Patent Publication Number: US-7216460-B2

Title: Drainage system for use in masonry block construction

Description:
FIELD OF THE INVENTION 
   This invention relates to concrete masonry unit wall construction and, more particularly, to a drainage system therefor. 
   BACKGROUND OF THE INVENTION 
   Single wythe masonry walls are constructed using concrete masonry units (CMUs). CMUs are sometimes referred to as cinder blocks. A CMU consists of a hollow rectangular building block having one or more vertical cavities. In single wythe masonry wall construction a foundation is formed, typically of concrete. The wall is formed by laying the CMUs in alternating fashion in multiple courses depending on the height of the wall. Owing to the construction, the vertical cavities of CMUs are aligned to provide a continuous channel from the top of the wall down to the foundation. Mortar is used in joints to join the CMUs. 
   Cracks in the CMUs can allow water to enter the cavities. Moisture can also condense in the cavities under changing temperatures. Either way, water may collect in the cavities in the CMUs. 
   The presence of moisture in the cavities is undesirable for a number of reasons. First, the trapped moisture can degrade the structure. Second, the presence of water under freezing temperatures may also cause cracks in the wall when water expands as it freezes. Trapped water in the cavities in the CMUs may cause the CMUs to become discolored, and may even migrate into the dwelling. 
   To overcome the problems associated with water trapped within the CMU cavities, weep holes are commonly included along the base of the outer side of the CMUs in the lowermost course. The weep holes allow water to pass from the cavity to drain outside the wall structure. A flashing disposed in the cavity directs the collected water toward the weep holes. 
   During construction of a single wythe masonry wall, excess mortar and other debris can and does fall into the cavities. When the CMUs are stacked during the erection of the wall, for example, mortar droppings are squeezed into the cavities within the CMUs. The excess mortar, as well as other debris, drops to the base of the cavity, and can block weep holes. 
   One known solution is to construct a CMU drainage course consisting of two wythes separated by a cavity sized to accommodate through wall flashing and blocks of water permeable material. This solution uses different style concrete blocks in the drainage course. 
   Another known solution, shown in U.S. Pat. No. 6,202,366, uses a collection pan under each CMU cavity to collect water in the cavity. A weep channel on the pan drains the water to the exterior of the wall. This solution requires a collection pan for each vertical cavity. 
   The present invention is directed to solving one or more of the problems discussed above, in a novel and simple manner. 
   SUMMARY OF THE INVENTION 
   In accordance with the invention, there is provided a drainage system for use in concrete masonry unit (CMU) wall construction. 
   Broadly, the drainage system comprises an elongate flashing member having a width similar to width of CMUs, to be received beneath a course of the CMUs, in use. A layer of water permeable material is attached to an upper surface of the flashing member. The layer of water permeable material includes a longitudinal portion extending longitudinally adjacent a rear edge of the flashing member and a plurality of longitudinally spaced transverse portions extending transversely from the longitudinal portion to a front edge of the flashing member. A plurality of blocks of water permeable material are provided, each being positioned above the layer of water permeable material and extending upwardly into cavities of the CMUs, in use. The water permeable material of the layer and the blocks have a porosity sufficient to permit water to pass therethrough but substantially insufficient to permit mortar and debris to pass therethrough so that water in cavities of the CMUs drains through the transverse portions. 
   It is a feature of the invention that the layers and the blocks are of the same type of water permeable material. The water permeable material may be a non-water absorbent randomly oriented fibrous material. 
   It is a feature of the invention that the blocks may be pyramidal or triangular. 
   It is another feature of the invention that the layer is in the range of ⅛ to ½ inch thick. Advantageously, the layer is about ¼ inch thick. 
   It is another feature of the invention that the transverse portions are spaced in the range of two to eight inches apart. The transverse portions may be about one inch across. 
   It is another feature of the invention to provide an elongate bar underneath the rear edge of the flashing member to channel water through the longitudinal portion to the transverse portions. A pair of transverse bars may also be provided underneath opposite longitudinal ends of the flashing member to channel water toward the front edge. 
   It is a further feature of the invention that the blocks comprise perforated tubes. 
   It is yet another feature of the invention that the blocks comprise rolls of fibrous mesh. 
   It is still another feature of the invention that the blocks are in contact with the layer of water permeable material. 
   There is disclosed in accordance with another aspect of the invention a drainage system for use in single wythe masonry wall construction formed by courses of CMUs each having vertical cavities. The drainage system comprises an elongate flashing member having a width similar to width of the CMUs, to be received beneath a course of CMUs, in use. An elongate bar is underneath a rear edge of the flashing member to define a dam at an interior side of the single wythe masonry wall. A layer of water permeable material is attached to an upper surface of the flashing member. The water permeable material includes an elongate longitudinal portion extending longitudinally outwardly of the dam and a plurality of transverse portions extending transversely from the longitudinal portion to a front edge of the flashing member. A plurality of blocks of water permeable material are each supported on the layer of water permeable material and extend upwardly into cavities of the CMUs, in use. The water permeable material of the layer and the blocks has a porosity sufficient to permit water to pass therethrough but substantially insufficient to permit mortar and debris to pass therethrough so that water in cavities of CMUs drains through the transverse portions. 
