You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to structural building decks having drainage systems associated therewith.  
         [0003]     2. Description of Related Art  
         [0004]     Rooftop decks or sun decks are commonly found on buildings, such as residential structures, and generally provide an attractive gathering place with elevated views and sun exposure. However, often such decks can be difficult to maintain due to potential leaking through the deck into a space beneath the deck, such as, for example, when there are indoor living quarters situated beneath the deck. Some conventional methods of addressing deck leaks include coating the decks with waterproofing substances, including coating seams between deck floor planks. Such coatings can detract from the natural or attractive appearance of a deck having visible floor planks. Also, such coatings can require reapplication due to wear.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     Some embodiments of the present invention include deck drainage assemblies, systems, structures and methods of constructing the same. A rooftop deck having a drainage system can comprise a deck frame having floor joists. A plurality of planks can be coupled to the floor joists of the deck to form a floor of the deck and the planks may be visible, such as for aesthetic purposes. Flexible membrane sheets are coupled to the floor joists beneath the floor planks to form drainage channels having curved surfaces between the floor joists and beneath the floor planks. The flexible membranes sheets can comprise substantially water impermeable membranes such as, for example, modified bitumen. The drainage channels can have end portions adjacent a trough (gutter) and the trough can be enclosed within a frame of the roof deck. Also, apertures can be provided on one or more planks of the roof deck with the apertures being sealable using removable plugs. The plugs can be removable to allow insertion of a nozzle to flush or pressure wash the drainage channels beneath the floor of the deck. Also, straps of flexible material, such as nylon straps, can be coupled to the floor joists and extended between the floor joists beneath the drainage channels to provide support for the drainage channels. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0006]      FIG. 1  is a perspective view of a deck comprising an embodiment of the present invention, with the deck disposed atop a building structure.  
         [0007]      FIG. 2  is a partial cutaway perspective view of the embodiment of the present invention of  FIG. 1 , showing drainage channels below floor planks of the roof deck and flexible straps for supporting the drainage channels.  
         [0008]      FIG. 3  is a detail front elevation view of drainage channels and cross members of the deck as viewed from line  3 - 3  in  FIG. 4  (but not showing the trough), with the drainage channels illustrated in partially assembled form comprising roofing felt sheets disposed below modified bitumen sheets that form the drainage channels.  
         [0009]      FIG. 4  is a partial cutaway perspective view of the drainage channels of  FIG. 2 .  
         [0010]      FIG. 5  is a partial perspective cutaway view of the deck of  FIG. 1 , illustrating the trough within an enclosure.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, upon reviewing this disclosure one skilled in the art will understand that the invention may be practiced without many of these details. In other instances, well-known structures associated with decks and building construction have not been described in detail to avoid unnecessarily obscuring the descriptions of the embodiments of the invention.  
         [0012]     Although various embodiments of the present invention are described and illustrated in the context of application to rooftop or sun decks, one skilled in the art will understand after reviewing the present disclosure that the present invention has applicability in a wide variety of structures to reduce or eliminate water leakage, such as, without limitation, building roof structures and other decks, whether disposed on a rooftop or not.  
         [0013]      FIGS. 1-5  illustrate some embodiments of the present invention as applied to rooftop decks. Referring to  FIG. 1 , in those embodiments, a deck  1  can be constructed atop a building structure  22  with the deck having visible floor planks  2 . The floor planks  2  can comprise conventional deck building materials, such as wood, or commonly available composite deck building materials.  
         [0014]     As shown in  FIG. 2 , a frame for the deck can comprise floor joists  10 , and cross-members  12 , which can have ventilation apertures  14 . The cross members can be “bird blocks,” as will be appreciated by those skilled in the art after reviewing this disclosure. In addition, flexible straps  9  of material, such as nylon straps, can be coupled to the floor joists  10  and extend between the floor joists.  
         [0015]     The cross members  12  can have recessed or downwardly curved surfaces on top portions thereof. The flexible straps  9  can hang or droop downward between the floor joists  10 . As can be seen in the embodiment illustrated in  FIG. 4 , flexible membrane sheets  18  can be disposed over the flexible straps  9  and the cross members  12 , with portions of the flexible membrane sheets  18  hanging downward between the floor joists  10  to form curved conduit walls or drainage channels  17 . The sheets of flexible membrane  18  can comprise water impermeable membrane, such as, for example, modified bitumen. The floor joists  10  can be constructed to provide a slight slope that is not noticeable to a user of the deck, but is enough to gravity drain water in the direction of arrows “A” within the channels  17 . Thus, water can leak through seams between the floor planks  2 , into the drainage channels  17  below to be directed away from the building structure  22 .  
         [0016]     As can be seen in  FIG. 3 , each channel  17  in which water can be drained, can be provided using a separate sheet of flexible membrane  18 , with side portions  18   b  of each sheet of flexible membrane overlapping. In addition, a secondary sheet  16 , such as roofing felt, can be placed beneath each sheet of flexible membrane  18 , as will be appreciated by those skilled in the art after reviewing this disclosure. The roofing felt  16  can be used where a torch down method is employed for applying the flexible membrane  18  to seal the overlapping side portions  18   b  of the flexible member sheets  18 . Furthermore, in some embodiments, various available sealant materials, such as tar sealants, can be applied between the layers of the sheets of flexible membrane  18  at the overlapping side portions  18   b  to bind the sheets together and help seal against water leakage. However, again, in some embodiments where the flexible membrane sheets  18  comprise modified bitumen, the flexible membrane sheets  18  can be heated with a torch to seal the side portions  18   b , as will be appreciated by those skilled in the art. Referring now to  FIG. 2 , the planks  2  can be attached to the floor joists  10  by, for example, providing nails that extend through the planks and the flexible membrane sheets  18  into the floor joists  10 .  
         [0017]     In some embodiments of the present invention, a gutter or trough  20  is disposed near end potions  18   c  of the channels  17 , as best seen in  FIG. 4 . The end portions  18   c  of the channels  17  can extend over the trough  20 . The trough  20  can channel water away from the end portions of the channels  17 , such as to a downspout  3 . Also, the trough  20  can be in an enclosure within a planks and sidewalls of the deck, as best seen in  FIG. 5 . In some embodiments, the trough  20  can be removed by being slide outward away from the enclosure, through a side opening adjacent an end cap  7  of the trough  20 .  
         [0018]     Furthermore, as illustrated in  FIG. 5 , in some embodiments of the present invention, one or more of the planks  2  is provided with apertures  6  that extend through the floor planks, with the apertures  6  being capable of being sealed using threaded removable plugs (not shown). In some embodiments, the apertures  6  have diameters between about ½ inch and 3 inches. The removable plugs can be unscrewed to expose the apertures  6  so that a user can insert a nozzle of any of various commercially available flushing or pressure washing device (as will be appreciated by those skilled in the art after reviewing this disclosure) to pressure wash or flush the drainage channels  17  below the deck planks  2 .  
         [0019]     Although specific embodiments and examples of the invention have been described supra for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the invention, as will be recognized by those skilled in the relevant art after reviewing the present disclosure. The various embodiments described can be combined to provide further embodiments. The described devices and methods can omit some elements or acts, can add other elements or acts, or can combine the elements or execute the acts in a different order than that illustrated, to achieve various advantages of the invention. These and other changes can be made to the invention in light of the above detailed description.

Summary:
A deck with a drainage system. The drainage system is comprised of drainage channels formed by a flexible membrane disposed beneath a floor of the deck.