[0001] The invention relates to a device for retaining or collecting and discharging moisture
from or out of a cavity wall having an (outer) leaf of masonry and having an insulation
layer against the inner leaf.
[0002] The outer leaf of the cavity wall particularly through the joints may get saturated
and wet at the inner surface, as a result of precipitation falling on it. This results
in downward transport of water through and past the outer leaf, as well as in the
air space of the cavity. Said water needs to be led out again before it contacts moisture-sensitive
structural members, such as in particular wooden casings or in case of an extension
building, an inner wall formed by an extension of the outer leaf below that outer
leaf.
[0003] Aforementioned devices may be made of a synthetic material and have a flat horizontal
strip lying on a number of bricks of the outer leaf and a rear upturn, extending upwards
at least almost perpendicular from the rear edge of the flat strip. The rear upturn
is meant to abut the insulation layer, in order to thus close off the vertical moisture
transport path in the cavity. It is also known to use a lead flashing, which is accommodated
flat in the outer leaf and extends through the cavity towards the inner leaf, to which
the flashing is attached by nails or in which it is accommodated.
[0004] The thickness dimensions of the outer leaf, the insulation layer and the cavity may
vary, and namely by a difference of some centimetres. As a result it often occurs
that the flat strip extends over some centimetres into the cavity and thus with the
rear upturn forms a collection place for mortar residues or mortar burrs that retain
moisture and may possibly extend against the insulation. It can also occur that the
insulation layer is relatively thick, in which case the flat strip will protrude at
the front side of the outer leaf.
[0005] There are comparable water collection strips in which the rear upturn is flexible
or hingingly connected to the flat strip, with or without the intermediary of a perpendicular
upturn strip from the flat strip. It has appeared however that the pressure force
exerted by the rear upturn on the insulation layer results in a tilting moment on
the (fresh) masonry in the outer leaf of such an extent that the bricks that have
just been laid turn crooked there.
[0006] It is an object of the invention to provide a water collection strip that improves
on that.
[0007] To that end the invention provides a device for retaining or collecting and discharging
moisture from or out of a cavity wall having a leaf, comprising a collection and discharge
strip having a front longitudinal edge and a rear longitudinal edge, in which the
rear longitudinal edge is destined to be situated at the inner or cavity side of the
leaf, and in which the rear longitudinal edge is provided with a rigid rear strip
integrally formed with the collection strip, for collecting moisture and guiding it
to the collection strip, which rear strip extends upwardly inclined from the collection
strip and to the rear.
[0008] With such a design of a water collection device for a cavity wall the differences
in dimensions in the cavity walls can be catered for with one standard product by
letting the rear strip extend or cut into the insulation layer itself, in which the
insulation layer itself functions as leveller in dimensional variations. The edge
of the rear strip can after all without a discernable difference in effectiveness
extend further or less far into the insulation layer. Thus there will always be a
perfect connection between the insulation layer and the rear strip and thus to the
collection and discharge strip. Above and below the insulation layer will be able
to tightly abut the rear strip, so that the insulation value at that location will
not decrease. The incision can easily be made by cutting into the insulation layer
with a blade past the rear edge of the rear strip. The rear edge here serves a ruler.
[0009] Preferably the rear edge extends upwardly inclined and to the rear from the collection
strip at a fixed angle with respect to the collection strip which angle is smaller
than 60 degrees. As a result not only material is economized on, but the placement,
in particularly in renovation construction, is also facilitated.
[0010] Preferably said angle is smaller than 45 degrees, even more preferably smaller than
30 degrees, in particular approximately 20 degrees. The height of the rear strip can
be kept small here, in the order of magnitude of a brick's height.
[0011] Placement is further ensured and facilitated when the device forms a rigid unity.
[0012] It is further preferred that the width of the collection strip is larger than half
a brick's size, preferably larger than 9 cm, preferably a little larger than approximately
11 cm. In this way it is achieved that the collection strip has a width that is larger
than the most common bricks.
[0013] Preferably the rear strip extends rearward over a -horizontal- distance which is
in the order of magnitude of 1/4 to once the width of the collection strip. In this
way it is ensured that the device can be placed in the correct manner in almost all
cavity arrangements possible.
