U.S. patent application number 15/106482 was filed with the patent office on 2016-11-17 for drainage panel.
The applicant listed for this patent is FORTICRETE LIMITED. Invention is credited to Phillip Mark King.
Application Number | 20160333586 15/106482 |
Document ID | / |
Family ID | 50071261 |
Filed Date | 2016-11-17 |
United States Patent
Application |
20160333586 |
Kind Code |
A1 |
King; Phillip Mark |
November 17, 2016 |
DRAINAGE PANEL
Abstract
A drainage panel for arrangement between rafters and battens of
a pitched roof to drain a flow of precipitation from the pitched
roof. The drainage panel has a plurality of flow deflectors capable
of splitting a single flow of precipitation into a plurality as it
flows.
Inventors: |
King; Phillip Mark;
(Witney,Oxfordshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FORTICRETE LIMITED |
Leighton Buzzard Bedfordshire |
|
GB |
|
|
Family ID: |
50071261 |
Appl. No.: |
15/106482 |
Filed: |
December 17, 2014 |
PCT Filed: |
December 17, 2014 |
PCT NO: |
PCT/GB2014/053740 |
371 Date: |
June 20, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04D 2013/049 20130101;
E04D 2013/0486 20130101; E04D 13/0481 20130101; E04D 13/031
20130101; E04D 13/04 20130101 |
International
Class: |
E04D 13/04 20060101
E04D013/04; E04D 13/03 20060101 E04D013/03 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2013 |
GB |
1322726.9 |
Claims
1. A drainage panel for arrangement between rafters and battens of
a pitched roof to drain a flow of precipitation from the pitched
roof, the drainage panel having a plurality of flow deflectors
capable of splitting a single flow of precipitation into a
plurality of flows.
2. The drainage panel of claim 1, including an aperture for
accommodating a roof component, such as a rooflight.
3. The drainage panel of claim 2, wherein one or more flow
deflectors are arranged below the aperture.
4. The drainage panel of claim 1, wherein one or more flow
deflectors are ridges that project from an upper surface of the
drainage panel.
5. The drainage panel of claim 1, wherein the drainage panel has
one or more flow-splitting arrangements constituted by a group of
flow deflectors.
6. The drainage panel of claim 5, wherein the or each
flow-splitting arrangement includes a first deflector that is
configured to deflect an incoming flow of precipitation
inwardly.
7. The drainage panel of claim 6, wherein the first deflector
projects from a longitudinal ridge that extends generally in a
ridge-to-eave direction.
8. The drainage panel of claim 7, wherein the first deflector lies
at an obtuse angle to the longitudinal ridge.
9. The drainage panel of claim 8, wherein a junction between the
first deflector and the longitudinal ridge is curved.
10. The drainage panel of claim 7, wherein the drainage panel
comprises a side deflector that protrudes from the longitudinal
ridge above the first deflector and that is configured to deflect
an incoming flow of precipitation inwardly.
11. The drainage panel of claim 10, wherein the side deflector has
a ridge-facing surface that lies at an obtuse angle to the
longitudinal ridge.
12. The drainage panel of claim 5, wherein the or each
flow-splitting arrangement further includes a second deflector that
is configured to prevent continued inward flow of the incoming flow
of precipitation.
13. The drainage panel of claim 12, wherein the second deflector is
a ridge that lies substantially parallel to the ridge-to-eave
direction.
14. The drainage panel of claim 5, wherein the or each
flow-splitting arrangement further includes a third deflector that
is configured to split the incoming flow into two outgoing
flows.
15. The drainage panel of claim 14, wherein the third deflector is
a ridge that lies generally perpendicular to the ridge-to-eave
direction.
16. The drainage panel of claim 5, wherein the drainage panel
comprises a primary flow-splitting arrangement for dividing an
incoming primary flow into two outgoing secondary flows, and at
least one secondary flow-splitting arrangement arranged below the
primary flow-splitting arrangement in a ridge-to-eave direction for
dividing an incoming secondary flow into two outgoing tertiary
flows.
17. The drainage panel of claim 5, further comprising at least one
flow path divider arranged below the or each flow-splitting
arrangement to define a plurality of flow paths that receive
outgoing flows from the or each flow-splitting arrangement.
18. The drainage panel of claim 17, wherein the or each flow path
divider is a longitudinally-extending ridge.
19. (canceled)
20. (canceled)
21. The drainage panel of claim 1, wherein the drainage panel
comprises a sheet made of a flexible material, such that when the
drainage panel is incorporated into a pitched roof it is distorted
to form channels between the battens and crests over the
battens.
22. The drainage panel of claim 21, wherein one or more deflectors
is configured to deflect a flow of precipitation out of a channel
and towards a crest, such that the precipitation is deflected
uphill.
23. The drainage panel of claim 1, wherein the drainage panel has
one or more batten spacers on its upper surface for spacing battens
above the upper surface of the drainage panel.
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. The drainage panel of claim 1, wherein the drainage panel has a
plurality of panel sections.
29. (canceled)
Description
FIELD OF THE INVENTION
[0001] This invention relates to a drainage panel for a pitched
roof, and in particular to a drainage panel for a pitched roof that
includes a roof aperture accommodating a roof component such as a
rooflight.
BACKGROUND TO THE INVENTION
[0002] The primary function of a roof is to protect a lower space
below the roof from external elements such as wind, snow and
precipitation. A typical pitched roof includes a plurality of
parallel load-bearing rafters that slope from a ridge at the top of
the roof to an eave at a lowermost edge of the roof, and a
plurality of parallel battens disposed on top of, and extending
orthogonally with respect to, the rafters. A pitch angle of the
roof is defined between the rafters and a horizontal plane that
includes the eave.
[0003] Roof covering elements constituted by tiles are affixed
along the battens in horizontally-extending rows or courses. Each
course of tiles underlaps the course of tiles directly above and
overlaps the course of tiles directly below, such that the tiles
overlap in a ridge-to-eave direction. The tiles of the roof act as
a primary drainage system. Precipitation that falls on the roof
flows down the tiles towards the eave and into a gutter arranged
beneath and parallel to the eave. The gutter then carries the
precipitation away from the roof.
[0004] The tiles typically incorporate certain design features to
prevent precipitation penetrating between the tiles. For example,
within a course of tiles, the left-to-right neighbouring tiles may
be arranged to interlock with one another to guard against water
penetration between neighbouring tiles of a course. Between the
courses, upper and lower neighbouring tiles may be provided with
weather checks that guard against ingress of upwardly wind-driven
rain or snow. For example, the weather checks may be ridges
disposed on the undersurface of a tile, that, in a tiled roof, rest
on the upper surface of a tile in the course below. The weather
checks guard against ingress of precipitation by increasing the
tortuosity of the upward path of precipitation. This is
particularly important in low-pitched roofs, which term is
understood in the art to mean roofs having a pitch between
approximately 10.degree. and approximately 15.degree..
