Drainage system for use in building construction

1. A flashing and drainage system for use in cavity wall construction, comprising: a flashing member sized and shaped to be received within a cavity of the wall, said flashing member including a lower flashing portion which is oriented generally horizontally atop a foundation portion of the wall and a upper flashing portion which is oriented generally vertically within the cavity of the wall; a plurality of weep tabs positioned on said lower flashing portion and spaced apart to correspond to weep holes formed through the wall; and a plurality of porous bodies positioned on said upper flashing portion, each of said plurality of porous bodies having a porosity sufficient to permit water to pass therethrough but substantially insufficient to permit mortar and debris to pass therethrough, each of said plurality of porous bodies being positioned to protect a corresponding one of said plurality of weep tabs.

2. The system of claim 1 , wherein said flashing member is formed of one or more of stainless steel, cold-rolled copper, lead-coated copper, galvanized steel, copper laminates, aluminum, EPDM, rubberized asphalt, polyvinyl chloride (PVC) plastic, composite materials and modified bitumen.

3. The system of claim 1 , wherein said flashing member includes backside including a pressure-sensitive adhesive material and a backing material covering said adhesive.

4. The system of claim 1 , wherein said flashing member is rectangular and about 5 feet in length.

5. The system of claim 1 , wherein said weep tabs are formed of one or more of open mesh plastic, cotton, wool and hemp materials.

6. The system of claim 1 , wherein each of said plurality of porous bodies are positioned to prevent occlusion of one or more of said plurality of weep tabs.

7. The system of claim 1 , wherein each of said plurality of porous bodies are a thickness corresponding to distance between inner and outer wythes of the cavity wall.

8. The system of claim 1 , wherein said plurality of porous bodies are formed of a material sufficient to resist compression when under the weight of debris and mortar.

9. The system of claim 1 , wherein each of said plurality of porous bodies is one of square, trapezoid, triangular, inverted trapezoid, triangular, hourglass and wineglass shape.

10. The system of claim 1 , further including a drip edge formed at a distal end of said lower flashing portion.

11. The system of claim 10 , wherein said drip edge is a turned down portion of said lower flashing.

12. The system of claim 10 , where said drip edge is a separate strip of material fixed to said distal end of said lower flashing portion.

13. The system of claim 1 , further including a base portion, sized and shaped to fit underneath said flashing member.

14. The system of claim 13 , wherein said base portion includes a rear dam.

15. The system of claim 14 , wherein said base portion is formed of one or more of stainless steel, cold-rolled copper, lead-coated copper, galvanized steel, copper laminates, aluminum, EPDM, rubberized asphalt, polyvinyl chloride (PVC) plastic, composite materials and modified bitumen.

16. The system of claim 14 , wherein said dam is a raised section of a rear portion of said base portion.

17. The system of claim 13 , wherein said base member includes an extension, for overlapping with an adjacent flashing and drainage system.

18. The system of claim 13 , further including a plurality of corner pieces sized and shaped to cover a corner of a foundation underneath a cavity wall construct and adapted to abut said base portion to form a base for a plurality of said flashing members when said flashing members are placed end to end over said base portions and said corner pieces.

19. The system of claim 18 , wherein said plurality of corner pieces include both outer corner pieces and outer corner pieces.

20. The system of claim 1 , wherein a pair of end dams is formed at opposite ends of said flashing member.

21. The system of claim 1 , wherein a reinforcing member is attached adjacent an upper edge of said upper flashing portion to reinforce said upper flashing portion.

22. The system of claim 1 , wherein each of said plurality of weep tabs is individual strips of material.

23. The system of claim 1 , wherein said plurality of weep tabs are attached at a proximal end to a common body portion of material.

24. A flashing and drainage system for use in cavity wall construction, comprising: a longitudinal base member; a flashing member sized and shaped to be received within a cavity of the wall and over said base member, said flashing member including a lower flashing portion which is oriented generally horizontally atop a foundation portion of the wall and a upper flashing portion which is oriented generally vertically within the cavity of the wall; a plurality of weep tabs positioned on said lower flashing portion and spaced apart to correspond to weep holes formed through the wall; and a plurality of porous bodies positioned on said upper flashing portion, each of said plurality of porous bodies having a porosity sufficient to permit water to pass therethrough but substantially insufficient to permit mortar and debris to pass therethrough, each of said plurality of porous bodies being positioned to protect a corresponding one of said plurality of weep tabs.