Low-slope edge-metal pieces can be joined in a number of
ways—overlap, cover plate, concealed plate. The NRCA
Roofing and Waterproofing Manual, Fifth Edition, provides
several alternative joinery options for a number of edge-metal
shapes in its Construction Details section.
Detail SM-5, "'A' type edge metal with overlap," provides one of
two methods to join two pieces of metal when using a gravel stop
edge for low-slope roofing; the other method is a cover plate
detail. A concealed plate joinery detail for the "A"-type edge
metal is not provided because of the difficulty of nesting the
Edge metal is the first line of defense against uplift
resistance. To provide adequate uplift resistance, a proper
fastening schedule, as shown in the figure, is needed to adequately
secure a flange to a wood nailer. (This assumes the wood nailer is
secured properly to the top of the wall.) Proper fastening of a
cleat and proper engagement of edge metal to a cleat also are
critical elements for adequate uplift resistance. BUR-MB-Table 1
"Guide for sheet metal fascia edges for built-up and modified
bitumen membranes" states the cleat is to be fastened at about 6
inches (150 mm) on center.
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