[0005] Roofs often include additional roof components that are
accommodated on or in, or that extend through, the roof. For
example, components such as windows (known in the art as
rooflights), vents, GRP dormers, sun pipes, fire escapes or false
chimneys may be incorporated into the roof. Such roof components
require an aperture in the tiles of the roof, to allow light, air
or the roof component to pass through the tiles.
[0006] When such components are incorporated into roofs, it is
important that measures are taken to guard against precipitation
leaking into the space beneath the roof via gaps between the roof
component and the surrounding tiles. In particular, precipitation
running off the roof component is prone to leak between the roof
component and the course of tiles that extends directly below the
roof component (referred to hereafter as the lower bordering
course).
[0007] It is known, therefore, to provide flashing that supplements
the primary drainage system of the tiles to resist penetration of
precipitation. For example, the aperture may be encircled by a
frame that is surrounded by independent flashings that extends from
the frame a short distance up, down and across the roof to surround
the frame. Above and to the sides of the aperture, the flashing
lies above the battens and below the tiles. Beneath the aperture, a
lower portion of the flashing extends downwardly and is raised over
an uppermost edge of the lower bordering course, such that the
flashing is brought onto an upper surface of the tiles of that
course. The lower portion of the flashing therefore incorporates a
distinct upward step that brings the lower portion from a position
below the tiles to a position above the tiles.
[0008] In use, the flashing catches precipitation that falls
between the aperture and the surrounding tiles. That precipitation
flows downwardly from the area surrounding the aperture onto the
lower portion of the flashing. As the precipitation flows down the
lower portion, it is guided over the step at the uppermost edge of
the lower bordering course, and hence is guided onto the upper
surface of the tiles of that course. The precipitation then flows
down the upper surface of those and subsequent lower tiles in the
usual way.
[0009] There are significant disadvantages associated with such
known flashing systems, which limit their effectiveness in
preventing leakage of precipitation, especially in low-pitched
roofs.
[0010] Firstly, to raise the lower portion of the flashing over the
lower bordering course, the lower portion must be brought between
the tiles of the lower bordering course, and the overlapping tiles
of the course above. In this way, the flashing lifts the upper
course of tiles away from the tiles of the lower bordering course,
firstly creating an undesirable gap between the courses and
secondly disrupting contact between the weather check of the upper
tile and the surface of the lower tile. The gap and the disruption
to the weather checks allow ingress of upwardly wind-driven rain
between the courses, resulting in leakage.
[0011] Secondly, at the sides of the aperture the flashing disrupts
the tiles of the roof. The flashing covers the battens, so that the
tiles cannot be fixed to the battens in the vicinity of the
aperture; however, in the interest of preventing leakage, the tiles
must lie as close as possible to the aperture. These conflicting
requirements mean that tiles must be cut precisely to size so as to
be fixed in place around the aperture, and there is little room for
error. An improper job in cutting and laying the tiles, for example
by a rushed or negligent tiler, frequently leads to problematic
leakage around the aperture. Furthermore, if the tiles are profiled
(i.e. having an undulating surface) the tiles may need to be cut at
different points across the tiles width to the side of the
rooflight on the profile, leaving gaps of varying depth beneath the
tiles, further hindering fixing and sealing of the tiles.
[0012] Such flashings are still more problematic when used in
low-pitched roofs. Where the flashing steps upwardly over the
uppermost edge of the lower bordering course, a horizontal trough
is defined in the flashing. Precipitation and debris can collect in
the trough, preventing effective drainage. This problem can be
mitigated to some extent by chamfering the surface of the tile at
the top edge immediately below the rooflight to reduce the height
of the tile profile and reduce the flashing step height over the
tile face. However, this process is time consuming and detrimental
to the function of the tile because it effectively reduces the
protective length of the cover flashing above the tiles, and it
does not, in any case, avoid the problem altogether.
[0013] The applicant's earlier patent application number
GB1221030.8 describes a drainage panel for use in a roof having a
roof aperture that accommodates, for example, a rooflight. The
drainage panel surrounds the roof aperture, and is disposed between
the rafters and the battens of the roof. Below the roof aperture,
the drainage panel extends downwardly from the roof aperture to the
eave of the roof, where it overhangs the gutter. In this way,
precipitation that runs off the rooflight, or that falls between
the rooflight and surrounding tiles, is caught by the drainage
panel and directed down the drainage panel to the eave of the roof,
where it runs into the gutter.
[0014] The drainage panel described in patent application number
GB1221030.8 is an effective means of avoiding leakage around a roof
aperture. However, the inventors have found that during heavier
rainfall, the precipitation falling onto the drainage panel from
above the rooflight tends to flow around rooflight to the left or
right side of the panel. At each of the left and right sides, the
precipitation tends to form a single stream that flows down the
respective side of the panel at high and increasing speed and
overshoots the gutter at the eaves of the roof, resulting in
precipitation running down the walls of the building, or over
spilling the gutter onto the ground below which is also
undesirable.
[0015] Furthermore, although the drainage panel described in
GB1221030.8 causes less disruption to the tiles surrounding the
roof light than the flashing systems described above, the drainage
panel raises the battens of the roof away from the rafters by a
small distance, which can cause low-level disruption to the roof
tiles. It would be desirable to avoid or reduce such
disruption.
[0016] Against this background, it is an object of the invention to
overcome or mitigate one or more of the problems described
above.
STATEMENTS OF THE INVENTION
[0017] The invention resides in a drainage panel for arrangement
between rafters and battens of a pitched roof to drain a flow of
precipitation from the pitched roof, the drainage panel having a
plurality of flow deflectors capable of splitting a single flow of
precipitation into a plurality of flows.
[0018] In this way, the invention provides a drainage panel that,
in use, drains a flow of precipitation from the pitched roof, and
spits the flow of precipitation into a plurality of flows by means
of the deflectors. Each of the plurality of flows is of a smaller
volume than single flow that would drain down the drainage panel in
the absence of the deflectors. Thus the plurality of flows have a
lower momentum than the single flow, and therefore run down the
drainage panel at a lower speed. In this way, the plurality of
flows emerge from the drainage panel at a relatively low speed and
do not overshoot the gutter, but instead flow directly into the
gutter without spillage, to be safely carried away from the roof.
The risk of water draining down the walls of the building as a
result of overshooting the gutter is therefore negligible, and thus
water damage to the building is substantially avoided.
[0019] The drainage panel may include an aperture for accommodating
a roof component, such as a rooflight, so that the drainage panel
may be incorporated into a roof to drain precipitation away from
the roof component accommodated in the aperture.
