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The design wind uplift pressure acting on the array, from your wind load analysis.
This is the net uplift pressure the racking system must resist, typically taken from a project-specific wind load calculation or the racking manufacturer's engineering documentation.
The total plan area covered by the solar panel array.
Use the total footprint area of the ballasted array being checked — this is the tributary area the uplift pressure acts over.
A multiplier applied to the calculated uplift force to account for uncertainty in wind loading and ballast performance.
A safety factor above 1.0 provides margin against wind load uncertainty, ballast friction/interlock assumptions, and non-uniform uplift distribution across the array.
Required ballast mass
20,300 lb
This is a simplified whole-array tributary calculation — actual ballast distribution requires a location-specific wind uplift analysis per ASCE 7 (uplift varies significantly by roof zone: field, perimeter, and corner), typically performed by the racking manufacturer's engineer for the final layout.
- Total wind uplift force
- 13,533.76 lbf
They open the calculator with your figures already in it
Solar Panel Roof Mount Wind Uplift Ballast Calculator: 20,294 lb — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Uplift force = wind uplift pressure × array area; required ballast mass = uplift force ÷ gravitational acceleration × a safety factor, the standard method for sizing ballast counterweight against calculated wind uplift
Inputs used
- Design Wind Uplift Pressure
- 25.06 psf
- Solar Array Area
- 540 sq ft
- Safety Factor
- 1.5
Intermediate steps
- Total wind uplift force
- 13,533.76 lbf
Confidence note: This is a simplified whole-array tributary calculation — actual ballast distribution requires a location-specific wind uplift analysis per ASCE 7 (uplift varies significantly by roof zone: field, perimeter, and corner), typically performed by the racking manufacturer's engineer for the final layout.
What this calculation does not cover
- The uplift pressure is applied uniformly across the whole array footprint and the answer comes back as one total mass. It carries no distribution: corner and perimeter modules see far higher uplift than modules in the field of the roof, so spreading this total evenly leaves the edges light and the middle heavy.
- No credit is taken for the weight of the modules, rails and racking, which already resist uplift. A real ballast schedule subtracts that self-weight before sizing blocks, so this figure is the mass required as if the array weighed nothing rather than the mass of concrete to add on top of the hardware.
- Only vertical lift-off is checked. Wind also drives the array sideways and can rotate a row about its downwind edge, and both depend on friction between the ballast pads and the roof surface and on how well the array is tied together as one block — none of which is entered here.
- The roof structure is not checked. Ballast is permanent dead load concentrated under the trays, and nothing here confirms the deck can carry it alongside snow and the array's own weight, or that the point loads stay within the deck's capacity.
- The uplift pressure is an input, not a result — nothing derives it from wind speed, exposure, building height, parapet, roof zone or module tilt, and the answer scales directly with whatever figure you type. The safety factor is a plain multiplier, not a code load combination, so this is a sizing check and not the stamped ballast design a ballasted array normally requires.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-02 · in the site-wide review of 2026-09-06 · v1.1.1
Regulatory standards & verification citations1
- Uplift force = wind uplift pressure × array area; required ballast mass = uplift force ÷ gravitational acceleration × a safety factor, the standard method for sizing ballast counterweight against calculated wind uplift
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