Introduction
[0001] This invention relates to a method of insulating around a cavity tray in a cavity
wall, the cavity wall comprising an inner leaf of blockwork and an outer leaf of brickwork
defining a cavity therebetween, and at least one cavity tray to be secured in position
in the cavity on the outer leaf of brickwork. The present invention further relates
to a method of constructing an insulated cavity wall, and to a cavity tray insulating
member for insulating around a cavity tray.
[0002] Providing insulation around cavity trays in wall insulation is a significant problem.
The cavity trays are required adjacent the junction between a two storey gable wall
and a single story extension roof to help evacuate water that has made its way through
the outer leaf of brickwork into the cavity between the outer leaf of brickwork and
the inner leaf of blockwork. Without the cavity trays, water that had made its way
into the cavity between the outer leaf of brickwork and the inner leaf of blockwork
would gather within the cavity wall and eventually cause damage to the interior of
the building. Therefore, it is necessary to provide the cavity trays to help divert
water from inside the cavity back out to the exterior of the outer leaf of brickwork.
However, due to the fact that the cavity trays project inwardly into the cavity, the
cavity trays interrupt the insulation continuity within the cavity, thereby causing
performance deterioration of the wall insulation at the cavity tray line.
[0003] Heretofore, in order to insulate around the cavity trays, the tradesperson was asked
to carefully cut the insulation around the trays and individually pack insulation
into the spaces between adjacent cavity trays. However, this is very time consuming
and difficult to do accurately on site. As well as being labour intensive and expensive,
this method of insulating around the cavity trays in the cavity wall also delayed
the finishing of the wall, leaving the wall exposed to the elements for longer which
is undesirable.
[0004] As a result of the difficulties encountered and the time required to insulate correctly
around the cavity trays, the cavity is more often than not left without insulation
adjacent the cavity trays. The lack of insulation causes a cold bridge at this point
between the interior of the dwelling and the exterior of the dwelling. This cold bridge
is highly disadvantageous as it reduces the overall U value of the insulation of the
dwelling and furthermore results in condensation forming on the cold internal surface
that is left inadequately insulated. This condensation will gather over time causing
mould growth and causing damage to the building and potentially causing harm to the
occupants.
[0005] It is an object of the present invention to provide a method of insulating around
a cavity tray in a cavity wall that overcomes at least some of the problems with the
known methods. It is a further object of the present invention to provide a method
of constructing an insulated cavity wall and a cavity tray insulating member for use
in the methods that overcome some of the problems with the known methods.
Statements of Invention
[0006] According to the invention there is provided a method of insulating around a cavity
tray in a cavity wall, the cavity wall comprising an inner leaf of blockwork and an
outer leaf of brickwork defining a cavity therebetween, and at least one cavity tray
to be secured in position in the cavity on the outer leaf of brickwork, the method
comprising the steps of:
- (a) placing board insulation in the cavity between the inner leaf of blockwork and
the outer leaf of brickwork up to a level below the intended location of the cavity
tray; characterised in that, the method comprises the additional steps of:
- (b) providing a cavity tray insulating member comprising a substantially C-shaped
channel comprising an elongate trunk and a pair of arms bridged by the trunk and projecting
forwardly therefrom, and placing the C-shaped cavity tray insulating member on top
of the insulation in the cavity with one of the forwardly projecting arms positioned
below the intended location of the cavity tray and the other of the forwardly projecting
arms positioned above the intended location of the cavity tray, with the elongate
trunk positioned adjacent to the inner leaf of blockwork and the free ends of the
arms facing towards the outer leaf of brickwork; and
- (c) placing additional board insulation in the cavity on top of the C-shaped cavity
tray insulation member on the forwardly projecting arm positioned above the intended
location of the cavity tray.
[0007] By having such a method, the amount of cutting and the precision of cutting required
to insulate around the cavity tray is significantly reduced. This will simplify and
speed up the process of insulating around the cavity trays. The tradesperson will
no longer be dissuaded from installing insulation around the cavity tray as it will
be far easier than was heretofore the case. Accordingly, as the walls will be properly
insulated, it will be less common to have thermal bridging issues, thereby preventing
heat loss, condensation and mould growth.
[0008] In one embodiment of the invention there is provided a method comprising the intermediate
step of shaping the cavity tray insulating member from a substantially flat layer
of insulating material into a C-shaped channel. By shaping the cavity tray insulating
member into the C-shaped configuration on site, the cavity tray insulating member
may be transported flat thereby conserving space and cost during transit.
[0009] In one embodiment of the invention there is provided a method comprising the step
of, before placing the additional insulation in the cavity on top of the forwardly
projecting arm of the C-shaped cavity tray that is positioned above the intended location
of the cavity tray, placing a damp proof course (DPC) member on top of that forwardly
projecting arm. In this way, a DPC member can be positioned accurately in an ideal
location relative to the cavity trays to direct any moisture in the cavity back towards
the outer skin of the wall.
