depending on which embodiment is employed.

The advantage of the embodiment of Figure 4, 15 however, is that, because there is no separation between the cover 122' and support 120 ', the thickness of the arrangement can be reduced. Fixing, however, is then the problem, which may be cured by holes 152 in lower part 142 of the cover 1221 to give access to fixing tools (not shown) to the support 1201.

i:\intprop\patents\p706999b - 5.3.98 12

Claims

A roof ventilation system (100) for a roof abutting a wall (116) and having a roof space the system comprising a ventilator adapted to be fixed to the wall above the roof to define an air gap (117) between the wall and ventilator, the ventilator comprising a support structure (120) for fixing to the wall and a cover (122) extending from the support structure and adapted to support the flashing (124), windows (121) formed in the support structure to permit the passage of air from the roof space, through the ventilator and out between the roof and the flashing.
A ventilation system according to claim 1 wherein the cover comprises (122) an upper portion (140) which extends towards the wall, and a lower portion (142) forming a dependant skirt extending towards the roof.
3.

A ventilation system according to claim 1 or 2, wherein the support structure and cover are integrally formed from a continuous extrusion.
4. A ventilation system as claimed in claim 3 in which holes are formed in the dependant skirt permitting i:\intprop\patents\p706999b - 5.3.98 13 access of fixing tools for fixing the support structure to the wall.
5. A ventilation system as claimed in claim 3 or 4, in which a stem element extends substantially perpendicularly from said support structure and from which said cover extends.
6. A ventilation cover as claimed in claim 5, in which said stem connects with said cover intermediate said upper and lower portions.
A ventilation cover as claimed in claim 5 or 6 in which said windows are in the stem element.
8. A ventilation system as claimed in claim 1 or 2, in which said support structure and cover are realisably interconnected.
9. A ventilation system as claimed in claim 8, in which one of said support structure and cover has a round section element and the other of said support structure and cover has a clip section element adapted to clip on to said round section element.
10. A ventilation system as claimed in claim 8, in which said clip is on a clip stem element, said windows being disposed in said clip stem element.

i:\intprop\patents\p706999b - 5.3.98 14
11. A ventilation system as claimed in claim 9 or 10 in which said round section element is on the support structure, as stem element extending substantially perpendicularly from said support structure and having said round section element disposed in an end thereof remote from the support structure, said windows being disposed in the clip element.
12. A ventilation system according to any preceding claim, in which said air gap is provided by battens spaced along the support structure.
13. A ventilator for use in a ventilation system according to any preceding claim.
14. A roof system comprising a sloping roof abutting a wall and tiles on said roof, wherein a roof ventilation system according to any of claims 1 to 12 is provided, the cover overhanging tiles adjacent the wall, an air gap formed between said tiles and the wall.
15. A roof ventilation system as claimed in claim 14, further comprising filler elements adapted to the 25 slope of said tiles to f ill any gap between said covers and tiles to prevent ingress of vermin while permitting flow of air therethrough.

i:\intprop\patents\p706999b - 5.3.98
16. A roof ventilation system comprising a f lat roof abutting a wall and roofing felt on aid roof, wherein a roof ventilator system according to any of claims 1 to 12 is provided, the roofing felt extending between the support structure and cover.
17. A roof system, roof ventilation system and a ventilator for a roof, substantially as hereinbefore described with reference to the accompanying 10 drawings.

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