Pitched roofs

7.2.13Dormer construction

Dormer constructions shall be of adequate structural stability.

For dormer roofs:

  • construction should be in accordance with the design
  • cheek studs should be supported by either a double rafter or a double floor joist
  • where cheek frames do not extend to floor level, two fixed rafters should be used to provide the necessary support
  • trimming members should be large enough to support additional loads from the main roof members, dormer framing and cladding
  • a suitable lintel should be provided over the opening
  • lintels should be structurally independent from the window frame.

Proprietary dormers

Proprietary dormers should be:

  • in accordance with Technical Requirement R3
  • suitably durable
  • installed in accordance with certification requirements