HomeMy WebLinkAbout07620.pdf BICKFORD OF CARMEL, IN 12/12/2012
SHEET METAL FLASHING AND TRIM 07620 - 1
SECTION 07620 - SHEET METAL FLASHING AND TRIM
PART 1 - GENERAL
1.1 RELATED DOCUMENTS
A. Drawings and general provisions of the Contract, including General and Supplementary
Conditions and Division 1 Specification Sections, apply to this Section.
1.2 SUMMARY
A. Section Includes:
1. Formed Products:
a. Formed roof drainage sheet metal fabrications.
b. Formed steep-slope roof sheet metal fabrications.
c. Formed wall sheet metal fabrications.
B. Related Sections:
1. Division 6 Section " Miscellaneous Carpentry" for wood nailers, curbs, and blocking.
2. Division 7 Section "Shingles" for installing sheet metal flashing and trim integral with
roofing.
3. Division 7 Section "Roof Accessories" for set-on-type curbs, equipment supports, roof
hatches, vents, and other manufactured roof accessory units.
1.3 PERFORMANCE REQUIREMENTS
A. General: Sheet metal flashing and trim assemblies as indicated shall withstand wind loads,
structural movement, thermally induced movement, and exposure to weather without failure due
to defective manufacture, fabrication, installation, or other defects in construction. Completed
sheet metal flashing and trim shall not rattle, leak, or loosen, and shall remain watertight.
B. Thermal Movements: Provide sheet metal flashing and trim that allows for thermal movements
from ambient and surface temperature changes.
1. Temperature Change (Range): 120 deg F (67 deg C), ambient; 180 deg F (100 deg C),
material surfaces.
1.4 QUALITY ASSURANCE
A. Fabricator Qualifications: Shop that employs skilled workers who custom fabricate sheet metal
flashing and trim similar to that required for this Project and whose products have a record of
successful in-service performance.
B. Sheet Metal Flashing and Trim Standard: Comply with SMACNA's "Architectural Sheet Metal
Manual" unless more stringent requirements are specified or shown on Drawings.
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1.5 DELIVERY, STORAGE, AND HANDLING
A. Do not store sheet metal flashing and trim materials in contact with other materials that might
cause staining, denting, or other surface damage. Store sheet metal flashing and trim materials
away from uncured concrete and masonry.
B. Protect strippable protective covering on sheet metal flashing and trim from exposure to sunlight
and high humidity, except to the extent necessary for the period of sheet metal flashing and trim
installation.
PART 2 - PRODUCTS
2.1 SHEET METALS
A. General: Protect mechanical and other finishes on exposed surfaces from damage by applying
a strippable, temporary protective film before shipping.
B. Aluminum Sheet: ASTM B 209 (ASTM B 209M), alloy as standard with manufacturer for finish
required, with temper as required to suit forming operations and performance required.
1. As-Milled Finish: Standard two-side bright finish.
2. Surface: Smooth, flat.
3. Factory Prime Coating: Where painting after installation is indicated, pretreat with white
or light-colored, factory-applied, baked-on epoxy primer coat; minimum dry film thickness
of 0.2 mil (0.005 mm).
4. Color Anodic Finish, Coil Coated: AAMA 611, AA-M12C22A42/A44, Class I, 0.018 mm
or thicker.
a. Color: white.
b. Color Range: Noticeable variations in same piece are not acceptable. Variations
in appearance of adjoining components are acceptable if they are within the range
of approved Samples and are assembled or installed to minimize contrast.
5. Color: white.
6. Concealed Finish: Pretreat with manufacturer's standard white or light-colored acrylic or
polyester backer finish, consisting of prime coat and wash coat with a minimum total dry
film thickness of 0.5 mil (0.013 mm).
C. Metallic-Coated Steel Sheet: Restricted flatness steel sheet, metallic coated by the hot-dip
process and prepainted by the coil-coating process to comply with ASTM A 755/A 755M.
1. Aluminum-Zinc Alloy-Coated Steel Sheet: ASTM A 792/A 792M, Class AZ50 coating
designation, Grade 40 (Class AZM150 coating designation, Grade 275); structural
quality.
2. Surface: Smooth, flat and mill phosphatized for field painting.
3. Exposed Coil-Coated Finish:
a. Two-Coat Fluoropolymer: AAMA 621. Fluoropolymer finish containing not less
than 70 percent PVDF resin by weight in color coat. Prepare, pretreat, and apply
coating to exposed metal surfaces to comply with coating and resin manufacturers'
written instructions.
b. Siliconized Polyester: Epoxy primer and silicone-modified, polyester-enamel
topcoat; with a dry film thickness of not less than 0.2 mil (0.005 mm) for primer and
0.8 mil (0.02 mm) for topcoat.
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4. Color: white.