[0014] Placing and adjustment to the actual circumstances is facilitated when the rear edge
is free from parts protruding downwards. The device can be slid from the outside onto
a row of bricks of the outer leaf. In renovation activities removing only one row
of bricks will then suffice.
[0015] Preferably the front longitudinal edge is provided with an integrally formed pending
placement member, which forms a stop when placing the device in/on the outer leaf.
Said pending placement member or placement strip can also be used for connection to
a roofing layer, such as a bitumen layer of for instance an adjacent flat roof.
[0016] For improving the discharge of moisture transverse over the collection strip it preferably
is provided that the collection strip is provided with integrally formed profilings
that are transverse to the length of the strip, that may be situated at any distance
from each other.
[0017] The profilings preferably are shaped like elevations projecting from the upper side,
between which transverse channels have been formed. The channels guarantee discharge
even when there are mortar residues on a portion of the collection strip that extends
in the cavity, in particular underneath those mortar residues.
[0018] The profiling height of the collection strip here is smaller than or equal to the
height of the joint anyway, so that the bed joint height in the outer leaf can remain
constant.
[0019] Preferably the profilings extend beyond the rear longitudinal edge of the collection
strip into the rear strip, as a result of which the angle between both strips is extra
rigid.
[0020] When the profilings end at a distance from the front longitudinal edge, the collection
strip at the outer surface of the outer leaf will only have the height of a strip
thickness and can be covered with a layer of mortar of reasonable thickness.
[0021] Preferably the total thickness of the collection strip at the location of the profilings,
within a distance of half a brick from the front longitudinal edge, is smaller than
or equal to a joint thickness.
[0022] The invention further relates to an assembly of a device according to the invention
and a cavity wall having an inner leaf, an outer leaf of masonry, and a cavity situated
in between them and an insulation layer placed against the inner leaf, at the cavity
side, in which the collection strip has been placed on a horizontal series of bricks
in the outer leaf and with its rear strip extending into the insulation layer. Preferably
the rear strip ends at a distance from the inner leaf. Preferably the profilings extend
in the horizontal joints, between bricks that are situated immediately above each
other.
[0023] The invention further provides a method for placing a device according to the invention
in a cavity wall having an outer leaf of masonry and an insulation layer at the cavity
side of the inner leaf, a horizontal series of bricks being removed from the outer
leaf, the device being inserted into the slit thus created with its rear strip in
the lead until the edge of the rear strip abuts the insulation layer, subsequently
making an incision in the insulation layer along said edge with a blade, pressing
the rear strip into the incision made until the front longitudinal edge comes at the
level of the outer surface of the outer leaf, preferably by means of abutment, and
placing the bricks back in the outer leaf and securing them with mortar. This method
is particularly suitable for renovation building.
[0024] The invention will be elucidated on the basis of an exemplary embodiment shown in
the attached drawings, in which:
Figure 1 shows a water collection strip according to the invention, in isometric view,
having a next identical water collection strip overlapping it;
Figures 2A and 2B show the water collection strip of figure 1 in front view and in
cross-section; and
Figure 3 shows the water collection strip of figures 1 and 2 arranged in a cavity
wall shown in cross-section.
[0025] The water collection strip 1 shown in the figures 1 and 2A,2B is manufactured as
one rigid unity from a synthetic material, such as polyethene or polyvinyl chloride
and comprises a flat moisture discharge/collection strip 2, which at the front edge
merges into a pending placement strip 3. At the rear edge the strip 2 via rigid angled
area 6, merges into a rear strip 4 extending at an angle
α in this example 20° upward and to the rear, which rear strip is provided with a hard
rear edge 5.
[0026] In the angled area 6 profilings or ribs 7 have been formed in the strips 2 and 4,
which are at any -possibly short- distance from each other and extend transverse to
the longitudinal direction of the water collection strip 1 and have inclined walls
8 and between them define discharge channels 9. The ribs 7 end in a tip at both ends.