[0020] In this case, one or more flow deflectors may be arranged
below the aperture. Arranging one or more flow deflectors below the
aperture is particularly advantageous, as it allows a flow of
precipitation below the aperture to be split into a plurality of
flows in preparation for the gutter below.
[0021] For ease of manufacture, one or more of the flow deflectors
may be ridges that project from an upper surface of the drainage
panel.
[0022] The drainage panel may have one or more flow-splitting
arrangements constituted by a group of flow deflectors.
[0023] The or each flow-splitting arrangement may include a first
deflector that is configured to deflect an incoming flow of
precipitation inwardly. The first deflector may project from a
longitudinal ridge that extends generally in a ridge-to-eave
direction.
[0024] The first deflector may lie at an obtuse angle to the
longitudinal ridge, such that a flow of precipitation is guided
downwardly and inwardly by the first deflector.
[0025] A junction between the first deflector and the longitudinal
ridge may be curved, to guide a flow of precipitation gently onto
the first deflector so as to guard against the flow of
precipitation skipping over the first deflector.
[0026] The drainage panel may comprise a side deflector that
protrudes from the longitudinal ridge above the first deflector and
that is configured to deflect an incoming flow of precipitation
inwardly. In this way, the side deflector may guide the incoming
flow of precipitation to take a desired path in preparation for the
first director below.
[0027] The side deflector may have a ridge-facing surface that lies
at an obtuse angle to the longitudinal ridge.
[0028] The or each flow-splitting arrangement may further include a
second deflector that is configured to prevent continued inward
flow of the incoming flow of precipitation. The second deflector
may be a ridge that lies substantially parallel to the
ridge-to-eave direction.
[0029] The or each flow-splitting arrangement may further include a
third deflector that is configured to split the incoming flow into
two outgoing flows. The third deflector may be a ridge that lies
generally perpendicular to the ridge-to-eave direction.
[0030] The drainage panel may comprise a primary flow-splitting
arrangement for dividing an incoming primary flow into two outgoing
secondary flows, and at least one secondary flow-splitting
arrangement arranged below the primary flow-splitting arrangement
in a ridge-to-eave direction for dividing an incoming secondary
flow into two outgoing tertiary flows. In this way, the flow of
precipitation can be divided up into a plurality of flows multiple
times, so that the resulting plurality of flows have an even
smaller volume, and hence flow at an even slower speed.
[0031] The drainage panel may further comprise at least one flow
path divider arranged below the or each flow-splitting arrangement
to define a plurality of flow paths that receive outgoing flows
from the or each flow-splitting arrangement. In this way, each
outgoing flow can be retained in a separate flow path, so that the
outgoing flows cannot recombine after they have been split out from
the incoming flow.
[0032] The or each flow path divider may be a
longitudinally-extending ridge. The or each flow path divider may
extend longitudinally in non-linear fashion, for example in a
zig-zag or sinusoidal fashion, so as to force the flow of
precipitation to meander as it flows down the drainage panel,
thereby slowing the flow of precipitation further. The non-linear
ridges also lend strength to the drainage panel.
[0033] The or each longitudinally-extending ridge may be hollow to
define a channel in an undersurface of the drainage panel. In this
way, any moisture that collects beneath the panel (for example,
moisture penetrating upwardly from the space below the roof) can
escape by running downwardly between the via the channels 74 on the
underside of the or each longitudinally-extending ridge.
[0034] The drainage panel may include a sheet made of a flexible
material, such that when the drainage panel is incorporated into a
pitched roof it is distorted to form channels between the battens
and crests over the battens. To increase flexibility of the sheet,
the sheet may be thin, for example thinner than 3 mm. By making
that sheet out of a flexible plastics material, forces exerted on
the drainage panel by rafters and battens of the roof can be
accommodated by deflection of the drainage panel, rather than by
deflection of the battens. Thus, disruption to the battens can be
reduced, which in turn reduces disruption to the tiles in the
finished roof.
[0035] In such embodiments, one or more deflectors may be
configured to deflect a flow of precipitation out of a channel and
towards a crest, such that the precipitation is deflected uphill.
In this way, the deflectors can be configured to counteract a
tendency of a flow of precipitation to flow down the drainage panel
in the channels.
[0036] The drainage panel may have one or more batten spacers on
its upper surface for spacing battens above the upper surface of
the drainage panel. The batten spacers help to ensure that there is
sufficient space between the drainage panel and the battens for
precipitation, and any debris washed down the panel by the
precipitation, to flow down the panel beneath the battens.
[0037] The drainage panel may comprise a sheet having suspension
ridges configured to sit over rafters of a roof and channels
disposed between the suspension ridges. In this way, the sheet can
dip down between the battens to form the channels, and the channels
extend between the rafters, below the level of the battens, so that
disruption to the battens is minimised still further.
[0038] The channels may be of generally rectangular cross section
perpendicular to a ridge-to-eave direction, so that the sides of
the channels can sit flush against the neighbouring rafters. Each
channel may have deflectors that are configured to split a single
flow of precipitation in the channel into a plurality of flows.
[0039] An upper surface of the drainage panel may be textured so as
to reduce the surface tension of liquid running down the drainage
panel. Reducing the surface tension of liquid running down the
drainage panel in this way slows the flow of liquid, and also helps
to prevent the flow of liquid following the trail of a previous
flow as it runs down the drainage panel.
[0040] The drainage panel may have a plurality of panel sections.
For example, the drainage panel may have upper and lower panel
sections that are separate pieces. Alternatively, the drainage
panel may be formed from a single piece.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] In order that the invention might be more readily
understood, reference will now be made, by way of example only, to
the following drawings, in which:
[0042] FIG. 1 is a perspective view of a tiled pitched roof
incorporating a drainage panel according to an embodiment of the
invention;
[0043] FIG. 2 is a perspective view of the roof of FIG. 1 with its
tiles removed;
[0044] FIG. 3 is a perspective view of the drainage panel of FIGS.
1 and 2, viewed in an eave-to-ridge direction;
[0045] FIG. 4 is a perspective view of the drainage panel of FIG.
3, viewed in an eave-to-ridge direction, and incorporated into a
roof such that battens extend across the drainage panel;
[0046] FIG. 5 is a partial cross-sectional view of the roof of FIG.
1 incorporating a drainage panel, taken along the line A-A of FIG.
2;
[0047] FIG. 6 is a partial detailed view of the drainage panel of
FIG. 3, viewed in an eave-to-ridge direction, showing the
arrangement of deflectors on the drainage panel below the aperture
area;
[0048] FIG. 7 is a partial detailed view of an upper portion of the
drainage panel of FIG. 3, viewed in an eave-to-ridge direction,
showing the path of precipitation falling on the drainage panel
above the rooflight.