5. Concealed Finish: Pretreat with manufacturer's standard white or light-colored acrylic or
polyester backer finish, consisting of prime coat and wash coat with a minimum total dry
film thickness of 0.5 mil (0.013 mm).
2.2 MISCELLANEOUS MATERIALS
A. General: Provide materials and types of fasteners, solder, welding rods, protective coatings,
separators, sealants, and other miscellaneous items as required for complete sheet metal
flashing and trim installation and recommended by manufacturer of primary sheet metal or
manufactured item unless otherwise indicated.
B. Fasteners: Wood screws, annular threaded nails, self-tapping screws, self-locking rivets and
bolts, and other suitable fasteners designed to withstand design loads and recommended by
manufacturer of primary sheet metal or manufactured item.
1. General: Blind fasteners or self-drilling screws, gasketed, with hex-washer head.
a. Exposed Fasteners: Heads matching color of sheet metal using plastic caps or
factory-applied coating.
b. Blind Fasteners: High-strength aluminum or stainless-steel rivets suitable for
metal being fastened.
c. Spikes and Ferrules: Same material as gutter; with spike with ferrule matching
internal gutter width.
2. Fasteners for Aluminum Sheet: Aluminum or Series 300 stainless steel.
3. Fasteners for Aluminum-Zinc Alloy-Coated Steel Sheet: Hot-dip galvanized steel
according to ASTM A 153/A 153M or ASTM F 2329 or Series 300 stainless steel.
C. Solder:
D. Sealant Tape: Pressure-sensitive, 100 percent solids, gray polyisobutylene compound sealant
tape with release-paper backing. Provide permanently elastic, nonsag, nontoxic, nonstaining
tape 1/2 inch (13 mm) wide and 1/8 inch (3 mm) thick.
E. Elastomeric Sealant: ASTM C 920, elastomeric polyurethane polymer sealant; low modulus; of
type, grade, class, and use classifications required to seal joints in sheet metal flashing and trim
and remain watertight.
F. Butyl Sealant: ASTM C 1311, single-component, solvent-release butyl rubber sealant;
polyisobutylene plasticized; heavy bodied for hooked-type expansion joints with limited
movement.
G. Epoxy Seam Sealer: Two-part, noncorrosive, aluminum seam-cementing compound,
recommended by aluminum manufacturer for exterior nonmoving joints, including riveted joints.
H. Bituminous Coating: Cold-applied asphalt emulsion complying with ASTM D 1187.
I. Asphalt Roofing Cement: ASTM D 4586, asbestos free, of consistency required for application.
2.3 FABRICATION, GENERAL
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A. General: Custom fabricate sheet metal flashing and trim to comply with recommendations in
SMACNA's "Architectural Sheet Metal Manual" that apply to design, dimensions, geometry,
metal thickness, and other characteristics of item indicated. Fabricate items at the shop to
greatest extent possible.
1. Fabricate sheet metal flashing and trim in thickness or weight needed to comply with
performance requirements, but not less than that specified for each application and
metal.
2. Obtain field measurements for accurate fit before shop fabrication.
3. Form sheet metal flashing and trim without excessive oil canning, buckling, and tool
marks and true to line and levels indicated, with exposed edges folded back to form
hems.
4. Conceal fasteners and expansion provisions where possible. Exposed fasteners are not
allowed on faces exposed to view.
B. Fabrication Tolerances: Fabricate sheet metal flashing and trim that is capable of installation to
tolerances specified in MCA's "Guide Specification for Residential Metal Roofing."
C. Sealed Joints: Form non-expansion but movable joints in metal to accommodate elastomeric
sealant.
D. Expansion Provisions: Where lapped expansion provisions cannot be used, form expansion
joints of intermeshing hooked flanges, not less than 1 inch (25 mm) deep, filled with butyl
sealant concealed within joints.
E. Fabricate cleats and attachment devices from same material as accessory being anchored or
from compatible, noncorrosive metal.
F. Fabricate cleats and attachment devices of sizes as recommended by SMACNA's "Architectural
Sheet Metal Manual" for application, but not less than thickness of metal being secured.
G. Seams: Fabricate nonmoving seams with flat-lock seams. Form seams and seal with
elastomeric sealant unless otherwise recommended by sealant manufacturer for intended
use. Rivet joints where necessary for strength.
H. Do not use graphite pencils to mark metal surfaces.
2.4 ROOF DRAINAGE SHEET METAL FABRICATIONS
A. Hanging Gutters: Fabricate to cross section indicated, complete with end pieces, outlet tubes,
and other accessories as required. Fabricate in minimum 96-inch- (2400-mm-) long sections.
Furnish flat-stock gutter spacers and gutter brackets fabricated from same metal as gutters, of
size recommended by SMACNA but not less than twice the gutter thickness. Fabricate
expansion joints, expansion-joint covers, gutter bead reinforcing bars, and gutter accessories
from same metal as gutters.
