07600_en.doc

SECTION 07600

FLASHING AND SHEET METAL

PART 1 - GENERAL

1.1

APPLICABLE PUBLICATIONS

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

Italian National Institute for the Unification of Standards (UNI) Publications:

UNI EN 13605

(2004) Copper and copper alloys - Copper profiles and profiled wire for electrical purposes.

UNI 4157

(1987) Bitumen for Roofing. Sampling and Acceptance Limits.

UNI 9001-2

(1987) Wrought primary aluminum and aluminum alloys. Aluminum group. Al 99,5 (1050 a).

UNI 5649-1

(1988) Copper. Wrought coppers. Qualities, requirements and tests.

UNI EN 10142

(2002) Continuously hot-dip zinc coated low carbon steels strip and sheet for cold forming. Technical Delivery Conditions.

UNI EN 10130

(2000) Cold rolled low carbon steel flat products for cold forming. Technical Delivery Conditions.

UNI EN 10051

(2000) Continuously hot-rolled uncoated plate, sheet and strip of non-alloy and alloy steels. Tolerances on dimensions and shape.

UNI EN 10152

(1994) Electrolytically zinc coated cold rolled steel flat products. Technical delivery conditions.

1.2 SUBMITTALS

1.2.1 Samples

Submit the following samples for approval:

a. Sheet Metal Materials: Two pieces 150 x 250 mm, of each type, and color.

1.2.2 Drawings

Submit shop drawings for approval, indicating thickness, dimensions, fastenings and anchoring methods, expansion joints, and other provisions necessary to provide for thermal expansion and contraction. Scaled catalogue cuts may be submitted for factory fabricated items. Submit shop drawings for the following items:

a.

Metal base, cap (counterflashing) and valley flashing.

b.

Flashing at all roof penetrations.

1.3

PRODUCT DELIVERY STORAGE AND HANDLING

Materials shall be adequately packaged and protected during shipment and inspected for damage, dampness, and wet-storage stains upon delivery to the job site. Damaged or permanently stained materials that cannot be restored to like-new condition shall be removed from the site and replaced at no additional cost to the Government. Carefully handle sheet metal items to avoid damage to surfaces, edges and ends. Crated materials shall not be uncrated until ready for use. Store materials in dry, weathertight, ventilated areas until immediately before installation.

PART 2 - PRODUCTS

2.1

GENERAL SHEET METAL

Sheet metal items shall be shop or factory fabricated. Furnish sheet metal items in 2.50 meter to 3.00 meter lengths. Single pieces less than 2.50 meters long may be used to connect to factory inside and outside corners, and at ends of runs. Accessories and other items essential to complete the sheet metal installation shall be provided and shall be of the same materials as the items to which they are applied.

2.2

MATERIALS

2.2.1 Steel Sheet, Zinc Coated (Galvanized)

UNI EN 10142

2.2.2 Stainless Steel

Shall be fully annealed, dead soft temper with slow cold-rolled dull finish. Stainless steel shall be made by the electric-arc process, electric-induction process or other suitable process.

Stainless steel shall have the following chemical compositions:

Carbon 0.15

+0.005

Manganese 2.0

+0.04

Phosphorus 0.045

+0.010

Sulfur 0.030

+0.005

Silicon 0.75

+0.05

Chromium 17.0-19.0 +0.20

Nickel 8.0-10.0 +0.10

Other

0.10 Max.

Stainless steel shall have the following mechanical properties:

Tensile Strength 515 mPa minimum

Yield Strength 205 mPa minimum

Elongation in 50 mm 40.0% minimum

Brinell Hardness 201 maximum

Rockwell B Hardness 92 maximum

The material shall be of uniform quality consistent with good manufacturing and inspection practices. The steel shall have no imperfections of a nature or degree that will adversely affect the stamping, forming, machining, or fabrication of finished parts. Refer to Table I at the end of this section for required weights and thickness.

2.2.3 Aluminum Alloy Sheet and Plate

UNI 9001-2.

2.2.4 Soldering Flux

Use an approved acid type flux for steel.

2.2.5 Solder

50 percent pig lead and 50 percent pure block tin.

2.2.6 Polyvinyl Chloride Reglet

2 mm minimum thickness.

2.2.7 Bituminous Plastic Cement

Shall be an asphaltic base material compatible with the roofing asphalts and asphalt primer.

2.2.8 Copper

Copper sheet or strip shall be a cold-rolled tempered flat product of the weight listed in Table I at the end of this section. Lengths shall not exceed 3 meters. The quality of the materials shall comply with the following tables.

Mechanical Requirements

Tensile Yield Strength

Yield Strength Approximate

Strength (mPa) at 5% at 2% Rockwell

Extension

Extension

Hardness

Under Load

Under Load

Min. Max.

Min. mPa

Min. mPa

F Scale Superficial 30T 220 275

60-82 25-49

The material shall have a minimum copper and silver content of 99.9 percent. The material shall be free from defects of a nature that interfere with normal commercial operations, shall be well cleaned, and shall be free from dirt.

2.2.9 Fasteners

Fasteners shall be the same metal or a metal compatible with the item fastened. Use aluminum fasteners with aluminum; and stainless steel fasteners with stainless steel and to fasten dissimilar materials. Use copper or stainless steel nails with copper.

2.2.10 Optional Materials

Optional materials are listed in Table I. Any of the optional materials specified therein may be selected by the Contractor; however, all exposed sheet metal items shall be of the same material, prefabricated, with a factory baked enamel finish, unless indicated otherwise. Colors will be selected by the Contracting Officer’s Technical Representative. The following items shall be considered as exposed sheet metal: Gutters, including hangers; downspouts and leaders; fascias; copings, roof edges and trim, cap and eave flashing.

