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.

Switch Exposure right here to see how the design pressures change — no need to step back. This is the same Exposure as the Wind Parameters step: changing it here updates it there too, and it's the value used in the live pressures, the Engineering Report, and the saved project. Exposure is the terrain roughness around the building (ASCE 7-22 §26.7) — set the one that matches the site, not the lowest number.

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.