Problem: Sagging Roof Sheathing.
Cause: Sheathing materials too thin to support concrete or clay tile roofing.
Most building codes for panel type sheathing require a thickness of 3/8 inch (9.5 mm) when supported spacing is 24 inches (600 mm). This thickness will support design dead and live loads but may allow deflections which cause a poor appearance.
Solutions: Reduce spacing of trusses and rafters.
- To reduce deflection of roof sheathing, you may decrease the spacing of roof supports from 24 inches (600 mm) to 16 inches ( 400 mm) o.c.
Solutions: Increase thickness of roof sheathing.
- You may also reduce deflection by increasing the sheathing thickness above minimum building code requirements as shown in Table 1.
Additional information on roofs and roofing