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Roof Structure

Water Leakage

Problem: Rotting of structural members and sheathing materials

Cause: Water leakage around flashings.

When roofing materials are damaged or inadequately flashed, water can leak through, wetting the sheathing and structural members. Constant wetting will result in decay of the sheathing and the structural members.

Solutions: Roof flashings must be installed properly.

  • Provide flashing and, where applicable, counterflashing at all intersections between roofs, walls and chimneys. This will accommodate differential movement between surfaces and prevent the entry of water as shown in Figure 23.

Flashings Required At Roof Penetrations

Figure 23 - Flashings Required At All Roof Penetrations
  • Follow manufacturers' flashing details for roof vents. Use preformed neoprene flashing for vent pipes.
  • Flashing should be durable, weather-resistant and maintenance-free.
  • Replace or repair damaged materials before you install flashings.

Additional information on roofs and roofing