[0010] In one embodiment of the invention there is provided a method comprising the step
of placing a Z-shaped DPC member on the forwardly projecting arm, the Z-shaped DPC
having a central portion and a pair of legs protruding outwardly in opposite directions
with respect to each other from the central portion and substantially orthogonally
with respect to the central portion, with one leg of the Z-shaped DPC extending upwardly
along the inner leaf of blockwork, the central portion of the Z-shaped DPC extending
forwardly along the forwardly projecting arm and the other leg of the Z-shaped DPC
extending downwardly in front of the forwardly projecting arm for location between
the arm and the outer layer of brickwork. This is seen as a particularly effective
construction of DPC member to use with the method according to the invention and is
also seen as an effective way of mounting the DPC member onto the cavity tray insulation
member in such a way that the DPC member will direct as much moisture from the cavity
back out through the outer leaf of brickwork.
[0011] In one embodiment of the invention there is provided a method comprising the step
of cutting the cavity tray insulation member in a straight line across the cavity
tray insulation member and at one end of the cavity tray insulation member, at an
angle corresponding to the pitch of a roof so that the lateral side of the cavity
tray insulation member is substantially orthogonal to the ground. By cutting the cavity
tray insulation member at an end in a straight line at an angle corresponding to the
pitch of the roof, the installation of the cavity tray insulation member will be further
simplified.
[0012] In one embodiment of the invention there is provided a method comprising the step
of taping the arm of the cavity tray insulating member positioned below the intended
location of the cavity tray to the insulation in the cavity therebelow. By taping
the arm of the cavity tray insulating member to the block insulation below, better
insulation continuity is achieved, thereby improving the U value of the insulation
installation.
[0013] In one embodiment of the invention there is provided a method comprising the step
of securing the C-shaped cavity tray to the inner leaf of blockwork.
[0014] In one embodiment of the invention there is provided a method of constructing an
insulated cavity wall, the cavity wall comprising an inner leaf of blockwork and an
outer leaf of brickwork defining a cavity therebetween, and at least one cavity tray
secured in position in the cavity on the outer leaf of brickwork, the method comprising
the steps of:
providing an inner leaf of blockwork;
providing insulation board on the inner leaf of blockwork to a level below the intended
level of the cavity tray;
providing an outer leaf of brickwork to a level below the intended level of the cavity
tray;
providing a cavity tray insulating member comprising a substantially C-shaped channel
constructed from an insulating material, the C-shaped channel having an elongate trunk
and a pair of arms bridged by the trunk and projecting forwardly therefrom;
placing the cavity tray insulating member trunk against the inner leaf of blockwork
adjacent the intended position of the cavity tray in the outer leaf of brickwork and
above the existing insulation board on the inner leaf of blockwork, the cavity tray
insulating member being positioned so that one arm is substantially below the intended
level of the cavity tray and the other arm is substantially above the intended level
of the cavity tray;
providing insulation board on the inner leaf of blockwork above the cavity tray insulating
member;
mounting the cavity tray in position on the outer leaf of brickwork so that the cavity
tray extends inwardly into the cavity between the arms of the cavity tray insulating
member; and
providing the remaining courses of bricks in the outer leaf of brickwork.
[0015] By having such a method, an adequately insulated cavity wall can be constructed and
finished in a faster, more efficient manner than was heretofore the case. As the amount
of cutting of insulation is reduced and the complexity of the cutting and the fitting
of the insulation are significantly simplified, the insulation of the cavity wall
will not delay the construction of the remainder of the wall as much as was previously
the case. Accordingly, the structure can be finished and weatherproofed sooner than
was heretofore the case which is advantageous.
[0016] In one embodiment of the invention there is provided a method comprising the additional
intermediate step of, prior to providing insulation board on the inner leaf of blockwork
above the cavity tray insulating member, mounting a damp proof course on the uppermost
arm of the cavity tray insulating member. In this way, a DPC member can be positioned
accurately in an ideal location relative to the cavity trays to direct any moisture
in the cavity back towards the outer skin of the wall.
[0017] In one embodiment of the invention there is provided a method comprising the intermediate
step of shaping the cavity tray insulating member from a substantially flat layer
of insulating material into a C-shaped channel.
[0018] In one embodiment of the invention there is provided a cavity tray insulating member
for insulating around a cavity tray in a wall insulation installation, the cavity
tray insulating member comprising a substantially C-shaped channel constructed from
an insulating material, the C-shaped channel comprising an elongate trunk and a pair
of arms bridged by the trunk and projecting forwardly therefrom from a pair of opposing
longitudinal sides of the elongate trunk, and in which the cavity tray insulating
member is constructed from a unitary sheet of insulating material, the unitary sheet
of insulating material having a pair of substantially parallel V-shaped grooves extending
along its length about which the member may be bent from a substantially flat configuration
into the C-shaped channel configuration.
[0019] This is seen as a particularly suitable construction of cavity tray insulating member.
The cavity tray insulating member is dimensioned to fit around the cavity tray and
provide insulation around the cavity tray. It is not necessary to accurately cut the
cavity tray insulating member so that it will fit between the cavity trays and therefore
the construction of cavity tray insulation member will simplify and speed up the insulation
process. The C-shaped channel configuration will provide good insulation continuity
with the insulation panels above and below the cavity trays thereby maximizing the
performance of the insulation as a whole.