   Further features and advantages of the invention will be readily apparent from the specification and from the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exterior perspective view of a drainage system in accordance with the invention used in a single wythe masonry wall formed by courses of concrete masonry units (CMUs); 
       FIG. 2  is a plan view of a flashing member with a layer of water permeable material in accordance with the invention; 
       FIG. 3  is an exterior perspective view of an elongate bar and the flashing material of  FIG. 2  mounted to a wall foundation; 
       FIG. 4  is an interior perspective view of the elongate bar and the flashing material of  FIG. 2  mounted to a wall foundation; 
       FIG. 5  is an exterior perspective view illustrating the drainage system in accordance with the invention mounted on a foundation; 
       FIG. 6  is a perspective view of an alternative embodiment of the drainage system in accordance with the invention used in a reinforced single wythe masonry wall construction; 
       FIG. 7  is a perspective view of a block of water permeable material according to an alternative embodiment of the invention; 
       FIG. 8  is a perspective view of a block of water permeable material according to a further alternative embodiment of the invention; and 
       FIG. 9  is a perspective view of a block of water permeable material according to yet another alternative embodiment to the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a drainage system  10  is illustrated in connection with a concrete masonry unit (CMU) wall construction. In the illustrated embodiment of the invention, the drainage system  10  is used in a single wythe masonry wall construction  12  formed by courses  14  of CMUs  16 . The wall construction  12  is used on a building structure including a foundation wall  18  with an interior floor  20  inside the foundation wall  18  and exterior grade  22  outside the foundation wall  18 . In the illustrated embodiment of the invention, the foundation wall  18  comprises a concrete wall. The foundation wall could be of block construction, as will be apparent to those skilled in the art. 
   Referring also to  FIGS. 1 and 5 , the drainage system  10  comprises a flashing member  24 , an elongate bar  26 , a layer  28  of water permeable material and a plurality of blocks  30  of water permeable material. 
   CMUs  16  are typically about 16″ long wide and come in nominal widths of eight, ten and twelve inches. The CMU  16  comprises a concrete block  32  having a pair of vertically extending cavities  34  therethrough. In conventional single wythe masonry wall construction, a first course  14 - 1  of CMUs  16  is secured to the foundation wall  18  with a layer of mortar. Mortar is also provided between adjacent CMUs  16 . A layer of mortar is then placed upon the first course  14 - 1  and the second course  14 - 2  is laid on the first course  14 - 1 . Again, mortar is provided between each CMU  16 . The CMUs  16  in each course are typically offset from one another as illustrated in  FIG. 1 . As a result, the vertical cavities  34  in any one course  14  are aligned with the vertical cavities  34  in other courses to provide a continuous channel from the top of the wall down to the foundation wall, as is well known. 
   Referring to  FIG. 2 , the flashing member  24  comprises an elongate body  36  of flashing material. The body may be formed of plastic or sheet metal or the like. In the illustrated embodiment of the invention, the flashing member  24  comprises a peel and stick material. As such, an adhesive layer is provided on an underside of the body  36 . The body  36  is defined by an inner or rear edge  38 , an outer or front edge  40  and opposite longitudinal ends  42  and  44 . Width of the body  36  is similar to width of the CMUs. The body  36  has a length sufficient to extend at least across a single cavity  34  or advantageously to extend the entire length of the foundation wall  18 . 
   The layer  28  of water permeable material includes an elongate rectangular longitudinal portion  46  and a plurality of longitudinally spaced shorter, rectangular transverse channel portions  48  extending outwardly therefrom. As used herein, the relative term inner refers to the inner side of the foundation wall, i.e. the rear edge  38  of the flashing member  24 , and outer refers to the outer side of the foundation wall, or the front edge  40  of the flashing member  24 . 
   The layer  28  is adhered to a top surface  50  of the flashing member  24 , such as by using a suitable adhesive. The longitudinal portion  46  is disposed outwardly adjacent the rear edge  38  at least one inch frontwardly of the rear edge  38 . The transverse channel portions  48  extend transversely from the longitudinal portion  46  to the front edge  40  of the flashing member  24 . The transverse channel portions  48  are approximately one inch across and are spaced apart in the range of two inches to eight inches, as necessary or desired. The layer  28  has a thickness in the range of about ⅛ inch to ½ inch with ¼ inch being typical. The longitudinal portion  46  serves to interconnect the transverse channel portions  48 . In accordance with the invention, the layer  28  could be provided without the longitudinal portion  46  and use only individual transverse channel portions  48  extending to the front edge  40   
   In the illustrated embodiment of the invention, the water permeable material used in the layer  28  functions to permit water to pass therethrough and to substantially prevent mortar and other debris from passing therethrough. The material is preferably a non-absorbent water-permeable, fibrous mesh material formed with circuitous (non-linear) pathways. The material is preferably a massive random filament-type plastic fibers with a density which is sufficient to catch and support mortar and other debris thereon without significant collapse, but allow water to pass freely therethrough. A preferred embodiment of the material is a polyethylene or polyester fibrous mesh such as ENKAD-RAIN  9120  normally manufactured by Akzo Industries. The layer  28  may be provided as one piece or the transverse channel portions  48  may be provided separate from the longitudinal portion  46 , as desired. The layer  28  may also be formed of a perforated tubular or cylindrical material. 