[0049] FIG. 8 is a partial detailed view of a left flow region
forming a part of the drainage panel of FIG. 4, showing the paths
taken by the flows of precipitation when the drainage panel is in
use during heavy rainfall;
[0050] FIG. 9 is a perspective view of an upper panel section
forming part of the drainage panel of FIG. 3, viewed in an
eave-to-ridge direction;
[0051] FIG. 10 is a perspective view of a lower panel section
forming part of the drainage panel of FIG. 3 viewed in an
eave-to-ridge direction;
[0052] FIG. 11 is a cross-sectional view of the drainage panel of
FIG. 3 along the line B-B;
[0053] FIG. 12 is a cross-sectional view of a roof incorporating a
drainage panel according to another embodiment of the invention;
and
[0054] FIG. 13 is a cross-sectional view of a flashing in use in
sealing between a rooflight and the drainage panel of FIG. 3.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0055] FIG. 1 illustrates a pitched roof 10 having a plurality of
tiles 12 exemplifying roof covering elements, which may
alternatively be, for example, slates. The tiles 12 extend from an
upper edge 14 of the roof, described here as a ridge, but which may
alternatively be a top abutment, to an eave 16 at a lower edge of
the roof 10.
[0056] A roof aperture 18 is provided in the roof 10, so as to
define an opening extending through the roof 10. The roof aperture
18 is surrounded by a frame (not shown), and accommodates a roof
component (not shown), which, in the embodiments described below,
is exemplified as a rooflight.
[0057] FIG. 2 illustrates the structure of the roof 10 that lies
beneath the tiles 12. It will be apparent that the roof 10 also
includes a plurality of parallel rafters 20 that extend down the
roof 10 to the eave 16, and a plurality of parallel tile battens 22
extending above and orthogonally with respect to the rafters 20. A
roof underlay such as a breather membrane (not shown) extends
across the roof 10 and is provided between the rafters 20 and the
battens 22. A fascia board 24 extends along the eave 16.
[0058] A drainage panel 26 is laid over the top of the draped
underlay and disposed between the rafters 20 and the battens 22.
The drainage panel 26 encircles the roof aperture 18, and from the
roof aperture 18 down to the eave 16.
[0059] The rooflight is supported and held in alignment with the
roof aperture 18 by the rafters 20 that neighbour the roof aperture
18. The rooflight is attached to the rafters 20 by suitable
fixings, such as brackets, which also serve to transfer the load of
the rooflight to the rafters 20.
[0060] The drainage panel 26 extends outwardly from the roof
aperture 18 up, down and across the roof 10 to surround the roof
aperture 18. In all directions, the drainage panel 26 is disposed
between the rafters 20 and the battens 22, such that the drainage
panel 26 extends under the roof tiles 12. Said another way, an
upper face 28 of the drainage panel 26 faces the battens 22 and a
lower face of the drainage panel (not shown), faces the rafters 20.
Below and to the sides of the aperture 18, the drainage panel 26 is
disposed above the underlay. Above the aperture 18, a portion of
the underlay overlaps the drainage panel 26.
[0061] Above and to the sides of the roof aperture 18, the drainage
panel 26 extends a short distance away from the aperture 18. Below
the roof aperture 18, the drainage panel 26 extends continuously
from the roof aperture 18 to the eave 16.
[0062] The drainage panel 26 is supported in the roof 10 by
supplementary rafters 32, which are disposed at, and aligned with,
respective side edges 34 of the drainage panel 26. Inner sides 33
of the supplementary rafters 32 are spaced apart by a distance that
is slightly less than the width of the drainage panel 26. In this
way, the side edges 34 of the drainage panel 26 can be supported
by, and fixed to, respective supplementary rafters 32. The spacing
between outer sides 35 of the supplementary rafters 32 is greater
than the width of the drainage panel 26, such that part of an upper
surface 36 of the rafters 20 remains uncovered by the drainage
panel 26, for attachment of the battens 22.
[0063] At the eave 16, a lower end portion 38 of the drainage panel
26 extends a short distance beyond the fascia board 24 and may be
disposed above or below the upper edge 40 of the fascia board 24.
If the drainage panel 26 is disposed below the upper edge 40 of the
fascia board 24, the upper edge 40 is provided with a recess 42
aligned with the drainage panel 26 which allows the fascia board 24
to receive the lower end portion 38. A gutter (not shown) is
provided beneath the lower end portion 38 to receive precipitation
from the tiles 12 and the drainage panel 26.
[0064] Referring now to FIG. 3, which shows the drainage panel 26
in isolation for convenience, in the embodiment illustrated, the
drainage panel 26 is formed from upper and lower panel sections
26a, 26b. The drainage panel 26 includes a base in the form of a
substantially flat, rectangular sheet 49. The sheet 49 is flexible,
but of self-supporting stiffness, such that it maintains its
substantially flat configuration without external support. The
upper face 28 of the sheet 49 is textured. The texture of the upper
face breaks the surface tension of any liquid running down the
drainage panel 26, thereby reducing the speed at which the liquid
flows, and reducing the tendency for flows of precipitation to
follow the trail of previous flows.
[0065] A rectangular panel aperture 50 is provided in the sheet 49.
The panel aperture 50 is offset in the ridge-to-eave direction,
such that the panel aperture 50 is closer to an upper end 52 of the
drainage panel 26 than a lower end 38 of the drainage panel 26. As
shown in FIG. 2, the panel aperture 50 is aligned with the roof
aperture 18, and is dimensioned to accommodate the rectangular
rooflight and the frame that surrounds it. Thus, the panel aperture
50 is of slightly larger dimensions than the frame surrounding the
rooflight. Although the panel aperture 50 is disposed in `portrait`
manner it could also be disposed in `landscape` manner.
Alternatively the panel aperture 50 could be any convenient shape
other than rectangular.
[0066] A rectangular frame 54 also surrounds the panel aperture 50.
The frame 54 includes four projecting walls that extend
orthogonally and continuously away from the upper face 28 of the
drainage panel 26. In the assembled roof structure 10, the frame 54
of the drainage panel 26 surrounds and is sealed to the frame
surrounding the rooflight by means of a suitable cover flashing, an
example of which will be explained in detail later. In this way,
the drainage panel 26 sits around, and is held in place, between
the rafters 20 and the battens 22 without the need for fixings that
would otherwise perforate the drainage panel 26, which could leave
the drainage panel 26 prone to leakage, especially if the
perforations are inappropriately placed. Alternatively, the
drainage panel 26 can hang from the frame surrounding the
rooflight.