[0020] In one embodiment of the invention there is provided a cavity tray in which the cavity
tray has a backing sheet of flexible material on a face of the body opposite the V-shaped
grooves. By having a backing sheet, the backing sheet will hold the parts of the cavity
tray together and will effectively act as a hinge between the arms and the trunk.
[0021] In one embodiment of the invention there is provided a cavity tray insulating member
in which one of the V-shaped grooves has a groove angle of greater than 90°. By having
a groove angle greater than 90°, the arm of the cavity tray insulating member will
form an acute angle with the trunk. If the cavity tray insulating member is installed
so that this arm is the uppermost arm, this will promote run off of water on the arm
into the cavity trays thereby promoting movement of water in the cavity towards the
outer leaf of brickwork.
[0022] In one embodiment of the invention there is provided a cavity tray in which there
is provided a damp proof course (DPC) member connected to one of the arms and extending
along the length of one of the arms. This is seen as a particularly useful aspect
of the present invention as the cavity tray insulating member will promote egress
of water from the cavity as the DPC will capture water coming down the interior of
the cavity, even if the water should be on the inner leaf of blockwork, and will direct
that water towards the cavity trays from where it will be expelled through the outer
leaf of brickwork.
[0023] In one embodiment of the invention there is provided a cavity tray in which the DPC
member is substantially Z-shaped, the DPC member having a central portion and a pair
of legs protruding outwardly from the central portion in opposite directions with
respect to each other and protruding substantially orthogonally with respect to the
central portion.
Detailed Description of the Invention
[0024] The invention will now be more clearly understood from the following description
of some embodiments thereof given by way of example only with reference to the accompanying
drawings, in which:-
Figure 1 is a perspective view of a part-constructed cavity tray insulating member
for use in the method according to the invention;
Figure 2 is a perspective view of a constructed cavity tray insulating member for
use in the method according to the invention;
Figure 3 is a front view of the cavity tray insulating member shown in Figure 2;
Figure 4 is a top plan view of the cavity tray insulating member shown in Figure 2;
Figure 5 is a front view of the part-constructed cavity tray insulating member shown
in Figure 1;
Figure 6 is a top plan view of the part-constructed cavity tray insulating member
shown in Figure 1;
Figure 7(a) and 7(b) are front views of the cavity tray insulating member after it
has been cut at each of its ends at an angle corresponding to the pitch of a roof;
Figures 8(a) and 8(b) are a front view and a top plan view of an alternative construction
of cavity tray for use in the method according to the invention;
Figure 9 is a side cross-sectional view of the cavity tray insulating member installed
in a wall cavity;
Figures 10(a) to 10(d) illustrates a method of constructing a cavity wall without
insulation around the cavity trays known in the art;
Figures 11(a) to 11(g) illustrates a method of constructing a cavity wall with insulation
around cavity trays known in the art; and
Figures 12(a) to 12(g) illustrate a method of insulating around cavity trays in a
cavity wall according to the invention.
[0025] Referring to Figures 1 to 6 inclusive, there is shown a cavity tray insulating member
for use in the methods according to the invention, indicated generally by the reference
numeral 1, the cavity tray insulating member 1 comprising an elongate, substantially
C-shaped or channel-shaped body 3 constructed from an insulating material, the channel-shaped
body 3 comprising a trunk 5 and a pair of arms 7, 9 bridged by the trunk 5 and projecting
forwardly therefrom.
[0026] Referring specifically to Figure 1, the cavity tray insulating member 1 is constructed
from a single sheet of insulating material, the single sheet of insulating material
having a pair of substantially V-shaped grooves 11, 13 extending along the entire
length of the cavity tray insulating member 1. Preferably, a backing sheet of flexible
material (not shown) is provided on a rear face 15 of the cavity tray insulating member
1. In this way, the cavity tray insulating member can be folded along the V-shaped
grooves 11, 13 into a channel shape and the backing sheet will effectively act as
a hinge. There are several advantages to such a construction. This construction will
enable the cavity tray insulating member to be stored and transported in a flat configuration
as shown in Figure 1 and transformed easily on site into a channel shaped configuration
as shown in Figure 2. Furthermore, this construction will simplify the manufacture
of the cavity tray insulating member 1 as the V-shaped grooves may be simply cut out
of a single unitary piece of insulating material with a saw or other cutting device.
[0027] Referring specifically to Figure 6, there is shown a pair of arrows, A, that indicate
the direction in which the arms 7, 9 are folded inwards about the V-shaped grooves
11, 13 to form the channel-shaped body 3 (as illustrated in Figure 2). In Figure 6,
it can be seen that the V-shaped grooves extend practically the entire way from front
to back across the single sheet of insulating material and form a V-shaped groove
with an angle of approximately 90 degrees. If desired, the angle of the V-shaped groove
for one or both grooves can be more than 90 degrees, for example approximately 100
degrees. By having an angle of approximately 100 degrees, the arm 7, 9 will form an
acute angle of approximately 80 degrees with the trunk 5 and the arm will effectively
be pointing inwardly towards the other arm on a converging path. The angle that the
arm 7, 9 makes with the trunk 5 is indicated by the letter B in Figure 4. If the arm
forms an acute angle with the trunk, this will facilitate water run-off in the desired
direction as will be further understood with reference to the following description
showing the cavity tray insulation member in position in the cavity.
