Sets the building's importance (ASCE 7-22 Table 1.5-1). I — low hazard to human life (barns, minor storage, no occupancy). II — standard occupancy: most homes, offices & retail (the usual choice). III — substantial hazard: schools, day-cares, assembly for >300 people, buildings with large occupant loads. IV — essential facilities that must stay operational: hospitals, fire/police/EOC, power & water utilities. When unsure, II covers ordinary buildings; step up to III for schools/assembly and IV for critical facilities.

Which basic wind speed V you're working in. Ultimate — strength-level (LRFD); the ASCE 7-22 wind maps give ultimate speeds, so this is the map value used directly with strength load combinations. Nominal — service / allowable-stress (ASD) level (≈ ultimate × 0.78), used with ASD load combinations. Pick the one that matches your design method. Residential ASD work commonly uses Nominal; LRFD/strength design uses Ultimate.🌴 Florida (FBC) — Components & Cladding: The Florida Building Code (8th Ed., 2023) adopts ASCE 7-22. For C&C — including roof C&C — design pressures may be taken at Nominal (ASD) level, matching the allowable-stress design pressures listed on Florida product approvals & Miami-Dade NOAs. The wind maps give ultimate speeds, so Nominal ≈ ultimate × 0.78.

Ground roughness around the site (ASCE 7-22 §26.7). B — urban, suburban or wooded areas with numerous closely-spaced obstructions (houses, trees). C — open terrain with scattered obstructions under 30 ft: flat open country, grassland (a common, conservative choice). D — flat, unobstructed areas & water surfaces: shorelines in hurricane-prone regions, mud/salt flats. Use the roughness that actually surrounds the building; when a site straddles two, the rougher upwind fetch governs.

Determines the internal pressure GC_pi (set automatically; ASCE 7-22 §26.2 & §26.12). Enclosed — no dominant openings (a typical finished building). Partially Open — some openings, but not enough to be partially enclosed. Partially Enclosed — a dominant opening on one wall (large door, or failed glazing) lets wind pressurize the interior — a big uplift increase. Open — each wall is ≥ 80% open (canopies, pavilions). In a wind-borne-debris region, glazing that isn't impact-rated may have to be treated as an opening.

Building width/length set the edge-strip dimension a. Mean roof height h is the average of eave and ridge. Roof slope is X/12 rise-over-run (shown in degrees) — each roof shape has its own valid range. Enter the component (tributary) area and roof zone on the Calculator step.

Flat terrain → no speed-up (K_zt = 1.0). For a 2D ridge, 3D axisymmetric hill, or escarpment, enter the feature height H, the half-length L_h (crest to where the ground is half of H), and x (crest to the building — upwind negative, downwind positive). Leave as Flat for level sites. This factor feeds q_h = 0.00256·K_z·K_zt·K_d·K_e·V².

Add a row per roof component. Each row's effective wind area (Width × Length) and ± design pressures recompute instantly. Zone 1 = interior, Zone 2 = edge, Zone 3 = corner (highest uplift) — set each row's zone with the ▲▼ arrows. Factors below (q_h, K's, edge strip a) come from the Building Geometry & Topographic steps.

Generate the Engineering Report from your inputs and results, then Print / Download it (HTML, Excel or CSV), or use ☁ Save in the header. Run Calculate on the previous step first.