Ballast Mount Calculator

Calculate ballast weight needed to resist wind uplift forces on non-penetrating flat-roof PV mounts.

Input Parameters

Results

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Wind Uplift Pressure
psf
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Uplift Force per Module
lbs
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Ballast Weight Needed
lbs
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Ballast per Area
psf
Note: Ballast-mounted systems avoid roof penetrations but add significant dead load (typically 3-8 psf). Verify roof can support additional ballast weight per IBC.

Reference

qz = 0.00256 × Kz × Kd × V² (ASCE 7) Wind Pressure = qz × GCp × Lift_coeff Uplift Force = Wind Pressure × Module Area Ballast = (Uplift − Module Wt) × SF / μ SF = 1.5, μ = friction coefficient