[0067] At the sides of the drainage panel 26, parallel ridges 46
project from the upper face 28 of the drainage panel 26. A central
ridge 46a, parallel to the side ridges 46, also extends down the
centre of the drainage panel 26, below the panel aperture 50. Each
ridge 46 is of constant height above the upper face 28 of the panel
26. However, the ridges 46 differ in height. Specifically, the
heights of the ridges 46 decrease in the outward direction, such
that a ridge 46 closest to the panel aperture 50 is the highest and
a ridge 46 closest to an outer edge 34 of the drainage panel 26 is
the lowest.
[0068] The ridges 46, 46a perform two functions. Firstly the ridges
46, 46a act as platforms that space the battens 22 of the roof
structure 10 apart from the upper face 28 of the drainage panel 26.
Secondly, the ridges 46, 46a define left and right flow regions
26c, 26d of the panel 26, with the left flow region 26c being
defined between the left side ridges 46 and the central ridge 46a,
and the right flow region 26d being defined between the right side
ridges 46 and the central ridge 46a. As precipitation flows down
the panel 26 its flow path is restricted by the ridges 46, 46a to
either the left flow region 26c or the right flow region 26d.
[0069] Below the panel aperture 50, deflectors, generally indicated
at 60, and batten spacers, generally indicated at 70, project from
the upper face 28 of the drainage panel 26. The deflectors 60 and
batten spacers 70 have identical arrangements in the left flow
region 26c and the right flow region 26d.
[0070] The deflectors 60 and batten spacers 70 take the form of
narrow ridges that project orthogonally from the upper surface 28
of the drainage panel 26. The deflectors 60 are generally of the
same height as the central ridge 46, and the tallest of the side
ridges 44 of the drainage panel 26, which in the embodiment
illustrated is approximately 10 mm. The batten spacers 70 are
generally of a height that is less that the height of the
deflectors 60, which in this example is approximately 5 mm.
[0071] When the drainage panel 26 is installed in a roof 10, the
batten spacers 70 act as platforms that space the battens 22 away
from the upper surface 28 of the drainage panel 26, ensuring that
there is space between the drainage panel 26 and the battens 22 for
flowing precipitation.
[0072] When precipitation runs down the panel 26, the deflectors 60
direct the flow of precipitation down the drainage panel 26.
[0073] In particular, and according to the invention, the
deflectors 60 are configured and arranged to split a single flow of
precipitation into a plurality of flows, as will be explained in
more detail later.
[0074] Better to understand the configuration and arrangement of
the deflectors 60 of the drainage panel 26 it is necessary to
understand that when the panel 26 is incorporated into a roof 10,
the panel is distorted by the rafters 20 and the battens 22, as
will now be explained.
[0075] The sheet 49 of the drainage panel 26 is made of a flexible
plastics material, to permit resilient deformation of the sheet 49.
The resilient deformation is also aided by the sheet being thin. In
this example, the drainage panel 26 is made of acrylonitrile
butadiene styrene (ABS) and is approximately 2 mm thick, although
the drainage panel 26 may be made of any suitable material and may
be of any suitable thickness consistent with producing the
requisite degree of flexibility.
[0076] FIG. 4 illustrates the position of the battens 22 across the
drainage panel 26 when the drainage panel 26 is incorporated into
the roof 10 between the rafters 20 and the battens 22. The battens
22 push on the parallel ridges 46, 46a at the sides and the center
of the panel 26 to exert a downward force that is generally
perpendicular to the plane of the sheet 49. This is counteracted by
the rafters 20, which exert an opposed upward force on the sheet
49. Because the drainage panel 26 is flexible, the drainage panel
is distorted by these opposed forces.
[0077] FIG. 5 illustrates the deformation of the sheet 49 when it
is incorporated between the rafters 20, 32 and battens 22 of the
roof 10. In the region of the ridges 46, 46a, the downward force
exerted by the battens 22 pushes portions of the drainage panel
downwardly, out of the plane of the sheet 49 and into the roof. The
gradually increasing heights of the ridges 46 moving inwardly means
that the panel is pushed progressively further into the roof as the
battens 22 extend across the drainage panel 26.
[0078] This downward deformation in the vicinity of the ridges 46,
46a forms channels 44 that run longitudinally in the ridge-to-eave
direction. A central channel 44a is formed in the vicinity of the
central ridge 46a, and left and right side channels 44b are formed
in the vicinity of the side ridges 46.
[0079] Between the channels 44, the rafters 20, 32 support the
drainage panel 26 above the position of the channels 44 to form
corresponding crests 43 that also run longitudinally in the
ridge-to-eave direction. In this way, the drainage panel 26 is
distorted into a corrugated configuration, with alternating
longitudinal crests 43 and channels 44.
[0080] The flexibility of the sheet 49 of the drainage panel 26
means that the forces exerted by the battens 22 and the rafters 20
on the drainage panel 26 are accommodated primarily by deformation
of the sheet 49, rather than by deflection of the battens 22. This
is particularly advantageous, as it means that the battens 22 may
extend over the drainage panel 26 substantially without
deformation. This allows the tiles 12 to be fixed to the battens 22
with virtually no disruption to the tile arrangement, and in
particular without disruption to any interlocks between
neighbouring tiles 12.
[0081] However, the deformation of the sheet 49 means that when the
drainage panel is in use in draining precipitation, the
precipitation tends to run towards the lowest points 45 of the
channels 44 that are formed by the deformation of the sheet 49,
such that the channels 44 form easy flow paths for precipitation
running off the panel 26. In the absence of the flow deflectors 60,
precipitation running off the drainage panel 26 would therefore
down each of the channels 44 in a single flow of large volume. The
large volume of water in the single flow results in a large
momentum, and hence the single stream would flow at high speed,
causing the flow to overshoot the guttering at the eave 14 of the
roof 10.
[0082] The deflectors 60 are therefore configured to counteract the
tendency of the precipitation to run into the channels 44 in single
streams. Specifically, the deflectors 60 are configured and
arranged to be capable of splitting a single flow of precipitation
in each of the left and right flow regions 26c, 26d into a
plurality of smaller flows. The deflectors 60 are also arranged to
guide the flows away from the channels 44 where required, and in
particular to guide the flows towards the crests 43 of the left and
right flow regions 26c, 26d. This means that the deflectors 60 must
be configured to guide the flow of precipitation uphill, out of a
channel 44 and towards a crest 43.
[0083] The configuration and arrangement of the deflectors 60 in
the left flow region 26c will now be described in detail, starting
from the panel aperture 50 and moving in the ridge-to-eave
direction (i.e. in the order in which the deflectors 60 would be
encountered by precipitation flowing down the drainage panel 26),
and with reference to FIGS. 6 to 8, which illustrate the deflector
arrangement. On FIGS. 6 and 8 the positions of the base 45 of the
longitudinal channels 44 is indicated for reference by dashed
lines. It should be appreciated that the right flow region 26d,
including the arrangement of the deflectors 60, is a mirror image
of the left flow region 26c, and hence will not be described in
detail for conciseness.
