Section 6.1.10

Horizontal Cavity Tray to Flat /
Lean-to Roof

Flashing above flat roofs and bay roofs are required to link in with a cavity tray. Raised cavity trays to allow for the installation of lead work above flat roof and bay windows can leave an opening vulnerable to moisture ingress. Driving rain can force moisture beyond the cavity trays and in to the property.

  • Vertical DPC extends from lintel.

  • Additional ties added either side of Vertical DPC as per movement joint.

  • Vertical DPC joins with the main cavity tray.

  • Horizontal cavity tray location in relation to flashing.

  • Installed on a bed of mortar with 25mm raked out from face while green.

  • Use proprietary trays as per the design.

  • Mortar raked out 25mm to allow for the installation of the flashing.

  • Weep holes set no more than 450mm apart.

  • Vertical DPC Returned under the horizontal cavity tray.