[0028] Referring to Figures 7(a) and 7(b), there are shown a pair of views of a cavity tray
insulation member, similar to those shown in Figures 1 and 2 respectively, in which
the ends 12, 14 of the cavity tray have been cut in a straight line at an angle so
that the ends 12, 14 will be substantially perpendicular to the ground when the cavity
tray insulation member is mounted in the cavity wall installation. This will be understood
further with reference to the following description of the method of installation
of the cavity tray insulation member.
[0029] Referring to Figures 8(a) and 8(b), there is shown an alternative construction of
cavity tray insulation member, indicated generally by the reference numeral 16, in
which like parts have been given the same reference numeral as before. The cavity
tray insulation member 16 further comprises a damp proof course (DPC) member 17 mounted
on one arm 7 thereof. The DPC 17 is substantially Z-shaped and comprises a central
portion 18 and a pair of legs 19, 20 protruding outwardly in opposite directions with
respect to each other from the central portion 18 and substantially orthogonally with
respect to the central portion. One leg 19 of the Z-shaped DPC is arranged to extend
upwardly along the inner leaf of blockwork (not shown) whereas the central portion
18 of the Z-shaped DPC extends forwardly along the forwardly projecting arm 7. The
other leg 20 of the Z-shaped DPC extends downwardly in front of the forwardly projecting
arm 7 for location between the arm and an outer layer of brickwork (not shown). The
DPC 17 is permanently secured to the cavity tray insulation member 16 by an adhesive
however it will be understood that the DPC could be installed on site if desired.
[0030] Referring to Figure 9, there is shown a cross-sectional view of a gable wall 21 with
wall insulation in which the cavity tray insulating member 1 according to the invention
has been installed. The gable wall comprises an inner leaf of blockwork 23, an outer
leaf of brickwork 25 and a plurality of cavity trays 27 inserted between the bricks
28 of the outer leaf of brickwork 25 and extending inwardly into a cavity 29 between
the inner leaf of blockwork 23 and the outer leaf of brickwork 25. The cavity trays
27 comprise a mounting plate 31 that sits intermediate a pair of adjacent bricks 28
and a winged plate 33 that extends inwardly into the cavity to collect water and direct
the water towards the mounting plate 31.
[0031] The function of the cavity tray 27, as is well known in the art, is to collect water
that seeps in through the outer leaf of brickwork 25 above the cavity trays and that
travels down the inner surface 35 of the outer leaf of brickwork 25, and to direct
that water back out through the outer leaf of brickwork 25 onto the roof of the single
story extension (not shown) just below the cavity trays. Without the cavity trays,
the water would travel down to the bottom of the cavity 29 and would gather in the
cavity before seeping in through the inner leaf of blockwork 23 causing damage to
the property.
[0032] The wall insulation comprises a lower insulation board 41 and an upper insulation
board 43 as well as the channel-shaped cavity tray insulating member 1 sandwiched
therebetween. It can be seen that the channel shaped cavity tray insulating member
1 presents a flat surface to both the lower insulation board 41 and the upper insulation
board 43. The wall insulation further comprises a damp proof course (DPC) member 17
which is substantially Zee-shaped and has been fitted to the cavity tray insulating
member once the cavity tray insulating member has been put in position in the cavity.
The DPC member 17 has a first leg 19 that fits behind the upper insulation board 43
between the upper insulation board 43 and the inner leaf of blockwork 23, a central
portion 18 that extends outwardly over the upper arm 7 of the channel-shaped cavity
tray insulating member 1 and a second leg 20 that depends downwardly in front of the
arm 7 of the cavity tray insulating member between the cavity tray insulating member
1 and the outer leaf of brickwork 25. In this way, water will not travel from the
outer brickwork to the inner blockwork and water will be directed into the cavity
trays 27 and from there back out to the exterior of the outer leaf of brickwork 25.
[0033] Referring now to Figures 10(a) to 10(d) inclusive and 11(a) to 11(g) inclusive, there
are shown some diagrammatic representations illustrating the known building practices
and more specifically representations illustrating the lack of insulation at the junction
between the gable wall and a single story extension wall (Figures 10(a) to 10(d) inclusive)
as well as some representations illustrating the complexity of insulating the cavity
at this junction in accordance with the known preferred method (Figures 11(a) to 11(g)
inclusive).
[0034] Referring first to Figures 10(a) to 10(d), and initially to Figure 10(d), there is
shown a diagrammatic representation of the junction between a single story extension
and a gable main wall insulated in accordance with current practice. The single story
extension has a roof 51 that abuts against the gable wall 21. The gable wall comprises
an inner leaf of blockwork 23 and an outer leaf of brickwork 25. There is further
provided a plurality of cavity trays (not shown) inserted into the brickwork at a
level just in line with the roof 51 of the single story extension to allow egress
of water out of the cavity 29 between the inner leaf of blockwork 23 and the outer
leaf of brickwork 25 to the exterior of the outer leaf of brickwork 25 and down onto
the roof 51 of the single story extension. The full fill insulation comprises an upper
insulation member 43 and a lower insulation member 41.
