Roof Slope Guide

Why Convert Units?

In construction, different trades speak different languages regarding slope. Miscommunication here is a common cause of field errors.

• Architects & Framers: Use Pitch (Rise over 12). E.g., "4:12" or "1/4 on 12".
• Structural Engineers: Often use Degrees for trigonometry calculations in software like RISA or Tekla.
• Site/Civil Engineers: Use Percentage for grading and drainage (e.g., "2% slope").

Common Steel Pitches

Pre-Engineered Metal Buildings (PEMB) typically use lower slopes to save material:

• 0.5 : 12 to 1 : 12: Standard for screw-down metal roofs (PBR panels).
• 0.25 : 12: Ultra-low slope for Standing Seam roofs (requires clips to allow expansion).
• 4 : 12: Common for "Agricultural" style buildings or residential aesthetic.