1. Gutter Style: SMACNA designation ‘Ogee’.
2. Expansion Joints: Lap type.
3. Accessories: Wire ball downspout strainer and Valley baffles.
4. Gutters with Girth 16 to 20 Inches (410 to 510 mm): Fabricate from the following
materials:
a. Aluminum: 0.040 inch (1.02 mm) thick.
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B. Downspouts: Fabricate rectangular downspouts complete with mitered elbows. Furnish with
metal hangers, from same material as downspouts, and anchors.
1. Fabricate from the following materials:
a. Aluminum: 0.024 inch (0.61 mm) thick.
2.5 STEEP-SLOPE ROOF SHEET METAL FABRICATIONS
A. Apron, Step, Cricket, and Backer Flashing: Fabricate from the following materials:
1. Aluminum: 0.032 inch (0.81 mm) thick.
B. Valley Flashing: Fabricate from the following materials:
1. Aluminum-Zinc Alloy-Coated Steel: 0.028 inch (0.71 mm) thick.
C. Drip Edges: Fabricate from the following materials:
1. Aluminum: 0.032 inch (0.81 mm) thick.
D. Eave, Rake Flashing: Fabricate from the following materials:
1. Aluminum: 0.032 inch (0.81 mm) thick.
E. Counterflashing: Fabricate from the following materials:
1. Aluminum: 0.032 inch (0.81 mm) thick.
F. Roof-Penetration Flashing: Fabricate from the following materials:
1. Aluminum-Zinc Alloy-Coated Steel: 0.028 inch (0.71 mm) thick.
2.6 WALL SHEET METAL FABRICATIONS
A. Opening Flashings in Frame Construction: Fabricate head, sill, and similar flashings to extend
4 inches (100 mm) beyond wall openings. Form head and sill flashing with 2-inch- (50-mm-)
high, end dams. Fabricate from the following materials:
1. Aluminum: 0.032 inch (0.81 mm) thick.
PART 3 - EXECUTION
3.1 EXAMINATION
A. Examine substrates, areas, and conditions, with Installer present, to verify actual locations,
dimensions and other conditions affecting performance of the Work.
1. Verify that substrate is sound, dry, smooth, clean, sloped for drainage, and securely
anchored.
B. For the record, prepare written report, endorsed by Installer, listing conditions detrimental to
performance of the Work.
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C. Proceed with installation only after unsatisfactory conditions have been corrected.
3.2 INSTALLATION, GENERAL
A. General: Anchor sheet metal flashing and trim and other components of the Work securely in
place, with provisions for thermal and structural movement. Use fasteners, solder, welding
rods, protective coatings, separators, sealants, and other miscellaneous items as required to
complete sheet metal flashing and trim system.
1. Install sheet metal flashing and trim true to line and levels indicated. Provide uniform,
neat seams with minimum exposure of solder, welds, and sealant.
2. Install sheet metal flashing and trim to fit substrates and to result in watertight
performance. Verify shapes and dimensions of surfaces to be covered before fabricating
sheet metal.
3. Space cleats not more than 12 inches (300 mm) apart. Anchor each cleat with two
fasteners. Bend tabs over fasteners.
4. Install exposed sheet metal flashing and trim without excessive oil canning, buckling, and
tool marks.
5. Install sealant tape where indicated.
6. Torch cutting of sheet metal flashing and trim is not permitted.
7. Do not use graphite pencils to mark metal surfaces.
B. Metal Protection: Where dissimilar metals will contact each other or corrosive substrates,
protect against galvanic action by painting contact surfaces with bituminous coating or by other
permanent separation as recommended by SMACNA.
1. Coat back side of uncoated aluminum sheet metal flashing and trim with bituminous
coating where flashing and trim will contact wood, ferrous metal, or cementitious
construction.
C. Expansion Provisions: Provide for thermal expansion of exposed flashing and trim. Space
movement joints at a maximum of 10 feet (3 m) with no joints allowed within 24 inches (600
mm) of corner or intersection. Where lapped expansion provisions cannot be used or would not
be sufficiently watertight, form expansion joints of intermeshing hooked flanges, not less than 1
inch (25 mm) deep, filled with sealant concealed within joints.
D. Fastener Sizes: Use fasteners of sizes that will penetrate wood sheathing not less than 1-1/4
inches (32 mm) for nails and not less than 3/4 inch (19 mm) for wood screws.
E. Seal joints as shown and as required for watertight construction.
1. Where sealant-filled joints are used, embed hooked flanges of joint members not less
than 1 inch (25 mm) into sealant. Form joints to completely conceal sealant. When
ambient temperature at time of installation is moderate, between 40 and 70 deg F (4 and
21 deg C), set joint members for 50 percent movement each way. Adjust setting
proportionately for installation at higher ambient temperatures. Do not install sealant-type
joints at temperatures below 40 deg F (4 deg C).
