Grain bin roofs have a 30° slope.
Bins 42′ (12.80 m) diameter and smaller use single-stage self-supporting roof sheets. Bins 48′ (14.63 m) diameter and larger are designed with complete structural systems consisting of “C” shaped rafters and purlins (raftered roof). Standard non-raftered roofs are designed for a 2 psf dead load and 20 psf live/snow load. Roof designs and pricing for live/snow loads greater than 20 psf are available as an upgrade.
Standard raftered roofs are designed for 6 psf dead load and 25 psf live/snow load. Live/snow loads larger than 25 psf will require a special design.