Help · Calculators
How to use the SkyCanvass roofing calculators.
Nine calculators that take field measurements and return material orders + waste factors. Each pulls the relevant code citation when an address is associated.
Drip edge
Linear feet input, calculates pieces + waste factor for D-style or L-style profiles.
Ice & water shield
Eave length + pitch + wall-line offset, returns square feet of self-adhered membrane.
Pipe boots
Penetration count, returns boot count + flashing material per IRC R903.4.
Ridge cap
Ridge + hip linear feet, returns bundles or linear feet of pre-cut hip-and-ridge.
Starter strip
Eave + rake linear feet, returns starter strip footage with manufacturer waste.
Step flashing
Sidewall length, returns step count + counter flashing footage per R905.2.8.3.
Underlayment
Roof area + slope, returns squares of #15 felt or synthetic with overlap factor.
Valley metal
Valley length + valley type (open / closed-cut), returns metal LF + waste.
Ventilation
Attic floor area, returns required NFA + product mix to satisfy 1:300 with balanced flow.
Inputs and waste factors
Every calculator takes field measurements (linear feet, square feet, count) and returns a material order with a waste factor applied. Default waste factors come from the manufacturer cut sheets and NRCA / ARMA field-typical values:
- Drip edge / starter strip / step flashing: 5% (factory-finished metal).
- Ice & water shield / underlayment: 10% (overlap + waste at corners).
- Ridge cap (pre-cut): 5%; field-cut from 3-tab: 10-12%.
- Valley metal: 8% (cut + bend + lap).
You can override the default waste factor on any calc — it's a percentage input on every tool. The override saves to the address profile so your defaults apply across calculators for that property.
Code citations on outputs
When you run a calculator with an address attached, the output PDF includes the relevant IRC section and any state amendment for that property. The drip-edge calculator includes R905.2.8.5; the IWS calculator includes R905.1.2; the ventilation calculator includes R806. The citation is verbatim, so a reviewer can see the basis without leaving the document.
Interactive calculators ship in the workspace
Free to start — property lookups, state code access, the hail map, and your first storm report on us. No credit card required to look up an address.