Roof calculators, all in one place
Snow load, by roof type
The full ASCE 7-22 engine, pre-set for each roof type.
Cs = 1.0 (no slope shedding); watch the minimum load and rain-on-snow surcharge.
Slope factor Cs reduces the load; gable roofs also need the unbalanced case (§7.6.1).
Slippery surface → Cs sheds sooner; unheated buildings use Ct = 1.2.
Open / unheated → Ct = 1.2; check the kit's rated load against this number.
Single slope → one Cs; check windward drift at the high side.
Use the shallow upper slope for the balanced load; check unbalanced snow.
Heated glazing → Ct = 0.85; an unheated hoop house does NOT get the reduction.
Shows the full Pg → Pf → Ps conversion with every factor exposed.
Roof geometry & framing
Pitch, rafters, trusses and joist spans; the layout math before you cut lumber.
Converts rise-per-12 to angle, slope % and the rafter-length (roof) factor.
Converts run + pitch + overhang into actual rafter length and a stock board length.
Truss count from building length and on-center spacing, with gable ends.
Bending- and deflection-limited span from real mechanics, with editable Fb / E.
Insulation & HVAC
R-value and a quick cooling-load planning estimate for the building envelope.
Cost
A national-average planning range before you call a contractor.