Which statement is not true about light weight panelized roof configurations?

• A. Beams: 12'-40' Apart
• B. Purlins: 8' on Center
• C. Ceiling Joists: 24" on Center
• D. Beams: 8' on Center

Answer: (D)

Light weight panelized roof configurations rely on primary beams that span long distances, with supporting elements spaced to carry the load efficiently. In these systems, beams are typically spaced widely—roughly 12 to 40 feet apart—so the roof deck or sheathing and purlins can span between them. The purlins, which run perpendicular to the beams, are usually placed about 8 feet on center to provide intermediate support for the roof material. Ceiling joists, which help tie the structure together and give a base for the interior ceiling, are commonly spaced around 24 inches on center.

The statement that is not true is the one claiming beams are spaced at 8 feet on center. Such close spacing for beams would imply a much heavier and more costly frame and does not reflect how light weight panelized roofs are typically built. The other spacing values align with the standard pattern: wide beam spacing, intermediate purlin spacing, and standard ceiling joist spacing.