[0035] Referring to Figure 10(a), it can be seen that there is a lower layer of block insulation
41 and an upper layer of block insulation 43 with a gap 53 therebetween. The gap 53
is provided to allow for the provision of cavity trays (not shown) mounted on an outer
layer of brickwork (not shown) which will extend inwardly into the gap 53 above the
lower layer of block insulation 41 and below the upper layer of block insulation 43.
The lower layer of block insulation and the upper layer of block insulation 41 are
attached to the inner leaf of blockwork 23. Referring to Figure 10(b), the position
of a plurality of cavity trays 27 relative to the lower and upper layers of block
insulation is shown in the absence of the outer layer of brickwork for clarity. It
can be seen that a portion of the cavity trays, in this case the winged plates 33,
extend inwardly into the gap 53 between the lower and upper layers of block insulation
41, 43. Referring to Figure 10(c), there is shown a view of the cavity wall 21 where
the outer layer of brickwork 25 up to and including the course of bricks that support
the cavity trays in position on the outer leaf of brickwork 25 are shown and finally
referring to Figure 10(d), there is shown a view of the outer leaf of brickwork completed
and the roof 51 of the single story extension in position below the level of the cavity
trays 27 in the gable main wall 21.
[0036] Referring specifically to Figure 10(c), it can be seen that the upper insulation
member 43 terminates just above the cavity trays 27 and that the lower insulation
member 41 terminates just below the cavity trays 27. In other words, the insulation
of the full fill insulation does not extend into the area with the cavity trays 27.
It can be seen that there is a substantial gap 53 between the upper insulation member
43 and the lower insulation member 41. This gap 53 represents a cold thermal bridge
between the exterior of the gable wall 21 and the interior of the gable wall 21. This
cold thermal bridge is highly undesirable for a number of reasons. First of all, the
cold thermal bridge reduces the overall U-value of the insulation for the premises.
Secondly, the lack of insulation can lead to condensation on the uninsulated surface
of the inner wall thereby leading to moisture. This moisture can cause damage, mould
or rot in the building over time and is very difficult and expensive to treat and
rectify. Even though it is highly disadvantageous to not insulate between the cavity
trays, this is typically how the junction with the cavity trays is handled.
[0037] Referring to Figures 11(a) to 11(g) inclusive, there are shown some diagrammatic
representations of the junction between a single storey extension and a two storey
gable main wall insulated in accordance with current recommended best practice, where
like parts have been given the same reference numerals as before. Referring first
of all briefly to Figures 11(e) to 11(g) inclusive, it can be seen that the full-fill
insulation is continuous and there are a number of intermediate insulation slats 61
mounted one on top of the other between the upper insulation member 43 and the lower
insulation member 41. The insulation slats 61 fit between the cavity trays 27 and
each slat must be cut individually on site which is time consuming and difficult to
do. This is typically why the recommended practice is often not followed. The installation
of insulation according to this known method will now be described in more detail
below.
[0038] Referring to Figure 11(a), there is shown the profile shape of the lower insulation
member 41 that illustrates the complexity of the shape that must be cut on site in
order to provide full fill insulation according to the recommended guidelines. The
upper surface of the lower insulation member 41 is cut according to the shape, angle
and spacing of the wings 33 of the cavity trays. Referring to Figures 11(b) and 11(c),
there are shown a pair of views of the insert pieces 63 that must be cut in order
to fit in the void between an adjacent pair of cavity trays 27. The cavity trays 27
have been removed from Figure 11(b) in order to show the insert pieces 63 more clearly
and the cavity trays have been introduced in Figure 11(c) to demonstrate the positioning
of the insert pieces 63 relative to the cavity trays 27. It can be seen that the insert
pieces 63 are merely truncated intermediate insulation slats 61 (such as those shown
in Figures 11(d) to 11(f) inclusive) and usually what would be required is for the
craftsman to cut a piece of insulation to the shape and length of the intermediate
insulation slat 61 as illustrated in Figure 11(d).
[0039] Once the lower insulation member 41 has been cut to the required shape, as illustrated
in Figure 11(a), it is attached to the inner leaf of blockwork 23. The outer leaf
of brickwork 25 is then built up to the level of the first, lowermost, cavity tray
27 (the leftmost cavity tray shown in Figures 11(c)-11(e)), which is then installed
in the usual manner. A first intermediate insulation slat 61 is then cut to shape
and inserted above the first cavity tray 27. Another course of bricks is added to
the outer leaf of brickwork and a second cavity tray is placed above the first cavity
tray, on top of the first intermediate insulation slat 61. A second intermediate insulation
slat 61 is then cut to size and placed above the second cavity tray. A further course
of bricks is added to the outer leaf of brickwork 25 and a third cavity tray is placed
above the first and second cavity trays, and directly above the second intermediate
insulation slat 61. These steps are repeated until all of the cavity trays and intermediate
insulation slats 61 are in position as illustrated in Figure 11(f) (some of the bricks
from the courses of bricks have been removed in order to show the intermediate insulation
slats 61 and a plurality of external DPC members 28 known in the art are mounted on
the outer leaf of brickwork 25). Finally, the remaining bricks in the outer leaf of
brickwork 25 are laid and the single story roof 51 is mounted against the gable wall
21 as shown in Figure 11(g).
