03/09/2026
Sizing roof drains off roof area alone? That is how job-site delays happen.
Ignoring vertical parapet walls understates your catchment area by 30% or more.
That is a direct path to choked drains and flooded sites.
Before signing off on your hardware schedule:
☑ Factor in wind-driven wall runoff
☑ Re-verify flow rates against true wall heights
☑ Size primary drains for peak storm loads
Protect your project timeline. Double-check the wall math today. Link in the comments below.