Calculator Help Guide

Help guide

Calculator help guide: measure, plan, and order

Use the jump bar to open the exact help you need without scrolling. This guide matches the calculator and the advanced estimator workflow.

Tip: Use the jump bar to open the exact section you need without scrolling.
Planning support for the calculator and estimator workflow.
How to measure
Calculator and estimator use the same two key dimensions:
  • Width = span across the building (roof) or total wall length (wall mode)
  • Run = slope length from eave to ridge (roof) or wall height (wall mode)
If you only know pitch and span, use the estimator pitch tool to calculate run.
How to calculate your roof run (slope length)

If you do not know the exact panel length, use the pitch tool to calculate run from your span and roof pitch.

  1. Enter your building span
    • Gable roofs (2 slopes): use half the total building width (panels run from ridge to one eave).
    • Shed or lean-to (1 slope): use the full building width.
  2. Choose your pitch
    Example: 4/12 means the roof rises 4 inches for every 12 inches of horizontal travel.
  3. Automatic overhang allowance
    The tool automatically adds a 1.5 inch overhang so panels extend past the eave for proper drainage.
Pro tips:
  • Check your eaves: if you want more than 1.5 inches of overhang, add a little to your run after calculating.
  • Measure twice: confirm on-site before ordering—framing can vary from plans.
Gable roof measurement (most common)
Width is the span. Run is the slope length.
Front or end view
RIDGE WIDTH (SPAN) RUN (SLOPE)
Side or gutter view
RIDGE CAP EAVE LINE WIDTH REFERENCE
Run is not the flat building length. Run is the sloped panel length you order from eave to ridge.
Shed or lean-to roof measurement
One slope. Run still means slope length.
Front or end view
WIDTH (SPAN) RUN (SLOPE)
Side view (high and low eave)
HIGH EAVE LOW EAVE
Shed roofs still order panels by run (slope length). Width is the span across the roof.
Wall or siding measurement
Width becomes total wall length. Run becomes wall height.
Total wall length
TOTAL WALL LENGTH
Wall height
HEIGHT
Enter the combined wall length if you are doing multiple walls. For height, it is common to order the next available length and trim to fit.
Fast check before you calculate
  • If your run or height is over 14 ft, plan for stacked panels and a minimum 6 inch end lap.
  • Add a waste factor (typical planning range 5 to 15 percent).
How to plan
Planning is about coverage and overlap. The calculator and estimator handle the math, but you should understand the rules so your order matches real installation.
Coverage quick reference
  • 36 inch Pro Rib: 36 inch coverage (3 ft)
  • 29 gauge corrugated roof: 21.5 inch coverage (two rib overlap)
  • 29 gauge corrugated wall: 24 inch coverage (one rib overlap)
  • Polycarbonate corrugated: 24 inch coverage (matches corrugated physical width)
If you switch between roof and wall mode on corrugated, coverage changes because overlap changes.
Waste factor guidance
  • 5% simple runs, few cuts
  • 10% typical DIY planning
  • 15% complex roofs, lots of penetrations, more trimming
Waste helps you avoid coming up short on matching panels and trim.
Corrugated and polycarbonate overlap (rib overlaps)
These profiles explain why coverage changes between corrugated roof versus wall, and how poly panels lap.
Corrugated metal roof (2 rib overlap)
Corrugated metal roof overlap profile showing two-rib sidelap

Roof overlap is larger for better water control. This is why corrugated roof coverage is reduced (commonly ~21.5").

Corrugated metal wall (1 rib overlap)
Corrugated metal wall overlap profile showing one-rib sidelap

Wall overlap is smaller to maximize coverage (commonly ~24"). Use wall-mode overlap rules for siding projects.

Polycarbonate corrugated (1 rib overlap)
Polycarbonate corrugated overlap profile showing one-rib overlap

Polycarbonate typically overlaps 1 rib. Allow for thermal movement and follow fastener and washer guidelines for watertight installs.

Key idea: overlap is what changes coverage. Roof-mode corrugated uses a larger sidelap for better water control. Wall-mode corrugated uses a smaller overlap for more coverage per panel. Polycarbonate typically overlaps one rib to match corrugated layout.
Want this section upgraded?

We can replace these visuals with full manufacturer overlap sheets, add fastener patterns, and include profile-specific notes.

Overlap visuals (so the numbers make sense)
Pro Rib uses the real overlap diagram. End lap shows stacked panels for long runs.
Pro Rib overlap (anti siphon)
36 inch Pro Rib correct sidelap and anti siphon detail
End lap for long runs (stacking)
LOWER (B ft) UPPER (A ft) MINIMUM 6" OVERLAP
If your run is over 14 ft, the estimator will recommend a stacked plan. Use a minimum 6 inch end lap. Longer overlap is acceptable.
Skylight note (polycarbonate in corrugated metal roofs)
  • Skylights are for 29 gauge corrugated roof projects only
  • Not for Pro Rib, not for wall projects, not for full polycarbonate roofs
How to order
Order in the same order you install:
  1. Confirm project type and profile
  2. Confirm panel length plan
  3. Add panels, then trim, then screws
  4. Save or print your plan for pickup or delivery scheduling
What to take from the calculator
  • Panel length plan (what lengths and quantities)
  • Trim totals (roof mode)
  • Screw estimate (boxes rounded up)
  • Waste factor you selected
What to take from the estimator
  • Pitch tool for run calculations
  • Auto pricing presets (if enabled)
  • Printable quote sheet for email or planning
Tip: If you are ordering multiple buildings or multiple roof sections, do one section at a time so your panel plan stays clean.