[0040] It can be seen from the foregoing description of Figures 11(a) to 11(g) that the
known recommended method of insulating around the cavity trays is highly problematic
due to the complexity of the shapes of insulation, both the lower insulation member
41 and the intermediate insulation slats 61, that must be cut on site to insulate
between and around the cavity trays 27. Accordingly, it is common for the insulation
to be left out at this junction altogether (as described in relation to Figures 10(a)
to 10(d) above) thereby resulting in a cold bridge at that junction.
[0041] Referring now to Figures 12(a) to 12(g) inclusive, there is shown a method of insulating
around the cavity trays 27 in a cavity wall 21 according to the present invention,
where like parts have been given the same reference numeral as before. A cavity tray
insulating member 1 as described in detail above with regard to Figures 1 to 6 inclusive
is used to insulate around the cavity trays 27 at the junction of the two storey gable
wall and the single storey extension roof 51.
[0042] Referring first of all to Figure 12(a), a lower insulating member 41 is cut at an
appropriate angle corresponding to the pitch of the roof (not shown). The lower insulating
member s cut in a straight line rather than in the stepped fashion known in the art
and as illustrated in Figure 11(a) above. This cut is far simpler and quicker to execute.
The lower insulating member 41 is attached to the inner leaf of blockwork 23 in the
known manner.
[0043] Referring to Figure 12(b), one arm 9 of a cavity tray insulating member 1 is bent
inwardly and the cavity tray insulating member 1 is placed above the lower insulation
member 41 with the arm 9 resting on the lower insulation member 41. The cavity tray
insulating member 1 is mechanically fixed in position to the inner leaf of blockwork
23 using one or more tacks 42, only one of which is shown prior to being inserted
into the cavity tray insulating member to secure it in position. Referring now to
Figure 12(c), the outer leaf of brickwork 25 is then built up outside the lower insulation
member 41 and the cavity trays 27 are inserted into the courses of bricks above the
intended junction between the gable wall and the extension roof (not shown). A number
of the bricks from the courses of bricks have been omitted to show the manner in which
the cavity trays 27 are positioned in the outer leaf of brickwork 25 and it can be
seen that the winged plates 33 of the cavity trays extend inwardly into the cavity
towards the trunk 5 of the cavity tray insulating member 1. Once the cavity trays
27 have been inserted into the outer leaf of brickwork 25, the second arm 7 of the
cavity tray insulating member 1 is bent inwardly about the V-shaped groove 11 thereby
forming the channel-shaped body 3 of the cavity tray insulating member 1 (as illustrated
in Figure 12(d)).
[0044] Referring now to Figure 12(e), a DPC 17 is placed over the uppermost arm 7 of the
channel-shaped cavity tray insulating member 1. One leg 19 of the DPC 17 rests against
the inner leaf of blockwork 23 and the other leg 20 of the DPC extends downwardly
over the leading edge of the arm 7 to meet the outer leaf of brickwork 25 and direct
moisture back into the cavity trays 27. An upper insulating member 43 is then cut
at an appropriate angle to correspond to the top surface of the DPC and more specifically
the arm 7 of the cavity tray insulating member 1 before the upper insulating member
43 is attached to the inner leaf of blockwork 23 (Figure 12(f)).
[0045] Finally, referring to Figure 12(g), the outer layer of brickwork 25 and the roof
51 of the single story extension can thereafter be completed. It can be seen from
the foregoing that the amount of cutting and the precision of cutting required are
significantly reduced. In fact, the tradesperson may only need to make two cuts (one
for the upper insulation member and one for the lower insulation member) or indeed
one cut if they use one part of the cut insulating member as the upper insulating
member and the other part of the cut insulating member as the lower insulating member.
A simple straight cut will suffice. All they need to ensure is that the cut made matches
the pitch of the roof. If necessary, one or both ends of the cavity tray insulating
member 1 may also be cut at an angle corresponding to the pitch of the roof so that
the ends are substantially perpendicular to the ground. This will significantly simplify
the process of insulating at this junction and also will significantly speed up the
insulation process. Furthermore, there will be provided a continuous insulation layer
in the cavity which is highly desirable and advantageous and allows for the primary
purpose of the cavity trays to be maintained, namely, the diversion of moisture from
inside the cavity to outside.
[0046] Various other improvements and modifications can be made to the embodiments hereinbefore
described. For example, in the embodiment shown, the V-shaped grooves are cut at an
angle of 90 degrees however one or both V-shaped grooves could be cut at an angle
of greater than 90 degrees which in the case of channel 11 would cause the arm 7 to
be at an acute angle with respect to the trunk and slope downwardly from the inner
leaf of blockwork 23 to the outer leaf of brickwork 25. This facilitates routing any
water on the upper surface of the arm 7 or more specifically the DPC into the cavity
trays. Secondly, in the embodiments shown, the DPC is a separate piece to the cavity
tray insulating member 1. However, it is envisaged that the DPC could be connected
to the cavity tray insulating member 1 as illustrated in Figures 8(a) and 8(b) and
the cavity tray insulating member and the DPC could be transported together. For example,
the DPC 17 could be affixed to the arm 7 along its length so that the DPC can be installed
simultaneously with the cavity tray insulating member. The DPC may be constructed
from a pliable material such as a thin metal strip that can be transported flat and
then bent into the Z-shape configuration on site. In addition to the above modifications,
the inside, lower edge 62 of the upper arm 7 could be chamfered in order to enable
the arm to pivot downwardly about the fold line provided by the V-shaped groove 11
without being interfered with by a brick of the outer leaf of brickwork.