[0027] As can be seen in figure 2B the upper edges of the ribs 7 run upwardly inclined to
the rear. The ribs 7 form a stiffening of the angled area 6. The collection strip
2 runs horizontally from the placement strip 3 to the rear strip 4. At the lower side
the angled area 6 is free from protrusions.
[0028] In figure 3 the cavity wall 10 is shown, having an outer leaf 11 made of bricks 15
and mortar 16, a brickwork (or glued) inner leaf 12 and a cavity 13 situated in between
them. In the cavity 13 an insulation layer 14 has been arranged against the inner
leaf 12. Between the outer leaf 11 and the insulation layer 14 an air space 13a is
left in the cavity 13.
[0029] Between the bricks 15a and 15b a series of contiguous water collection strips 1 have
been arranged in a direction transverse to the plane of the drawing. The placement
strip 3 here extends along the outside of the bricks 15b, and in this example is provided
with a somewhat turned lower edge 3a, which extends over an edge upturn 16 of a flat
roof 20 covered with a layer of bitumen 21. The flat roof 20 forms the roof of a room
30 situated outside of the cavity wall 11, which room may be an annex garage, shed,
work room or kitchen.
[0030] The collection/discharge strip 2 lies flat on the bricks 15b. With the bottom inner
edge the brick 15a supports on the tops of the ribs 7, and further on a layer of mortar
that has been applied on the strip 2.
[0031] The rearward inclined and upwardly extending rear strip 4 extends in a fitting manner
into the insulation layer 15.
[0032] The water collection strip 1 collects moisture that flows/falls downward in the directions
A and A'. Transversely directed discharge is improved by ribs 7. The discharge to
the outside takes place through the mortar and through open cross joints.
[0033] By way of example the width x of the bricks 15 may be 11 cm, the width of the cavity
s 11 cm as well, the width z of the insulation layer 14 6 cm and the width y of the
air cavity 13a 5 cm. The width of the strip 2 may here be 13 cm and the horizontal
extension of the strip 5 5 cm. The height of the edge 5 is lower than the one of a
brick 15, for instance 3 cm to 6 cm.
[0034] Because the rear strip 4 extends into the insulation layer 4, the connection rear
strip-insulation layer is always perfect, irrespective of the depth over which the
rear strip extends into the insulation layer. In this way -without losing effectiveness-
dimensional differences in the outer leaf, cavity and insulation layer can be compensated,
without additional measures being needed.
[0035] The water collection strip 1 can easily be arranged in the building of new houses
during erection of the outer leaf of a cavity wall. In those cases the insulation
layer will already be fixed to the inner leaf at the level where bricklaying takes
place, with means that are known per se. At the wanted level, where usually a lead
flashing would be arranged, now a series of water collections strip 1 according to
the invention are placed on the then upper row of bricks of the outer leaf, in which
the water collection strips 1 overlap each other, and may also engage into each other
at the location of the ribs 7, as shown in figure 1. As a result the length of the
overlap can be kept short, without there being danger of sideward leaking transport
in the overlap.
[0036] With the help of the rear edge 5 of the rear strip 4 an incision is made in the insulation
layer 14 at the wanted height with a blade that is moved along the rear strip. Because
the water collection strip is rigid the edge 5 can be placed stably at the correct
height along the insulation layer 14. The edge 5 here functions like a kind of ruler
to the blade. By keeping the blade in one plane with the plane of the rear strip 4
as much as possible it can be ensured that the incision has the same direction as
the rear strip 4 in placed position.
[0037] After the incision has been made the water collection strip 1 can be further moved
in the direction of the inner leaf, in which the rear strip penetrates the incision
made, until the pending placement strip 3 abuts the surface of the outer leaf. The
water collection strip 1 then lies in its place and bricklaying the outer leaf can
be proceeded with.
[0038] With the water collection strip according to the invention a water transport barrier
can also be arranged in a cavity wall afterwards in an advantageous manner. This may
for instance be wanted when a lead flashing has to be replaced or when an extension
building has been created to an existing cavity wall. The latter situation is shown
in figure 3.
