Snow Load Calculator

How It Works

Snow weight varies enormously by type. Fresh powder weighs only 5 lbs per cubic foot, but wet heavy snow weighs 20 lbs and ice is 57 lbs. A foot of wet snow on a 2,000 sq ft roof weighs 40,000 lbs (20 tons). Steeper roofs shed snow naturally — pitches over 6/12 reduce snow accumulation significantly. Watch for drifting against walls and around dormers, which can create loads 2-3x the uniform depth. Warning signs of overloading: sagging ceiling or roof ridgeline, cracking sounds, doors and windows sticking, and visible bowing of rafters. Remove snow with a roof rake from the ground — never go on the roof during heavy snow.