SBS 11.3.2.2-1 Cast Iron Drains

RoofStar Guarantee Standards are blue-linked

SBS Details

(1) Supporting Deck Overlay: If required by design authority.
(2) Air or Vapour Control Layers: If required by design authority.
(3) Insulation: Mechanically fastened. See available insulation products in the Accepted Materials section of this Manual.
(4) Insulation Overlay: Asphalt adhered or mechanically fastened. Two layers required over heat-sensitive insulation.
(5) Primary Membrane and Membrane Protection
(6) Mastic: As approved by manufacturer.
(7) Base Membrane Flashing: As approved by membrane manufacturer (See (C) below).

(A) Acceptable Supporting Deck Structure
(B) Roof Drain Assembly
(C) Lead Flashing: Minimum 15 kg / m² (3 lb / ft²) weight lead sheet; flange extending minimum 25 mm (1") into bowl to 150 mm (6") beyond perimeter of drain; embed in mastic (6) and prime top surface where required by manufacturer or minimum 1 m x 1 m (39" x 39") 3 mm thick modified bituminous base sheet; to be supplied by trade supplying roof drain. For optional installation methods that use a membrane flashing in place of lead, see 11.3.2.2 Cast-iron Roof Drains.

NOTE: Refer to RoofStar Guarantee Standards for additional requirements.

Leader size is determined by using the calculation found in the BC Building Code at Appendix P.7.4.10 and Section 7.4.10.11 (Section 7.4.10.10 for gutters)(current edition) in conjunction with the 15-minute rainfall value from the National Building Code, Appendix C.