Template:All systems - ROOF DECKS

1 Concrete

Concrete decks, curbs and equipment pads must be clean, dry, and smooth prior to commencement of roofing.

Poured concrete or lightweight concrete decks are not to be roofed for a minimum of 28 days after pouring unless expressly instructed in writing by the Project Structural Engineer.

2 Wood

All wood decks shall be properly fastened to B.C.Building Code requirements. With the exception of standard insulated roof systems, all knots or cracks shall be covered with metal prior to acceptance of deck surface.This work is to be done by others. Non-veneer (O.S.B. or wafer board) panels are acceptable sheathing for decks with low-slope roofing applications, provided the roofing membrane is not fully adhered directly to the panels. The minimum plywood or non-veneer (O.S.B or wafer board) deck thickness for low-slope roofing (i.e., membrane roofing) shall be a minimum 12.7 mm (1/2")and as indicated in the applicable Building Code.

Differential edge movements or deflection in excess of1/360 of the span in plywood or non-veneer decks in low slope roofing must be prevented by:

• solid blocking under non-supported edges, and /or
• use of tongue-and-groove plywood with non-grooved edges supported by joists or solid blocking, and / or
• when rigid insulation is over the deck, properly sized and installed H-clips must be used on the unsupported edges.

3 Special Circumstances: Electrical Conduit

Conduit, EMT, cable and/or piping applied on the top of roof deck surfaces shall not be acceptable on new construction projects. If conduit is present on decks in re-roofing projects, the deck must be made smooth and even to the satisfaction of the accepted roof inspection firm. The upper layer of insulation must cover the conduit, EMT, cable and/or piping. Detailed as-built drawings should be made to prevent conduit damage and safety risks to roofers, should the roof require replacement at a future date.