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Roof Structure

Structural Deterioration And Damage

Problem: Sagging roof support structure around openings.

Cause: Inadequate framing around openings in roof trusses and rafters.

Solutions: Frame openings to allow for proper transferring of loads.

  • Whenever a rafter must be cut to provide space for a skylight, frame the roof structure properly to allow for adequate load transfer.
  • When a rafter is cut, double rafters should be installed on each side of the skylight area. Place double headers between the double rafters and securely fasten cut rafters into the double headers. Joist hangers can be used to connect cut rafters to the double headers. The headers will transfer the loads from the cut rafters to the adjoining rafters as shown in Figure 18.

Correct Method of Creating A Roof Opening

Figure 18 - Correct Method of Creating A Roof Opening.
  • Trusses should not be notched or cut without the truss manufacturer's shop drawings and instructions to ensure that loads are sufficiently transferred.

Additional information on skylight installation.

Additional information on roofs and roofing