How Do You Waterproof a Roof Over Type B Metal Deck in Florida?
The deck is not the waterproofing. Over 1.5" Type B, a roof stays dry through a membrane system (single-ply, modified bitumen or built-up) installed over insulation or a cover board, with well-detailed drains, sump pans and flashings. In Florida that system needs approval for the project's wind zone. We supply the deck, sump pans and accessories the roofing detail calls for.
Reliable membrane approaches
- Single-ply membranes (such as TPO or PVC), mechanically attached through the insulation into the deck, or adhered.
- Modified bitumen or built-up roofing over a cover board.
- Membranes over lightweight insulating fill on vented Type B, where the fill provides a smooth, sloped base.
Where water gets in
Leaks usually start at drains, curbs, penetrations and edges, not in the field of the roof. Recessed sump pans at drains are standard from us; sloped sump pans come when specified. Frame and flash every opening as detailed. Under Florida rules, the membrane, insulation and fastening must match an approved assembly, and in Miami-Dade and Broward that approval must cover the High-Velocity Hurricane Zone.
Protect the deck during construction
Dry in quickly; insulation laid on a wet deck traps moisture. Choose G90 galvanizing where moisture exposure is likely. Send your roof plan and we will quote deck, sump pans and accessories together.
Related Questions
Do I need a vapor retarder over Type B deck?
It depends on the building use and climate. Cold, dry interiors in Florida's heat, like coolers or data rooms, can drive moisture toward the roof, and the roof designer may add a vapor retarder on the deck or over a board. Typical offices often do not. The roof designer decides based on the assembly.
What accessories does a Type B roof need around drains?
Drains typically sit in sump pans that lower the deck surface at the drain. Our recessed level sump pan is standard and a sloped pan is furnished when specified. Accessories ship in 10' lengths and only when ordered, so list them on the takeoff along with closures and flashing angles.