   Alternatively, the water permeable material could be made by a partial-fusion process which fuses closed-cell propylene or polyethylene beads together at the tangents of the beads. In this case water would flow between the beads in noncontacting areas. 
   Referring also to  FIG. 3 , the elongate bar  26  consists of ¼ inch high bar stock of plastic placed along the foundation wall  18  near an interior side  52 . The flashing member  24 , a portion of which is shown in  FIG. 3 , is adhered to the foundation wall  18  with the rear edge  38  raised and overlying the elongate bar  26  to define a dam at the interior side  52  of a single wythe masonry wall. Due to the self adhering nature of the underside of the flashing member  24 , the flashing member  24  adheres to the top of the foundation  18  and to the bar  26 . 
   In the illustrated embodiment to the invention, the elongate bar  26  is used in combination with the flashing member  24  to define a dam, as described. Alternatively, other devices could be used to raise the rear edge to define a dam. Additionally, the foundation wall could be “L” shaped as by having a continuous ridge proximate its rear edge. The flashing member  24  can then be formed or is placed on the foundation to adapt to the foundation shape and thus similarly provide a dam at the interior side of the masonry wall. 
   Thereafter, the first course  14 - 1  is constructed in the conventional manner applying mortar between the first course  14 - 1  and the flashing member  24 . As such, the first course  14 - 1  is constructed on top of the flashing member  24  and layer  28 . At least some of the transverse channel portions  48  are generally centered in the cavities  34  and serve to create weep holes within the mortar joint. If mesh material is used, the transverse channel portions  48  may be provided with suitable reinforcement such as solid plastic rods or the like to accommodate the load of the CMUs  16 . 
   Referring to  FIG. 5 , the blocks  30  comprise wedge blocks and are preferably triangular or pyramid shaped and are of a water permeable material. The wedge blocks  30  could be of other shapes, such as conical or trapezoidal, or the like. The water permeable material may be the same material that is described above relative to the layer  28 . In the illustrated embodiment of the invention, the blocks  30  are in the range of eight inches to sixteen inches tall and about two inches thick. The lower end has a width corresponding generally to the width of the CMU cavities  34 . Subsequent to laying of the first course  14 - 1 , the blocks  30  are placed in the cavities  34  and are positioned above the layer  28 . This can be done by the blocks  30  being wedged in the cavities  34  or by the blocks  30  directly resting on the layer  28 . Alternatively, the wedges  30  could be attached to the flashing member  24  or to the layer  28 . As an alternative to the triangular wedge fiber mesh design, the blocks could consist of rolls  30 - 1 , see  FIG. 7 , of fiber mesh material, as above. Also, the blocks could consist of perforated tubes  30 - 2 , see  FIG. 8 , of plastic or the like. Other shape tubes could also be used. Still a further alternative block  30 - 3  is illustrated in  FIG. 9 . The block  30 - 3  comprises a parallelepiped head piece  70  of fiber mesh material, as above. The size of the piece  70  corresponds to the size of the block cavities  34  to be received therein. The piece  70  includes a pyramid shaped hollowed area  72  extending from a relatively small square shaped top opening  74  to a relatively large square shaped bottom opening  76 . As is apparent, other hollowed out shapes could be used, such as square or rectangular, or the like, as will be apparent to those skilled in the art. As above, the block  30 - 3  would be positioned above the flashing member  24 . 
   In accordance with the invention, water in the CMU cavities  34  is channeled downwardly through the triangular wedges  30  and subsequently to the layer  28 . Within the layer  28 , the water is channeled to the transverse channel portions  48 , either directly or through the longitudinal portion  46 , where the water is channeled to the exterior of the foundation  18 . 
   Referring to  FIG. 6 , rebar  60  may extend vertically from the foundation wall  18 . For these applications ¼ inch plates  62  are positioned either side of each rebar  60  outwardly of the elongate bar  26 . The flashing member  24  is cut to fit between the rebars  26  and the opposite ends  42  and  44  are raised up by the plates  62  to dam water that is then channeled out the front edge  40  of the flashing member  24  via the strips  48 , as above. 
   Thus, in accordance with the invention, there is provided a single sheet-like product which serves as a flashing and a continuous drainage system that allows water to have an exit along substantially the entire length of the product. In so doing, the possibility of ponding is eliminated and ventilation of the cavities  34  is increased. The installation of the combination flashing and mortar and debris collection devices and system of the present invention require no adhesives or attachments other than that normally associated with conventional flashing installations.