In many U.S. homes, roof trusses are spaced 24 inches on center, meaning the center of one truss is 24 inches from the center of the next. Some roofs use 16-inch spacing, and other layouts are possible when an engineer designs them. The right spacing depends on the trusses, roof loads, sheathing, roofing materials, and local building requirements—not on a universal rule. Knowing how truss spacing works helps homeowners understand plans, estimate framing needs, and avoid unsafe changes.
For a specific roof, useful documents include the permit-approved framing plan, truss placement diagram, individual truss design drawings, sheathing product markings, and installation instructions. The Structural Building Components Association and Truss Plate Institute provide industry resources related to structural building components and truss safety. The local building department can confirm which code edition and amendments apply.
The practical rule is simple: treat 24 inches O.C. as a common layout, not a universal standard. Use the spacing shown in the approved plans, verify that sheathing and roofing products are compatible, and obtain professional approval before changing a truss layout or modifying an individual truss.