How do I square up and level a roof curb on a pitched roof?
3rd YearRoof Work & CurbsYELLOW · Check First
Find the high point of the roof steel or deck where the curb will sit.
Plain-English answer
Find the high point of the roof steel or deck where the curb will sit.
Measure diagonally from corner to corner of the curb in an "X" pattern to verify the curb frame itself is perfectly square (the two diagonal numbers must match exactly).
Level the curb along its top flange using shims or by adjusting the integrated pitched wrapper sides.
The curb top must be dead level even if the roof is sloped, otherwise the Rooftop Unit (RTU) compressor will pool oil incorrectly and fail prematurely.
Field checklist
- Find the high point of the roof steel or deck where the curb will sit.
- Measure diagonally from corner to corner of the curb in an "X" pattern to verify the curb frame itself is perfectly square (the two diagonal numbers must match exactly).
- Level the curb along its top flange using shims or by adjusting the integrated pitched wrapper sides.
- The curb top must be dead level even if the roof is sloped, otherwise the Rooftop Unit (RTU) compressor will pool oil incorrectly and fail prematurely.
Ask Foreman
Hey boss, I’m checking roof work & curbs: How do I square up and level a roof curb on a pitched roof? I found the likely issue and want to verify the next step before I lock it in. Do you want me to adjust it now or check the drawing/detail first?
Verify before acting
Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.