[0047] It is envisaged that the cavity tray insulating member 1 according to the invention
will be provided in a variety of different sizes, including differing lengths, widths,
heights, channel widths and the like to accommodate different sizes of cavity trays
and different pitches of roof, for example. Preferably, the cavity tray insulating
member 1 will be constructed from an insulating material such as EPS, PIR, Phenolic
or other rigid or semi-rigid insulation material. The backing material that acts as
a hinge could be provided by an aluminium laminate. The backing material could be
provided on one or both faces of the cavity tray insulating member and could further
be provided with an adhesive backing to allow it to be stuck onto or applied to the
face of the cavity tray insulating member.
[0048] It is further envisaged that the cavity tray insulating member may comprise a pair
of substantially L-shaped parts that when brought together form the C-shaped channel.
For example, the trunk 5 of the cavity tray insulating member could be divided lengthways,
such as along a central longitudinal axis and the two L-shaped parts would come together,
end to end, along that central longitudinal axis to form the C-shaped channel. In
this way, there would be a two part cavity tray insulating member comprising a lower
cavity tray insulating member and an upper cavity tray insulating member. The lower
cavity tray insulating member would be put in place first with the arm 9 resting on
the board insulation 41 therebelow and the part of the trunk 5 abutting against the
internal blockwork 23. Thereafter, the upper cavity tray insulating member would be
put in place above the lower cavity tray insulating member with the part of the trunk
5 of the upper cavity tray insulating member also abutting against the internal blockwork
23 and resting on top of the part of the trunk 5 of the lower cavity tray insulating
member. The upper and lower cavity tray insulating members may be cut from insulating
material into an L-shape or indeed may be provided from a flat sheet with a cut along
their length, similar to the cuts described above with reference to the C-shaped cavity
tray insulating member, so that the upper and lower L-shaped cavity tray insulating
members may be provided and transported substantially flat and then folded into the
L-shaped configuration on site.
[0049] In a further still embodiment, it is envisaged that instead of a C-shaped channel,
a single L-shaped body could be used where the lower arm 9 could effectively be removed
and instead there would only be an upper arm. Preferably, in such an embodiment the
trunk would terminate in a substantially straight cut through the trunk 5 thereby
providing a flat surface that could rest on the insulation board 41 therebelow. The
upper arm 7 could be provided with a Z-shaped DPC 17 thereon. The L-shaped cavity
tray may be cut from insulating material into an L-shape or indeed may be provided
from a flat sheet with a cut along it's length, similar to the cuts described above
with reference to the C-shaped cavity tray insulating member, so that the L-shaped
cavity tray insulating member may be provided and transported substantially flat and
then folded into the L-shaped configuration on site.
[0050] Throughout the specification, the example used has been of a two storey gable wall
and single storey extension roof. However, it will be understood that this is for
illustrative purposes only and the present invention is not limited to two storey/single
storey junctions but rather any junction where the cavity trays are in place, regardless
of where it may be positioned. It is envisaged that the cavity tray insulating member
according to the invention may be used in other DPC areas such as over heads/lintels
and penetrations. Appropriate modification of the structure of the cavity tray insulating
member may be required in order to suit a specific application however the general
inventive concept remains the same.
[0051] In this specification the terms "comprise, comprises, comprised and comprising" and
the terms "include, includes, included and including" are all deemed totally interchangeable
and should be afforded the widest possible interpretation.
[0052] The invention is in no way limited solely to the embodiments hereinbefore described
but may be varied within the spirit of the invention.
1. A method of insulating around a cavity tray (27) in a cavity wall, the cavity wall
comprising an inner leaf of blockwork (23) and an outer leaf of brickwork (25) defining
a cavity (29) therebetween, and at least one cavity tray (27) to be secured in position
in the cavity on the outer leaf of brickwork, the method comprising the steps of:
(a) placing board insulation (41) in the cavity between the inner leaf of blockwork
and the outer leaf of brickwork up to a level below the intended location of the cavity
tray; characterised in that, the method comprises the additional steps of:
(b) providing a cavity tray insulating member (1) comprising a substantially C-shaped
channel (3) comprising an elongate trunk (5) and a pair of arms (7, 9) bridged by
the trunk and projecting forwardly therefrom, and placing the C-shaped cavity tray
insulating member on top of the insulation (41) in the cavity with one of the forwardly
projecting arms (9) positioned below the intended location of the cavity tray (27)
and the other of the forwardly projecting arms (7) positioned above the intended location
of the cavity tray, with the elongate trunk (5) positioned adjacent to the inner leaf
of blockwork and the free ends of the arms facing towards the outer leaf of brickwork;
and
(c) placing additional board insulation (43) in the cavity on top of the C-shaped
cavity tray insulation member on the forwardly projecting arm (7) positioned above
the intended location of the cavity tray (27).
2. A method as claimed in claim 1 comprising the intermediate step of shaping the cavity
tray insulating member (1) from a substantially flat layer of insulating material
into a C-shaped channel.
