When the roof run is entered as a horizontal dimension, the approximate sloping sheet length is calculated from the roof angle.
Sloping Length = Horizontal Run ÷ cos(Roof Angle)
For a two-sided pitched roof, the calculated requirement is applied to both roof sides.
Important Limitations
This is a preliminary metal roofing sheet quantity estimator.
It assumes a simple rectangular roof area.
It does not calculate roof framing or purlin requirements.
It does not determine the correct roofing profile.
It does not determine manufacturer-specific lap requirements.
It does not calculate ridge, valley, flashing or penetration requirements.
It does not optimize sheet cutting or nesting.
Complex roofs with hips, valleys, dormers and irregular geometry require separate takeoffs.
Actual side-lap and end-lap requirements depend on the roofing profile, installation method, roof pitch and manufacturer.
Use this result for preliminary material estimating only. Confirm actual sheet coverage, side laps, end laps, fastening details and installation requirements against the selected roofing system and manufacturer's specifications.
Frequently Asked Questions
What does the Metal Roof Sheet Overlap Estimator calculate?
It estimates the number of roofing sheets needed after accounting for effective sheet coverage, side laps, end laps, roof slope and waste.
Does it account for side laps?
Yes. The side-lap value is deducted from the overall sheet width to calculate effective coverage.
Does it account for end laps?
Yes. The end-lap value is deducted from sheet length when calculating the number of rows required along the roof slope.
Does it calculate roof slope length?
Yes. Enter the horizontal roof run and slope angle to estimate the sloping sheet length.
Can it calculate a two-sided pitched roof?
Yes. Select two roof sides and the calculator applies the sheet requirement to both sides.
Does it calculate roofing accessories?
No. Ridge caps, valleys, flashings, screws and other accessories should be estimated separately.