Water collection strip

Abstract: 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.

Description: The invention relates to an assembly of 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, and a device for collecting and discharging moisture from or out of the cavity wall, as described in the preamble of claim 1. Such an assembly is known from GB-A-1.007.225. The known device has a collection strip and a rear strip and at the ends of the device transverse walls having wings that project upwardly and rearwardly of the top of the rear strip. When placed in the cavity wall the device abuts against the cavity side of the inner leaf. In general, 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. Known 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. 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. 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. It is an object of the invention to provide a water collection strip that improves on that. To that end the invention provides an assembly as described in claim 1. 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. In a preferred embodiment of the assembly according to the invention the rear strip 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. 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. Placement is further ensured and facilitated when the device forms a rigid unity. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. The invention further provides a method for placing a device as part of the assembly according to the invention in the cavity wall having an inner leaf and an outer leaf of masonry and an insulation layer at the cavity side of the inner leaf, in which the device is placed on the outer leaf and moved towards the insulation layer with its rear strip and rear edge thereof in the lead until the rear edge of the rear strip abuts the insulation layer, in which subsequently an incision in the insulation layer is made along said rear edge with a blade, the rear strip is pressed with its rear edge in the lead into the incision made and into the insulation layer until the front longitudinal edge comes at the level of the outer surface of the outer leaf, preferably by means of abutment. Preferably, at a level of the outer leaf a horizontal series of bricks is being removed from the outer leaf, the device is inserted into the slit thus created, and after the rear strip has been inserted into the insulation layer the bricks are placed back in the outer leaf and secured with mortar. This method is particularly suitable for renovation building. 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. 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. 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. 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. 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. 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. 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. The rearward inclined and upwardly extending rear strip 4 extends in a fitting manner into the insulation layer 15. 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. By way of example the width x of the bricks 15 may be 1 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. 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. 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. 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. 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. 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. 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. 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.

Claims: Assembly of a cavity wall having an inner leaf (12), an outer leaf (11) of masonry, and a cavity situated in between them, and a device (1) for retaining or collecting and discharging moisture from or out of the cavity wall, the device comprising a collection and discharge strip (2) placed on a horizontal series of bricks in the outer leaf (11) and having a front longitudinal edge and a rear longitudinal edge, in which the rear longitudinal edge is situated at the inner or cavity side of the outer leaf (11), and in which the rear longitudinal edge is provided with a rigid rear strip (4) integrally formed with the collection strip (2), 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), characterized in that an insulation layer (14) has been placed against the inner leaf (12), at the cavity side, and in that the rear strip (4) ends in a rear edge (5) which is inserted in the insulation layer (14). Assembly according to claim 1, in which in the device (1) said angle is smaller than 60 degrees, preferably smaller than 45 degrees. Assembly according to claim 2, in which in the device (1) the angle is smaller than 30 degrees, in particular 20 degrees. Assembly according to claim 1, 2 or 3, in which in the device (1) the vertical height of the rear edge (5) of the rear strip (4) with respect to the lower side of the device (1) is almost equal to or smaller than the height of a brick in the outer leaf. Assembly according to any one of the preceding claims, in which the device (1) forms a rigid unity. Assembly according to any one of the preceding claims, in which the width of the collection strip (2) is larger than half a brick's size, preferably larger than 9 cm, preferably a little larger than approximately 11 cm. Assembly according to any one preceding claims, in which the rear strip (4) extends rearward over a -horizontal- distance which is in the order of magnitude of 1/4 to once the width of the collection strip (2). Assembly according to any one of the preceding claims, in which the rear edge (5) of the device (1) is free of parts protruding downwards. Assembly according to any one of the preceding claims, in which the front longitudinal edge of the device (1) is provided with an integrally formed pending placement member (3). Assembly according to any one of the preceding claims, in which the collection strip (2) of the device substantially extends in a planar horizontal plane. Assembly according to any one of the preceding claims, in which the device (1) is obtained through extrusion. Assembly according to claim 10, in which the collection strip (2) of the device is provided with integrally formed profilings (7) that are transverse to the length of the strip (2), which profilings preferably are shaped like elevations projecting from the upper side, between which transverse channels (9) have been formed. Assembly according to claim 12, in which the profilings (7) extend beyond the rear longitudinal edge of the collection strip (2) into the rear strip (4). Assembly according to claim 12 or 13, in which the profilings (7) end at a distance from the front longitudinal edge. Assembly according to claims 11, 12 or 13 and claim 6, in which the total thickness of the collection strip (2) at the location of the profilings (7), within a distance of half a brick from the front longitudinal edge, is smaller than or equal to a joint thickness. Assembly according to any one of the claims 12-15, in which the profilings (7) extend in the horizontal joints (16), between bricks that are situated immediately above each other. Assembly according to any one of the preceding claims, in which the rear strip (4) ends at a distance from the inner leaf (12). Method for placing a device (1) as part of the assembly according to any one of the claims 1-17 in the cavity wall (10) having an inner leaf (12) and an outer leaf (11) of masonry and an insulation layer (14) at the cavity side of the inner leaf (12), in which the device is placed on the outer leaf and moved towards the insulation layer (14) with its rear strip (4) and rear edge (5) thereof in the lead until the rear edge (5) of the rear strip abuts the insulation layer (14), in which subsequently an incision in the insulation layer (14) is made along said rear edge (5) with a blade, the rear strip (4) is pressed with its rear edge (5) in the lead into the incision made and into the insulation layer (14) until the front longitudinal edge comes at the level of the outer surface of the outer leaf (11), preferably by means of abutrrient. Method according to claim 18, in which at a level of the outer leaf a horizontal series of bricks is being removed from the outer leaf, the device is inserted into the slit thus created, and after the rear strip (4) has been inserted into the insulation layer (14) the bricks are placed back in the outer leaf and secured with mortar.

Inventors: VAN ROOIJ JACOB, VAN SCHELLEBEEK DIRK JOHANNES, VAN ROOIJ, JACOB, VAN SCHELLEBEEK, DIRK JOHANNES
Applicants: UBBINK B V, UBBINK B.V.
Application year: 2001
Main classification: E04B1
IPC codes: E04B1