[0084] Referring to FIG. 6, to the left of the panel aperture 50, a
side deflector 62 projects inwardly from the inner most ridge 46.
In the embodiment illustrated the side deflector 62 projects into
the left flow region 26c by approximately 10 mm. The side deflector
62 is shaped generally as a trapezium. A ridge-facing surface of
the side deflector 62 is angled downwardly (i.e. at an obtuse angle
to the longitudinal side ridge 44), so as to guide precipitation
inwardly towards a centre of the left flow region 26c. An
eave-facing surface of the side deflector is substantially parallel
to the battens 22 of the roof 10, and an inner side surface that
joins the ridge-facing and eave-facing surfaces is orthogonal to
the eave-facing surface.
[0085] Below the panel aperture 50 is a group of deflectors 60
(FIG. 10) that constitute a primary flow-splitting arrangement 63a.
The primary flow-splitting arrangement 63a includes a first, angled
deflector 64, a second, vertical deflector 66 and a third,
horizontal deflector 68. The angled deflector 64 extends inwardly
and downwardly from the innermost ridge 46, such that the angled
deflector 64 extends across the left channel 44b and towards the
crest 43 at a centre of the left flow region 26c. At the junction
between the angled deflector 64 and the side ridge 46 the
ridge-face surface is curved, with a shallow radius of curvature.
The angled deflector 64 leads towards the vertical deflector 66.
The vertical deflector 66 is arranged inwardly of the crest 43, and
extends downwardly in the ridge-to-eave direction. Below the
vertical deflector 66 is a horizontal deflector 68 that extends
horizontally from the left channel 44b, over the crest 43 and
towards the central channel 44a.
[0086] Moving downwardly from the primary flow-splitting
arrangement 63a, two vertical batten spacers 70 extend downwardly
from the horizontal deflector 68. Beneath the batten spacers 70 and
to the left hand side of the left flow region 26c, a further side
deflector 62 projects inwardly from the inner most ridge. This
further side deflector 62 is of substantially the same formation as
the side deflector 62 described above. Below the further side
deflectors 62 are further batten spacers 70, consisting of a
horizontal batten spacer and two vertical batten spacers.
[0087] Continuing downwardly, beneath the further batten spacers 70
are two secondary flow-splitting arrangements 63b, 63c. Each of the
secondary flow-splitting arrangements 63b, 63c mimics the primary
flow-splitting arrangement 63a, and in the same manner includes an
angled deflector 64b, 64c that extends inwardly towards a vertical
deflector 66b, 66c, and a horizontal deflector 68b, 68c disposed
below the vertical deflector 66b, 66c.
[0088] A left secondary flow-splitting arrangement 63b is disposed
at the left hand side of the left flow region 26c. The angled
deflector 64b of the left secondary flow-splitting arrangement 63b
extends from the innermost ridge 46 of the parallel side ridges 46
towards the crest 43. Conversely, a right secondary flow-splitting
arrangement 63c is disposed at the right hand side of the left flow
region 26c, and the angled deflector 64c of the right secondary
flow-splitting arrangement 63c extends inwardly from the central
ridge 46a towards the crest 43.
[0089] Below the secondary flow-splitting arrangements 63b, 63c are
three elongate ridges 47 (FIG. 3) that extend downwardly to the end
38 of the panel 26 in a zig-zag fashion. The three elongate ridges
47 divide the left flow region 26c into four flow paths 48 that lie
between the side ridges 46 and the central ridge 46a that extend to
the end 38 of the panel 26. In this way, the elongate ridges 47
constitute flow path dividers.
[0090] Referring back to FIG. 1 of the drawings, when the drainage
panel 26 is incorporated into a roof 10, and the roof 10 is
subjected to heavy rainfall, rain is directed down the roof from
the ridge 16 towards the eave 16. When draining precipitation
reaches the rooflight, it will flow off the tiles 12 that lie
directly above the rooflight and will fall between the tiles 12 and
the rooflight, where it will be caught by the drainage panel
26.
[0091] Referring now to FIG. 7, precipitation that is caught by the
drainage panel 26 above the rooflight will flow down either the
left side or the right side of the drainage panel, such that it is
directed either to the left flow region 26c or the right flow
region 26d. In this way, the draining precipitation forms two
primary flows 80: one that flows towards the left flow region 26c
and another that flows towards the right flow region 26d.
[0092] The flow of precipitation in the left flow region 26c will
now be described with reference to FIG. 8. It will be appreciated
that the flow of precipitation in the right flow region 26d is a
mirror image of the flow in the left flow region 26c, and so will
not be described in detail for conciseness.
[0093] As the primary flow 80 enters the left flow region 26c, the
side deflector 62 deflects the flow inwardly away from the side
ridge 46 in preparation for the primary flow-splitting arrangement
63a below. As the primary flow 80 continues down the drainage panel
26, the primary flow 80 begins to flow downhill and back towards
the left hand channel 44a. However, before the primary flow 80 can
reach the lowest point 45 of the channel 44a, the primary flow 80
encounters the primary flow-splitting arrangement 63a.
[0094] The primary flow-splitting arrangement 63a splits the
primary flow 80 into first and second secondary flows 81a, 81b. The
primary flow 80 is firstly deflected inwardly by the angled
deflector 64. The shallow radius of curvature of the angled
deflector 64 means that the primary flow 80 hits the angled
deflector 64 at a shallow angle. This shallow angle guards against
the primary flow 80 skipping over the angled deflector, which would
allow the primary flow 80 to avoid the primary flow-splitting
arrangement 63.
[0095] The angled deflector 64 deflects the primary flow 80
inwardly and out of the left hand channel 44b. In this way, the
angled deflector 64 directs the primary flow 80 uphill, towards the
crest 43 of the left flow region 26c. The primary flow 80 is
prevented from flowing into the central channel 44a by the vertical
deflector 66, which forces the primary flow 80 downwardly to the
horizontal deflector 68. The first vertical deflector 66 is
arranged to direct the primary flow 80 such that the primary flow
80 hits the first horizontal deflector 68 substantially at the
crest 43. In this way, when the primary flow 80 hits the horizontal
director 68 a first portion of the primary flow 80 runs to the
left, towards the left channel 44b, forming a first secondary flow
81a, and a second portion of the primary flow 80 runs to the right,
towards the central channel 44a, forming a second secondary flow
81b, thereby splitting the primary flow 80 into two secondary flows
81a, 81b.
