Plaza Drainage and Drain Details
In a perfect world all plazas should sheet flow at 1 % away from the building ’ s finish floor . Do to inconsistencies in hardscape surfaces , water needs . 5 % minimum fall and due to ADA path of travel requirements , plazas need to be less than 2 % in cross fall . If sheet fall is not possible , slot drains can be added that work in a sheet flow type of scenario . If project doesn ’ t allow for slot drains and sheet flow then area drains need to be incorporated into the design . We prefer that if area drains are used , the substructure needs to be analyzed to make sure the piping and drain bodies will miss and clear any structural items below the hardscape surface and that the design fits . The design needs to interface and include construction joints and saw cut patterns , reinforcing schedules and any other imbedded items . All plazas constructed need to be in geometric shapes . Therefore the ridge lines need to fall on saw cut pattern lines or preferably on cold or construction joints . The drain body works best if it is laid out and installed directly in the middle of a panel and where the pattern is as close to square as possible . In plan view ( see shop drawing ) if the short leg of a hardscape pattern is 1.5 % and the angle is a true 45 degrees than the long leg or hypotenuse will be at 1 %. Any other angles will greatly affect the percentage of fall depending on how great or less the angle is . In general , if the angle becomes more obtuse or acute it will dramatically change the percentage of the surface requirements and allowances .
240
Shaw & Sons has always provided the best service in : drainage locations , Leica total station layout , adjusting grades , elevations and combining them with our precision engineering and workmanship to create superflat plazas and surfaces .