[0039] Because the water collection strip according to the invention has a low construction
height, lower than the height of brick of the outer leaf, only one layer of bricks
15a needs to be removed from the outer leaf 11 for placing the water collection strip
1. There is sufficient room of movement to make the incision along the rear edge 5
in the insulation layer 14 and to subsequently insert the rear strip 4 into the insulation
layer 14. After that the removed bricks can simply be replaced at their original place
with mortar. The rigid design of the water collection strip 1 facilitates these actions.
[0040] The water collection strip can be stacked in a nesting manner, in which the ribs
are able to fall into each other. When ribs are dispensed with the water collection
strip can be made by extrusion.
1. Device for retaining or collecting and discharging moisture from or out of a cavity
wall having a leaf, comprising a collection and discharge strip having a front longitudinal
edge and a rear longitudinal edge, in which the rear longitudinal edge is destined
to be situated at the inner or cavity side of the leaf, and in which the rear longitudinal
edge is provided with a rigid rear strip integrally formed with the collection strip,
for collecting moisture and guiding it to the collection strip, which rear strip also
extends upwardly inclined from the collection strip and to the rear at a fixed angle
with respect to the collection strip.
2. Device according to claim 1, in which said angle is smaller than 60 degrees, preferably
smaller than 45 degrees.
3. Device according to claim 2, in which the angle is smaller than 30 degrees, in particular
20 degrees.
4. Device according to any one of the claims 1-3, in which the vertical height of the
edge of the rear strip with respect to the lower side of the device is almost equal
to or smaller than the height of a brick in the outer leaf.
5. Device according to any one of the preceding claims, in which the device forms a rigid
unity.
6. Device according to any one of the preceding claims, in which the width of the collection
strip is larger than half a brick's size, preferably larger than 9 cm, preferably
a little larger than approximately 11 cm.
7. Device according to any one preceding claims, in which the rear strip extends rearward
over a -horizontal- distance which is in the order of magnitude of 1/4 to once the
width of the collection strip.
8. Device according to any one of the preceding claims, in which the rear edge is free
of parts protruding downwards.
9. Device according to any one of the preceding claims, in which the front longitudinal
edge is provided with an integrally formed pending placement member.
10. Device according to any one of the preceding claims, in which the collection strip
substantially extends in a planar horizontal plane.
11. Device according to any one of the preceding claims, obtained through extrusion.
12. Device according to claim 10, in which the collection strip is provided with integrally
formed profilings that are transverse to the length of the strip, which profilings
preferably are shaped like elevations projecting from the upper side, between which
transverse channels have been formed.
13. Device according to claim 12, in which the profilings extend beyond the rear longitudinal
edge into the rear strip.
14. Device according to claim 12 or 13, in which the profilings end at a distance from
the front longitudinal edge.
15. Device according to claims 11, 12 or 13 and claim 6, in which the total thickness
of the collection strip at the location of the profilings, within a distance of half
a brick from the front longitudinal edge, is smaller than or equal to a joint thickness.
16. Assembly of a device according to any one of the preceding claims and a cavity wall
having an inner leaf, an outer leaf of masonry, and a cavity situated in between them
and an insulation layer placed against the inner leaf, at the cavity side, in which
the collection strip has been placed on a horizontal series of bricks in the outer
leaf and with its rear strip extending into the insulation layer.
17. Assembly according to claim 16, in which a device according to any one of the claims
12-15 is being used, in which the profilings extend in the horizontal joints, between
bricks that are situated immediately above each other.
18. Assembly according to claim 16 or 17, in which the rear strip ends at a distance from
the inner leaf.
19. Method for placing a device according to any one of the claims 1-15 in a cavity wall
having an outer leaf of masonry and an insulation layer at the cavity side of the
inner leaf, a horizontal series of bricks being removed from the outer leaf, the device
being inserted into the slit thus created with its rear strip in the lead until the
edge of the rear strip abuts the insulation layer, subsequently making an incision
in the insulation layer along said edge with a blade, pressing the rear strip into
the incision made until the front longitudinal edge comes at the level of the outer
surface of the outer leaf, preferably by means of abutment, and placing the bricks
back in the outer leaf and securing them with mortar.