SECTION 07620
SHEET METAL FLASHING AND TRIM
PART 1
GENERAL
1.01 SECTION INCLUDES
A.
Counterflashings at roof curb mounted equipment.
B.
Cap flashings.
1.02 RELATED SECTIONS
A.
Section 06100 - Rough Carpentry.
B.
Section 07532 - Single Ply Roofing.
C.
Section 07900 - Joint Sealers.
1.03 REFERENCES
A.
ASTM A525 - Steel Sheet, Zinc Coated, (Galvanized) by the Hot-Dip Process.
B.
ASTM B32 - Solder Metal.
C.
ASTM D226 - Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing.
D.
ASTM D4586 - Asphalt Roof Cement, Asbestos-Free.
E.
Water Cut-off Mastic - provided by membrane roofing manufacturer. (Section 07532)
F.
FS O-F-506 - Flux, Soldering, Paste and Liquid.
G.
NRCA (National Roofing Contractors Association) - Roofing Manual.
H.
SMACNA - Architectural Sheet Metal Manual.
1.04 SUBMITTALS
A.
Submit under provisions of Section 01300.
B.
Shop Drawings: Indicate material profile, jointing pattern, jointing details, fastening
methods, flashings, terminations, and installation details.
1.05 QUALITY ASSURANCE
A.
Perform work in accordance with SMACNA and NRCA standard details and
requirements.
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B.
Maintain one copy of the specifications and approved shop drawings on site.
1.06 QUALIFICATIONS
A.
Fabricator and Installer: Company specializing in sheet metal flashing work with 5
years documented experience.
1.07 DELIVERY, STORAGE, AND HANDLING
A.
Deliver, store, protect and handle products to site under provisions of Section 01600.
B.
Stack preformed material to prevent twisting, bending, or abrasion, and to provide
ventilation. Slope metal sheets to ensure drainage. Secure to prevent damage to
metal and to roof during inclement weather.
C.
Prevent contact with materials which may cause discoloration or staining.
1.08 COORDINATION
A.
Coordinate work under provisions of Section 01039.
B.
Coordinate with the work of Section 07532 for installation of the new roof system and
maintaining it weathertight on a daily basis.
PART 2
PRODUCTS
2.01 SHEET MATERIALS
A.
Galvanized Steel: ASTM A446, Grade A, G90 zinc coating; 24 gage core steel. To be
used for roof top unit curb flashings, counterflashings and pipe flashings.
2.02 ACCESSORIES
A.
Fasteners: Galvanized steel with soft neoprene washers.
B.
Primer: Zinc chromate type.
C.
Protective Backing Paint: Bituminous or approved equal.
D.
Sealant: Polyurethane type, specified in Section 07900.
E.
Plastic Cement: ASTM D4586, Type I.
F.
Solder: ASTM B32; 50/50 type.
G.
Flux: FS O-F-506.
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2.03 FABRICATION
A.
Form sections true to shape, accurate in size, square, and free from distortion or
defects.
B.
Fabricate cleats of same material as sheet, minimum 22 gauge, interlockable with
sheet.
C.
Form pieces in longest possible lengths in sheets.
D.
Hem exposed edges on underside 1/2 inch; miter and seam corners.
E.
Fabricate corners in perimeter edge metal and cap flashings from one piece with
minimum 18 inch long legs; for rigidity, seal with sealant. Shop fabricate all corner
pieces.
F.
Fabricate vertical faces with bottom edge formed outward 1/4 inch and hemmed to form
drip.
G.
Fabricate counterflashings to allow toe to extend 3 inches over roofing base flashing.
H.
Form sheet metal pans with 3 inch (75 mm) upstand, and 4 inch (100 mm) flanges, and
to provide a minimum clearance between inside edge of pan and penetration of 2
inches.
I.
Counterflashing shall be formed in not more than 10 foot lengths. Lap ends 3 inches
and caulk all loose lock joints. Cut and miter all inside and outside corner joints.
J.
All sheet metal penetration flashings (i.e., roof jacks, pitch pans, etc.,) and through wall
scuppers to have all seams soldered weathertight.
K.
Fabricate scuppers with a minimum extension beyond exterior face of the wall a
minimum of one inch. Fabricate to interlock conductor head.
L.
Fabricate scuppers and penetration flashings to be stripped into the roof with a
minimum 4-inch roof flange and solid corners. (Weld and solder corner pieces into roof
flanges where necessary.)
2.04 FINISH
A.
PART 3
Back paint concealed metal surfaces with protective backing paint to a minimum dry
film thickness of 15 mil.
EXECUTION
3.01 EXAMINATION
A.
Verify roof openings, curbs, pipes, sleeves, ducts, or vents through roof are solidly set,
reglets in place, and nailing strips located.
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B.
Verify roofing termination and base flashings are in place, sealed, and secure.
3.02 INSTALLATION
A.
Conform to drawing details included in the specification manual and to conform to
SMACNA and NRCA details.
B.
Secure flashings in place using concealed fasteners. [Use exposed fasteners only
where permitted.]
C.
Apply a full bed of water cut-off mastic compound between metal flashings and
membrane flashings and between lap joints in perimeter edge flashings.
D.
Fit flashings tight in place. Make corners square, surfaces true and straight in planes,
and lines accurate to profiles.
E.
Seal metal joints watertight.
F.
Finish all sheet metal weathertight.
G.
Where lap seams do not have a joint cover, lap according to pitch but in no case less
than 3 inches.
H.
Make all lap seams in the direction of water flow.
I.
Provide suitable watertight expansion joint as required for proper installation.
J.
Caulking of sheet metal where required shall be neatly and thoroughly performed for a
watertight seal.
K.
Provide continuous hook strip (cleat) for all perimeter edge and cap flashings and
secure a maximum of 16 inch o.c.
L.
For all sheet metal penetration flashings (roof jacks, pitch pans, etc.,) provide rain
collars/hoods installed over top of these flashings.
3.03 FASTENING
A.
Secure metal as per detailed drawings.
B.
For fastening into concrete, use masonry/concrete anchors with neoprene washers with
steel backing. Use all metal anchors only, no plastic anchors allowed.
C.
For exposed fastening into wood, use screws with neoprene washers.
D.
All fasteners to be corrosion resistant coated.
3.04 SOLDERING
A.
Thoroughly clean and tin all joint materials prior to soldering.
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B.
Use heavy soldering copper of a blunt design, properly tinned for use.
C.
Perform all soldering slowly with well-heated soldering copper in order to heat seams
thoroughly and to completely fill them in.
D.
Make all exposed soldering of finished surfaces neat, full-flowing, and smooth.
E.
After soldering, thoroughly wash and flux with a soda solution.
3.05 FIELD QUALITY CONTROL
A.
Field inspection will be performed under provisions of Section 01400.
B.
Inspection will involve surveillance of work during installation to ascertain compliance
with specified requirements.
C.
All roof surfaces to be adequately protected to prevent damage. Keep all scrap metal
off roof surface at all times. If damage to roof does occur; visibly mark area and report
immediately to roof contractor and/or Owner/Owner’s representative.
END OF SECTION 07620
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