f) Limit plywood to 5/8 inch (16 millimeters) minimum
thickness, smooth-surfaced exterior grade, with edge support
limiting differential deflection of adjacent panels to 1/8 inch
(3 millimeters) at panel edges and 1/16 inch (2 millimeters) at
g) Do not specify fluid-applied synthetic membranes
when substrate joint movement is anticipated;
Consider repairability in case of future damage.
i) Roof deck structural capacity: For loose-laid,
ballasted systems, design for additional 10 to 25 psf (0.0005 to
0.0012 Pascal) dead-load capacity for ballast and/or concrete
j) If there is waste spillage or exhaust onto roof
surface, determine the nature of waste material. Periodic roof
wash-down may be required; or other special membrane maintenance;
Check compatibility of adhesives, films and
l) Do not permit "torching" of modified bitumen sheets
on buildings with combustible substrate components.
Applicable Details. Refer to SMACNA Architectural
Sheet Metal Manual or manufacturers' information.
Single-Ply Membrane Standards. Where applicable,
standards to be used for single-ply membrane materials are
promulgated by the Rubber Manufacturers Association (RMA),
American Society of Testing and Materials (ASTM), and the
Canadian General Standards Board (CGSB).