CEMP-ET
TI 809-53
01 May 1999
(a) If installing a new metal roof over an existing metal roof, design should indicate method
of anchoring the new system.
(b) Verify compatibility of metals especially if existing structures use copper copings, eaves
or flashings.
(c) Field testing on the actual roof should confirm pull-out strength of the fasteners planned
for the new roof system.
(d) Penetrations must be extended through new metal panel roof. Use oversize holes with
flexible boots to accommodate movement of panels. Penetrations must pass through the flat portion of
panel, not the standing seam.
(5) Nonmetal Checklist.
(a) Loose-laid Ballasted Single Ply Checklist
1/ Check for compatibility problems.
2/ Establish ballast retention methods at eaves, drains and scuppers.
3/ Determine quantity and size of ballast required for corners, perimeters and field.
4/ Verify that roof edge height conforms to ANSI/SPRI RP-4 recommendations.
5/ Verify that river washed rounded ballast is available. If crushed stone is used, is
stone-mat used for membrane protection?
(b) Bituminous (BUR and MB) Checklist:
1/ If bituminous adhesives will be used verify that the existing roof surface is free of dirt
and loose gravel.
2/ If mechanical fasteners will be used to secure re-cover insulation verify that their
length will be adequate. This is especially critical when tapered insulation is used.
(c) Sprayed Polyurethane Foam (SPF) Checklist:
1/ If SPF will be applied directly to the surface of an existing gravel surfaced BUR the
surface should be thoroughly cleaned with high pressure/low volume water jets and vacuumed, then
allowed to dry.
2/ Repair splits to existing BUR, and remove blisters, buckles, wrinkles, and fishmouths.
Use hot mopped or torch-applied repairs. Do not use asphalt mastics for repairs.
3/ Take precautions to avoid overspray of surrounding buildings, automobiles, shrubs,
and so forth.
4/ Coat all exposed foam within four hours.
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