[0096] Following now the path of the first secondary flow 81a at
the left side of the left flow region 26c, as the first secondary
flow 81a flows downwardly it tends to flow back towards the left
channel 44b. As it flows back towards the left channel 44b it
encounters the second side deflector 62, which deflects the first
secondary flow 81a back towards the centre of the left flow region
26c. As the first secondary flow 81a flows continues to head
downwardly from the second side deflector 62, it heads once again
towards the left channel 44b. Once again, before the first
secondary flow 81a reaches the lowest point 45 of the channel 44b
it encounters the secondary flow-splitting arrangement 63b.
[0097] The second flow-splitting arrangement 63b acts in a manner
that is substantially identical to the primary flow-splitting
arrangement 63a to split the first secondary flow 81a into two
tertiary flows 82a, 82b. The angled deflector 64b directs the first
secondary flow 81a inwardly, out of the channel 44b and towards the
vertical deflector 66b. The vertical deflector 66b prevents the
first secondary flow 81a continuing to the central channel 44a and
directs it instead towards the horizontal deflector 68b, where it
is split into the two tertiary flows 82a, 82b.
[0098] Returning now to the second secondary flow 81b at the right
hand side of the left flow region, after the second secondary flow
81b has been split out from the primary flow 80, it tends to flow
towards the central channel 44a, where it continues downwardly
towards the right secondary flow-splitting arrangement 63c. The
right secondary flow-splitting arrangement 63c splits the second
secondary flow 81b into two further tertiary flows 82c, 82d in
substantially the same manner as the primary flow-splitting
arrangement 63a and the left secondary flow-splitting arrangement
63b: the angled deflector 64c directs the second secondary flow 81b
inwardly, out of the channel 44b, the vertical deflector 66c
prevents the second secondary flow 81b continuing to the central
channel 44a and directs it instead towards the horizontal deflector
68c, where it is split into the two tertiary flows 82c, 82d.
[0099] Thus, the secondary flow-splitting arrangements 63b, 63c
split the two secondary flows 81a, 81b into four tertiary flows
82a, 82b, 82c, 82d.
[0100] Beneath the secondary flow-splitting arrangements 63b, 63c,
each of the tertiary flows 82a, 82b, 82c, 82d is fed into one of
the four flow paths 48 defined by the zig-zag ridges 47. The
zig-zag ridges 47 retain each tertiary flow 82a, 82b, 82c, 82d in
its own flow path all the way down to the end of the left flow
region 26c and off the end of the drainage panel 26, into the
gutter at the eave 14 of the roof 10. The zig-zag nature of the
ridges 47, and hence of the flow paths 48 defined between the
ridges 47, forces the tertiary flows 82a, 82b, 82c, 82d to take a
meandering path down the panel 26, thereby slowing the progress of
the tertiary flows 82a, 82b, 82c, 82d down the drainage panel
26.
[0101] Thus, when a single primary flow 80 enters the left flow
region 26c beneath the panel aperture 50, the deflectors 60 split
the primary flow 80 into two secondary flows 81a, 81b, and again
into four tertiary flows 82a, 82b, 82c, 82d that exit the drainage
panel separately. It will be appreciated the right flow region 26d
mirrors the left flow region 26c, such that the deflectors 60 in
the right flow region 26d also splits a primary flow into four
tertiary flows. In this way, a total of eight tertiary flows are
produced by the deflectors 60 of the drainage panel.
[0102] Each of the eight tertiary flows 82a, 82b, 82c, 82d is of a
smaller volume than the primary flows 80 that would run down the
drainage panel in the absence of the deflectors 60. Thus, it has a
lower momentum, and therefore runs down the drainage panel 26 at a
lower speed. The speed of the flows down the drainage panel is also
slowed by the meandering path that is forced upon the flows by the
flow-splitting arrangements, and slowed again by the zig-zag
channels 48.
[0103] Thus, the effect of the deflectors 60 is that when the eight
tertiary flows emerge into the gutter at the eave 14 of the roof
10, they are flowing at a relatively low speed. In this way, the
eight tertiary flows do not overshoot the gutter, but instead flow
directly into the gutter without spillage, to be safely carried
away from the roof 10. The risk of water draining down the walls of
the building as a result of overshooting the gutter is therefore
negligable, and thus water damage to the building is substantially
avoided.
[0104] To manufacture the panel 26, each of the upper and lower
panel sections 26a, 26b is made separately by forming a plastic
sheet. The forming of the plastic sheet(s) is conveniently by
vacuum forming over a single tool. Alternatively, the or each
plastic sheet may be moulded for example, by pressing the plastic
sheet between a pair of complementary mould tools.
[0105] FIGS. 9 and 10 illustrate the upper and lower panel sections
26a, 26b in isolation immediately after being formed. FIG. 10
reveals that the lower panel section 26a initially includes a
deflector-free section 74 below the zig-zag ridges 47. Before the
drainage panel 26 is incorporated into a roof, the lower panel
section 26a is cut to fit the roof, for example by cutting the
lower panel section along the line C-C, thereby removing the
deflector-free section 74, and as much of the remaining panel 26 as
is necessary.
[0106] The mould tools that are used to press the sheet comprise
formations that define the ridges 44, 47, deflectors 60 and batten
spacers 70 during pressing. In this way, and as is illustrated in
FIG. 10, the longitudinal ridges 44, 47, deflectors 60 and batten
spacers 70 are hollow, such that they define corresponding channels
74 on an underside 29 of the panel 26. As is visible in FIG. 11,
the channels formed on the underside of the zig-zag ridges 47
extend to the end of the drainage panel 26, and hence open on to
the end of the drainage panel 38 above the fascia board 24.
[0107] When the panel 26 is in use in the roof 10, any moisture
that collects between the roof underlay layer and the lower surface
29 of the panel 26 (for example, moisture penetrating upwardly from
the space below the roof through the breathable roof underlay) can
escape by running downwardly between the roof underlay layer and
the panel 26 via the channels 74 on the underside of the zig-zag
ridges 47. In this way, the channels 74 provide an escape path for
trapped moisture. Such an escape path would not exist were the
underside 29 of the panel 26 to sit flat against the roof underlay
across the entire panel 26 or over the upper edge of the fascia
board 24 or recess beneath the true fascia board height.
[0108] FIG. 12 illustrates in cross-section a drainage panel 126
according to another embodiment. In this embodiment, rather than
channels and crests being formed in the sheet 49 by deformation of
the drainage panel 26 caused by the forces exerted on the drainage
panel 26 by the battens and the rafters, the cross section of the
drainage panel 126 perpendicular to the ridge-to-eave direction is
shaped such that the panel 126 steps downwardly between the rafters
20, 32 to form rectangular channels 144. In this way, the panel 126
according to this embodiment can be accommodated between the
rafters 20, 32 and the battens 22 with no disruption to the battens
22.
