ASCE 7-22 · ROOF UPLIFT · ZONES 1 · 2 · 3
Roof Wind Uplift Calculator
Wind lifts a roof harder than it pushes on any wall — and hardest at the corners, where suction can run several times the field of the roof. This calculator returns the net ASCE 7-22 uplift pressure in psf, by zone, for gable, hip, flat, and monoslope roofs — from a ZIP code, with the Florida HVHZ value where it governs.
No signup. Enter a ZIP → get the ASCE 7-22 design wind speed → get the net roof uplift pressure by zone. Every coefficient cited to its section.
HOW ROOF UPLIFT IS CALCULATED
Suction, by zone
Roof uplift is the net outward pressure trying to peel the roof off the building. Under ASCE 7-22 it starts from the velocity pressure at the mean roof height, then applies a roof coefficient that is strongly negative — most negative at the corners.
STEP 1 · VELOCITY PRESSURE AT ROOF HEIGHT
qh = 0.00256 × Kh × Kzt × Kd × Ke × V²
Evaluated at the mean roof height h, in psf. V is the mapped ASCE 7-22 basic wind speed for the site.
STEP 2 · NET UPLIFT PRESSURE
p = qh (GCp − GCpi)
The roof external coefficient GCp is negative — outward suction — and the internal coefficient is taken at the sign that worsens it. A negative result is uplift.
qh
Velocity pressure at the mean roof height — the starting point for every roof pressure.
GCp
Roof external coefficient — negative (suction), and largest in magnitude at edges and corners.
GCpi
Internal coefficient — enclosed ±0.18, partially enclosed ±0.55; taken at the worst sign.
Eff. area
Effective wind area — smaller areas (a fastener, a clip) read a larger uplift coefficient.
Zone
Field (1), edge (2), or corner (3) — the coefficient grows from field to corner.
The calculator reads GCp off the ASCE 7-22 roof figures for each zone and effective wind area — you get the psf value, not a chart to squint at. See the method in the roof wind uplift guide.
ROOF PRESSURE ZONES
Corners lift first
A roof is not loaded evenly. Wind separates at the edges and corners and spins into vortices there, so the suction — and the uplift — is far higher at the perimeter than in the middle. ASCE 7-22 captures this with three zones.
Zone 1 — field
The interior of the roof, away from every edge. Lowest uplift — but still net outward on most roofs.
LOWESTZone 2 — edge
The perimeter strip along each eave and ridge. Uplift steps up as the flow separates over the edge.
HIGHERZone 3 — corner
The corners, where two edges meet and the vortices are strongest. The governing uplift for fasteners and edge metal.
HIGHESTThe calculator returns the psf uplift for each zone at your effective wind area — no figure-reading. Want the coefficient tables? See the roof wind uplift guide.
BY ROOF SHAPE
Every roof, its own uplift
Roof shape decides where the wind separates and how hard it pulls. The calculator applies the right ASCE 7-22 figure for the roof you enter.
Gable & hip
Uplift varies with roof pitch; low slopes and the windward eave and ridge see the sharpest suction.
PITCHEDFlat & low-slope
Nearly all uplift, all the time — corners and edges govern the membrane, ballast, and fasteners.
MEMBRANEMonoslope & overhangs
Single-slope roofs and any overhang take extra uplift from wind driving up under the eave.
OVERHANGFLORIDA HIGH-VELOCITY HURRICANE ZONE
Where roof uplift is highest in the nation
The HVHZ — Miami-Dade and Broward under the Florida Building Code — carries design speeds around 170–175 mph. Because suction scales with the square of the speed, roof uplift there is the most severe in the country: it governs the deck attachment, the fastener schedule, and the edge-metal fastening. The calculator applies the HVHZ speed and county overrides on its own, so the corner and edge uplift match the jurisdiction rather than a generic estimate.
RUN THE NUMBERS
Your roof uplift, in about a minute
Skip the figures. Enter a ZIP and the roof details — the calculator pulls the ASCE 7-22 design wind speed, reads GCp for the roof zone and effective wind area, and returns the net uplift in psf, field to corner. Free for a single component; full projects and an Engineering Report are on the calculators.
Need the whole building, roofs, or specialty structures? See all calculators & pricing →
COMMON QUESTIONS
Roof wind uplift, answered
How is roof wind uplift calculated?
Under ASCE 7-22, the velocity pressure at the mean roof height qh = 0.00256 KhKztKdKeV² first turns the design speed into a psf value at the eave-to-ridge height. The net uplift is then p = qh(GCp−GCpi), with the roof coefficient GCp negative — pure outward suction.
Why is roof uplift highest at the corners?
Wind separating over the roof edges rolls into vortices, and those vortices are strongest where two edges meet — the corners (Zone 3). The suction there can be several times the field of the roof, which is why corner fasteners and edge metal are spaced tightest.
Which roof shapes does the calculator cover?
Gable, hip, flat and low-slope, and monoslope roofs, including overhangs. It applies the correct ASCE 7-22 roof figure and zone layout for the shape and slope you enter, then returns the uplift by zone.
Is roof uplift a C&C or an MWFRS load?
Both, for different parts. Components & cladding uplift sizes the roof deck, panels, and fasteners; the MWFRS roof pressure loads the overall structural system and the roof diaphragm. See the C&C guide and MWFRS guide.
KEEP READING
Related wind load guides
Components & Cladding
Zones, GCp coefficients, effective wind area, and a worked example.
C&CMWFRS Wind Pressure
Whole-building pressures, base shear, and overturning.
MWFRSWind Speed by ZIP
Find the ASCE 7-22 design wind speed — the V that starts every pressure.
V INPUTRoof Uplift Guide
The theory behind roof suction — zones, GCp, and worked examples.
GUIDEWind Load Pressure
The full picture: velocity pressure, C&C, and MWFRS, all in psf.
HUBFlorida HVHZ
Miami-Dade & Broward: the highest design pressures in the country.
HVHZ