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Wind Uplift on Roof

ASCE 7 C&C · qz · GCp · Net Uplift · Fastener Force

When to use: Estimate wind uplift pressure on roof components and cladding per ASCE 7-16 Chapter 30. Compute the velocity pressure qz, apply the roof-zone external pressure coefficient GCp combined with internal pressure GCpi, and size the net uplift and required fastener force. Corner (Zone 3) and edge (Zone 2) regions govern fastener attachment of decking, membrane, and panels.

Wind & Roof Parameters
mph
enclosed ±0.18
per fastener
ft²
Key Formulas
qz = 0.00256·Kz·Kzt·Kd·V²
p = qh·(GCp − GCpi)
F = |p|·A_trib
Enclosed bldg: GCpi = ±0.18
Negative GCp = uplift
Net Uplift Pressure
84.0
psf
Results
Velocity Pressure qz28.2 psf
External GCp-2.80
Internal GCpi0.18
Net Pressure p-84.0 psf
Uplift |p|84.0 psf
Tributary Area4.0 ft²
Force per Fastener F336 lb
References
ASCE 7-16 §26.10 — velocity pressure
ASCE 7-16 §30 — Components & Cladding
ASCE 7-16 Fig 30.3 — GCp roof zones