Roof Zone Mapping in Orlando, FL

Capability

FBC Wind-Pressure Zone Definitions for Orlando Commercial Roofs

Florida Building Code Chapter 15 and ASCE 7-22 define three roof pressure zones for commercial low-slope roofs: the field zone (Zone 1), the perimeter zone (Zone 2), and the corner zone (Zone 3). Each zone carries a higher design uplift pressure than the interior zone, reflecting the turbulence and vortex effects that develop at roof edges and corners under wind loading.

For a typical 30-foot-tall commercial building in Orlando's Wind Speed map zone (approximately 130 mph 3-second gust at OIA), the design pressures run roughly -25 to -30 psf in the field, -45 to -55 psf in the perimeter zones, and -65 to -85 psf in the corner zones — numbers that drive significantly different fastener patterns and attachment densities in each zone. A zone diagram for an Orlando commercial building maps the physical boundaries of these zones on the actual roof plan, so that the specification for each zone can be applied correctly during installation and verified during inspection.

Buildings on the east and northeast exposure to Lake Eola, buildings in the Kissimmee Valley area where open terrain extends the effective wind exposure, and buildings on International Drive near the elevated topography around the conventions center all have exposure considerations that affect the zone boundaries. We calculate exposure category and zone boundaries from the building's actual location and surrounding terrain, not from a generic template.

What the Zone Diagram Labels

Roof zone boundaries: Field, perimeter, and corner zones with dimensions from the building edge per ASCE 7 — the perimeter zone width is a function of the smaller of the building's horizontal dimension or its eave height, so it varies by building geometry. We calculate these dimensions and draw them on the plan.

Drains: Every drain is labeled (D-1, D-2, etc.) with its approximate area of contribution and condition noted in the inspection report. Orlando building drain layouts are the most important planning document for understanding ponding risk — the zone diagram shows us immediately whether the drain layout matches the roof's geometry or whether certain areas are effectively draining away from the drains.

HVAC curbs and equipment: Every HVAC curb, unit, pipe penetration, skylight curb, vent, and equipment pad is labeled. The curb count and location matters for scheduling — replacing a roof under 30 HVAC curbs requires a different production sequence than replacing a roof with 8 curbs. Knowing the locations before the project starts means we plan the curb-flashing work into the critical path, not as an afterthought.

Expansion joints and parapet walls: Interior expansion joints and parapet wall locations are labeled. In Central Florida, where karst geology under much of Orange County produces measurable foundation movement, expansion joints in older buildings often show progressive separation that is tracked across multiple inspection cycles. Without the zone diagram, we cannot quantify progression — a joint that has opened from 0.5 inch to 0.75 inch between inspections is data; 'the expansion joint looks worse' is not.

Zone Diagrams for Multi-Building Portfolios

For portfolio owners managing multiple buildings across the Orlando metro, a standardized zone diagram format across all buildings is the difference between a portfolio management system and a collection of building-specific records that cannot be compared. We produce zone diagrams in a consistent format across all buildings in a portfolio, with a consistent labeling convention that a facilities team can navigate without re-learning the system for each building.

We have produced zone diagram sets for hotel portfolios on International Drive where 15-25 buildings share a consistent format, for office park owners in the Maitland and Sand Lake Road corridors managing 10-20 buildings on a single asset management contract, and for medical office operators in the Lake Nona area managing buildings across multiple campuses. A portfolio zone diagram set is the foundational document that makes portfolio-level condition reporting and capital planning possible.

The zone diagrams we produce are property of the building owner. They are not proprietary to our engagement. If the building owner changes contractors, the zone diagram goes with the building — it is a building record, not a contractor marketing document. We include this provision in every engagement because zone diagrams should be maintained for the life of the building, not lost when a contractor relationship changes.

Frequently asked questions