2. Prepare joints and apply sealants to comply with requirements in Division 7 Section "Joint
Sealants."
F. Soldered Joints: Clean surfaces to be soldered, removing oils and foreign matter. Pre-tin
edges of sheets to be soldered to a width of 1-1/2 inches (38 mm), except reduce pre-tinning
where pre-tinned surface would show in completed Work.
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1. Do not solder metallic-coated steel and aluminum sheet.
2. Do not use torches for soldering. Heat surfaces to receive solder and flow solder into
joint. Fill joint completely. Completely remove flux and spatter from exposed surfaces.
G. Rivets: Rivet joints in uncoated aluminum where indicated and where necessary for strength.
3.3 ROOF DRAINAGE SYSTEM INSTALLATION
A. General: Install sheet metal roof drainage items to produce complete roof drainage system
according to SMACNA recommendations and as indicated. Coordinate installation of roof
perimeter flashing with installation of roof drainage system.
B. Hanging Gutters: Join sections with riveted and soldered joints or with lapped joints sealed with
sealant. Provide for thermal expansion. Attach gutters at eave or fascia to firmly anchored
gutter brackets spaced not more than 36 inches (900 mm) apart. Provide end closures and seal
watertight with sealant. Slope to downspouts.
1. Fasten gutter spacers to front and back of gutter.
2. Loosely lock straps to front gutter bead and anchor to roof deck.
3. Anchor and loosely lock back edge of gutter to continuous eave or apron flashing.
4. Install gutter with expansion joints at locations indicated, but not exceeding, 50 feet
(15.24 m) apart. Install expansion-joint caps.
C. Downspouts: Join sections with 1-1/2-inch (38-mm) telescoping joints.
1. Provide hangers with fasteners designed to hold downspouts securely to walls. Locate
hangers at top and bottom and at approximately 60 inches (1500 mm) o.c. in between.
2. Provide elbows at base of downspout to direct water away from building.
3. Connect downspouts to underground drainage system indicated.
3.4 ROOF FLASHING INSTALLATION
A. General: Install sheet metal flashing and trim to comply with performance requirements, sheet
metal manufacturer's written installation instructions, and SMACNA's "Architectural Sheet Metal
Manual." Provide concealed fasteners where possible, set units true to line, and level as
indicated. Install work with laps, joints, and seams that will be permanently watertight and
weather resistant.
B. Roof Edge Flashing: Anchor to resist uplift and outward forces according to recommendations
in SMACNA's "Architectural Sheet Metal Manual" and as indicated. Interlock bottom edge of
roof edge flashing with continuous cleat anchored to substrate at staggered 3-inch (75-mm)
centers.
C. Pipe or Post Counterflashing: Install counterflashing umbrella with close-fitting collar with top
edge flared for elastomeric sealant, extending a minimum of 4 inches (100 mm) over base
flashing. Install stainless-steel draw band and tighten.
D. Counterflashing: Coordinate installation of counterflashing with installation of base flashing.
Insert counterflashing in reglets or receivers and fit tightly to base flashing. Extend
counterflashing 4 inches (100 mm) over base flashing. Lap counterflashing joints a minimum of
4 inches (100 mm) and bed with sealant. Secure in a waterproof manner by means of
interlocking folded seam or blind rivets and sealant.
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E. Roof-Penetration Flashing: Coordinate installation of roof-penetration flashing with installation
of roofing and other items penetrating roof. Seal with butyl sealant and clamp flashing to pipes
that penetrate roof.
3.5 WALL FLASHING INSTALLATION
A. General: Install sheet metal wall flashing to intercept and exclude penetrating moisture
according to SMACNA recommendations and as indicated. Coordinate installation of wall
flashing with installation of wall-opening components such as windows, doors, and louvers.
B. Opening Flashings in Frame Construction: Install continuous head, sill, and similar flashings to
extend 4 inches (100 mm) beyond wall openings.
3.6 ERECTION TOLERANCES
A. Installation Tolerances: Shim and align sheet metal flashing and trim within installed tolerances
specified in MCA's "Guide Specification for Residential Metal Roofing."
3.7 CLEANING AND PROTECTION
A. Clean exposed metal surfaces of substances that interfere with uniform oxidation and
weathering.
B. Clean and neutralize flux materials. Clean off excess solder.
C. Clean off excess sealants.
D. Remove temporary protective coverings and strippable films as sheet metal flashing and trim
are installed unless otherwise indicated in manufacturer's written installation instructions. On
completion of installation, remove unused materials and clean finished surfaces. Maintain in a
clean condition during construction.
E. Replace sheet metal flashing and trim that have been damaged or that have deteriorated
beyond successful repair by finish touchup or similar minor repair procedures.
END OF SECTION 07620