Comparative Study of the Effectiveness of Two Wall Drainage Systems Used in Masonry Cavity Wall Construction Test Method: ASTM E-514 (modified) Test Date: December 4, 1994 Test Performed by: Robert L. Nelson & Associates Construction Materials Laboratory (847) 882-1146 Test Results  MortarNet®                                                  First visible water on cavity side of brick..10 minutes Appearance of flowing water on cavity side of brick.................................17 minutes Water passing through weep hole at brick wythe face 3 hours.................................................2.6 gal/hr 72 hours...............................................2.9 gal/hr                     Conclusions This study indicates that the Mortar Net® is clearly superior to pea gravel in allowing water to pass from the cavity to the exterior wall via the weep holes, with a flow rate approximately five times that of pea gravel after three hours and more than twice that of pea gravel after 72 hours. Complete test results are available upon request.