[0109] Considering the cross section in more detail, and moving
inwardly from a left edge of the panel 126, at the left edge of the
panel 126, the sheet 149 of the panel 126 sits flush against the
supplementary rafter 32 to define a raised portion or a wide ridge
143. The raised portion acts as a suspension ridge 143 from which
the panel 126 can be suspended over the rafters 20, 32 when in
use.
[0110] At an edge of the supplementary rafter 32, the sheet 149
steps downwardly by a distinct step of approximately 10 mm to
define a left sidewall 145a of the channel 144. Continuing
inwardly, the sheet 149 extends towards the rafter 20 to define a
base 145 of channel 144. At the rafter 20, the sheet 149 steps
upwardly to define a right side wall 145b of the channel 144. The
sheet 149 lies flush against the rafter 20 to define a further
raised portion 143. The pattern of raised portions 143 across the
rafters 20, 32 and the channels 144 between the rafters 20, 32,
continues across the sheet 149 to the right side of the panel
126.
[0111] When the panel 126 is incorporated into a roof 10, the panel
126 is supported by the rafters 32, 20 at the suspension ridges
143, with the channels 144 hanging below the battens 22. The base
145 of the channel 144 is therefore spaced apart from the battens
22, such that precipitation can flow freely below the battens
22.
[0112] Deflectors, not visible in FIG. 12, project from an upper
surface 128 of the panel 126. As in the previous embodiment, the
deflectors are thin ridges, and are arranged to split a flow of
precipitation into a plurality of flows. In the same manner as the
embodiment described above, the deflectors are configured and
arranged in a flow-splitting arrangement that includes an angled
deflector that deflects a flow away from a side wall 127a, 127b of
the channel 144, a vertical deflector that deflects downwardly, and
a horizontal deflector below the vertical deflector that splits the
flow into two flows. Flow path dividers, such as the zig-zag ridges
described above, are provided below the flow-splitting arrangements
to retain the split flows in separate flow paths to the end of the
drainage panel 26.
[0113] In the embodiment illustrated in FIG. 12, the panel 126
includes a large central channel 144a and smaller side channels
144b. In this embodiment, a flow of precipitation is restricted to
flow within a single channel 144 and so each flow-splitting
arrangement lies within a single channel. For example, deflectors
may be arranged in each of the channels 144a, 144b to split a
single flow in each channel into four flows, thereby resulting in
twelve outgoing flows that emerge from the panel.
[0114] Thus, in the embodiment of FIG. 12, the flow of
precipitation in each channel 144 is split into a plurality of
flows by the deflectors. Each of the plurality of flows has a lower
volume of water, and hence a lower momentum, such that the
plurality of flows move at a lower speed than the speed that would
be reached by a combined single flow in the absence of the
deflectors. The split flows therefore do not overshoot the gutter,
but instead run directly into the gutter to be carried away from
the roof.
[0115] In both of the embodiments described, the speed at which
precipitation runs down the drainage panel is generally sufficient
to wash small pieces of debris, such as leaves and twigs, down the
drainage panel. However, if the roof is located in an area that is
particularly prone to debris, debris may become clogged around the
panel aperture.
[0116] This can be mitigated by arranging an open-cell foam layer
around the frame that surrounds the panel aperture. The open-cell
foam allows liquid and small pieces of debris to pass through the
foam, whilst catching larger pieces of debris. The larger pieces of
debris can then be easily removed from the foam, or the foam can be
easily replaced when required.
[0117] Because the foam is open-celled, the foam can be easily
compressed to accommodate the tiles surrounding the rooflight, so
that the arrangement of the tiles around the rooflight is not
disrupted by the foam.
[0118] As has been mentioned above, in the assembled roof structure
10, the frame 54 of the drainage panel 26 surrounds and is sealed
to the frame surrounding the rooflight by means of a suitable cover
flashing.
[0119] FIG. 13 illustrates a suitable cover flashing 200 in in use
in sealing between a frame 56 that surrounds a rooflight (not
shown) and a frame 54 that surrounds a panel aperture 50 of a
drainage panel 26.
[0120] The frame 56 that surrounds the rooflight has an outer face
55 that lies against the frame 54 of the drainage panel 26 when the
drainage panel 26 is incorporated into a pitched roof. Above the
outer face 55 is a step that extends around the perimeter of the
frame. The step includes a ledge 57 that faces upwardly and a riser
58 that extends upwardly, perpendicular to the ledge 57. The riser
58 joins the ledge 57 to an upper surface 59 of the frame 56.
[0121] The flashing 200 is a two-part flashing that has lower and
upper parts 200a, 200b. The flashing 200 may be made of any
suitable metal or plastics material, and is typically made out of
tin.
[0122] The lower part 200a has includes a lower vertical wall 202
that lies against an outer surface of the frame 54 of the drainage
panel 26, a horizontal wall 204 that extends inwardly from the top
edge of the lower vertical wall 202 to lie against the ridge 57 of
the rooflight frame 56, and an upper vertical wall 206 that extends
upwardly from the inner edge of the horizontal wall 204 to lie
against the riser 58 of the rooflight frame 56. The upper part 200b
has a substantially `L` shaped cross section, and includes a
horizontal wall 208 that lies against the upper surface 59 of the
rooflight frame 56, and a short vertical wall 210 that extends
downwardly from an outer edge of the horizontal wall 208 to lie
against an outer surface of the upper vertical wall 206 of the
lower part 200a of the flashing 200 in a push fit.
[0123] To install the flashing, the drainage panel 26 is first
placed over the rooflight frame 56. The lower part 200a of the
flashing 200 is fitted over the rooflight frame 56 and the frame 54
of the drainage panel 26. The upper part 200b is then fitted with a
push-fit over the upper surface 59 of the rooflight frame 56 and
the upper vertical wall 206 of the lower part 200a, so as to secure
the flashing 200 to the frames 54, 56.
[0124] Although in the embodiments described the drainage panel
includes a panel aperture for accommodating a rooflight, the panel
aperture need not accommodate a roof light but may accommodate
other roofing components, and may be of any suitable size or
shape.
[0125] In other embodiments, the drainage panel need not include a
panel aperture at all, but may instead be a continuous sheet.
[0126] Although it is advantageous for either the sheet to be made
of a flexible material such that channels and crests are formed by
deformation of the sheet, or for the sheet to include suspension
ridges having channels defined between them such that the channels
hang below the battens, this need not necessarily be the case, and
the drainage panel may instead be substantially flat and rigid.
[0127] The drainage panel need not necessarily be formed from two
panel sections. The drainage panel may instead by formed as a
single panel section, or may be formed from more than two panel
sections.
* * * * *