3. A method as claimed in claims 1 or 2 comprising the step of securing the C-shaped
cavity tray (1) to the inner leaf of blockwork (23).
4. A method as claimed in any preceding claim comprising the step of, before placing
the additional insulation (43) in the cavity (29) on top of the forwardly projecting
arm (7) of the C-shaped cavity tray (1) that is positioned above the intended location
of the cavity tray, placing a damp proof course (DPC) member (17) on top of that forwardly
projecting arm.
5. A method as claimed in claim 4 comprising the step of placing a Z-shaped DPC member
(17) on the forwardly projecting arm (7), the Z-shaped DPC having a central portion
(18) and a pair of legs (19, 20) protruding outwardly in opposite directions with
respect to each other from the central portion and substantially orthogonally with
respect to the central portion, with one leg (19) of the Z-shaped DPC extending upwardly
along the inner leaf of blockwork (23), the central portion (18) of the Z-shaped DPC
extending forwardly along the forwardly projecting arm (7) and the other leg (20)
of the Z-shaped DPC extending downwardly in front of the forwardly projecting arm
(7) for location between the arm and the outer leaf of brickwork (25).
6. A method as claimed in any preceding claim comprising the step of cutting the cavity
tray insulation member (1) in a straight line across the cavity tray insulation member
and at one end of the cavity tray insulation member, at an angle corresponding to
the pitch of a roof so that the lateral side (12, 14) of the cavity tray insulation
member is substantially orthogonal to the ground.
7. A method as claimed in any preceding claim comprising the step of taping the arm (9)
of the cavity tray insulating member (1) positioned below the intended location of
the cavity tray to the insulation (41) in the cavity therebelow.
8. A method of constructing an insulated cavity wall, the cavity wall comprising an inner
leaf of blockwork (23) and an outer leaf of brickwork (25) defining a cavity (29)
therebetween, and at least one cavity tray (27) secured in position in the cavity
on the outer leaf of brickwork, the method comprising the steps of:
providing an inner leaf of blockwork (23);
providing insulation board (41) on the inner leaf of blockwork to a level below the
intended level of the cavity tray (27);
providing an outer leaf of brickwork (43) to a level below the intended level of the
cavity tray (27);
providing a cavity tray insulating member (1) comprising a substantially C-shaped
channel (3) constructed from an insulating material, the C-shaped channel having an
elongate trunk (5) and a pair of arms (7, 9) bridged by the trunk and projecting forwardly
therefrom;
placing the cavity tray insulating member trunk (3) against the inner leaf of blockwork
(23) adjacent the intended position of the cavity tray (27) in the outer leaf of brickwork
(25) and above the existing insulation board (41) on the inner leaf of blockwork,
the cavity tray insulating member being positioned so that one arm (9) is substantially
below the intended level of the cavity tray and the other arm (7) is substantially
above the intended level of the cavity tray;
providing insulation board (43) on the inner leaf of blockwork above the cavity tray
insulating member;
mounting the cavity tray (27) in position on the outer leaf of brickwork (25) so that
the cavity tray extends inwardly into the cavity between the arms (7, 9) of the cavity
tray insulating member; and
providing the remaining courses of bricks (28) in the outer leaf of brickwork (25).
9. A method as claimed in claim 8 comprising the additional intermediate step of, prior
to providing insulation board (43) on the inner leaf of blockwork above the cavity
tray insulating member, mounting a damp proof course (17) on the uppermost arm of
the cavity tray insulating member.
10. A method as claimed in claims 8 or 9 comprising the intermediate step of shaping the
cavity tray insulating member (1) from a substantially flat layer of insulating material
into a C-shaped channel (3).
11. A cavity tray insulating member (1) for insulating around a cavity tray (27) in a
wall insulation installation, the cavity tray insulating member (1) comprising a substantially
C-shaped channel (3) constructed from an insulating material, the C-shaped channel
comprising an elongate trunk (5) and a pair of arms (7, 9) bridged by the trunk (5)
and projecting forwardly therefrom from a pair of opposing longitudinal sides of the
elongate trunk, and in which the cavity tray insulating member (1) is constructed
from a unitary sheet of insulating material, the unitary sheet of insulating material
having a pair of substantially parallel V-shaped grooves (11, 13) extending along
its length about which the member may be bent from a substantially flat configuration
into the C-shaped channel configuration.
12. A cavity tray (1) as claimed in claim 11 in which the cavity tray has a backing sheet
of flexible material on a face (15) of the body opposite the V-shaped grooves.
13. A cavity tray (1) insulating member as claimed in claims 11 or 12 in which one of
the V-shaped grooves (11, 13) has a groove angle of greater than 90°.
14. A cavity tray (1) as claimed in claims 11 to 13 in which there is provided a damp
proof course (DPC) member (17) connected to one of the arms (7) and extending along
the length of one of the arms.
15. A cavity tray as claimed in claim 14 in which the DPC member (17) is substantially
Z-shaped, the DPC member having a central portion (18) and a pair of legs (19, 20)
protruding outwardly from the central portion in opposite directions with respect
to each other and protruding substantially orthogonally with respect to the central
portion.