2.2.11 Sheet Metal

Provide flashing in the roof valleys and where roof decks abut walls, curbs, ventilators, pipes or other vertical surfaces and wherever indicated and necessary to make the work watertight. All aluminum sheet metal shall be pre-finished unless specified otherwise herein. Tempers of metals shall be suitable for their respective forming conditions. Fabricate sheet metal items to the gage, thickness or weight shown in Table I and join multiple lengths of items together as shown in Table II.

PART 3 - EXECUTION

3.1

GENERAL

Comply with the hereinafter paragraphs as applicable to this project.

Surfaces to receive sheet metal must be plumb and true, clean, even, smooth, dry and free from defects and projections which might affect the application.

3.2

WORKMANSHIP

Install sheet metal work with lines, arises, and angles sharp and true. Exposed surfaces shall be free from visible wave, warp, and buckle, and tool marks. Exposed edges shall be folded back neatly to form a 15 millimeter hem on the concealed side. Sheet metal exposed to the weather shall be watertight with provisions for expansion and contraction.

3.3

NAILING

Nailing of sheet metal shall be confined generally to sheet metal having a maximum width of 500 mm. Nailing of flashing shall be confined to one edge only. Nails shall be evenly spaced not over 80 mm on centers and approximately 15 millimeters from edge unless otherwise specified or indicated. Face nailing will not be permitted. Where sheet metal is applied to other than wood surfaces, detailed shop drawings shall include locations for sleepers and nailing strips required to properly secure the work. Sleepers and nailing strips are specified in Section 06100, "Rough Carpentry".

3.4 CLEATS

Provide cleats for sheet metal 100 mm and over in width. Space cleats evenly not over 300 mm on centers unless otherwise specified or indicated. Cleats shall be not less than 50 millimeters wide x 75 millimeters long and of the same material and thickness as the sheet metal being installed. For cleats used in conjunction with flashing: One end of the cleat shall be secured with nails and the cleat folded back over the nail-heads. Cleats for soldered seams shall be pre-tinned.

3.5

BOLTS, RIVETS AND SCREWS

Install bolts, rivets and screws where indicated or required. Provide compatible washers where required to protect surface of sheet metal and to provide a watertight connection.

3.6

SEAMS

Straight and uniform in width and height with no solder showing on the face.

3.6.1 Flat-Lock Seams

Finish not less than 20 millimeters wide.

3.6.2 Lap Seams

Finish soldered seams not less than 25 millimeters wide. Overlap seams not soldered, not less than 75 millimeters.

3.6.3 Loose-lock Expansion Seams

Not less than 75 millimeters wide, and shall provide minimum 25 millimeters movement within the joint. Joints shall be completely filled with the specified sealant, applied at not less than 3 millimeters thick bed. Sealants are specified in Section 07920, "Joint Sealants".

3.6.4 Flat Seams

Make seams in the direction of the flow.

3.7

SOLDERING, WELDING, AND MECHANICAL FASTENING

Where soldering is specified herein it shall apply to copper, zinc coated steel and stainless steel items. Welding is specified for aluminum of thickness greater than 1 millimeter. Aluminum 1 millimeter or less in thickness shall be butted with space and backed with formed flashing plate; or lock joined, mechanically fastened, and filled with sealant as recommended by the aluminum manufacturer.

3.7.1 Soldering

Pre-tin edges of sheet metals, except lead coated material, before soldering is begun. Soldering shall be done slowly with well heated soldering irons so as to thoroughly heat the seams and completely sweat the solder through the full width of the seam. Edges of lead-coated material to be soldered shall be scraped or wire-brushed to produce a bright surface, and seams shall have a liberal amount of flux brushed in before soldering is begun. Edges of stainless steel to be pre-tinned shall be treated with soldering acid flux. Upon completion of soldering the acid flux residue shall be thoroughly cleaned from the sheet metal with solution of washing soda in water and rinsed with clean water. Joints in aluminum sheets 1 millimeter or less in thickness shall be made mechanically and sealed with the sealant specified. Aluminum shall not be soldered.

3.7.2 Welding of Aluminum

Joints in aluminum sheets more than 1 millimeter thick shall be welded. Welding shall be of the inert gas, shield-arc type. The procedures, the appearance and quality of welds made, and the methods used in correcting welding work shall conform to the aluminum manufacturer's recommendations.

3.7.3 Mechanical Fastening of Aluminum

Aluminum alloy sheet metal screws or other suitable aluminum alloy or stainless steel fasteners shall be driven in holes made with a 4 millimeter diameter drill, shall be used in securing side laps, end laps, and flashing. Maximum spacing for fasteners shall be 300 mm. Where end lap fasteners are required to improve closure, they shall be located not more than 50 mm from the end of the overlapping sheet.

3.8

PROTECTION FROM CONTACT OF DISSIMILAR MATERIALS

3.8.1 Copper or Copper-bearing Alloys

Surfaces in contact with dissimilar metal shall be painted with heavy-bodied bituminous paint, or shall be separated by means of moisture proof building felts.

3.8.2 Aluminum

Surfaces shall not contact other metals except stainless steel, zinc, or zinc coating. Where aluminum contacts another metal, the dissimilar metal shall be painted with a primer followed by two coats of aluminum paint.

3.8.3 All Metal

Surfaces in contact with mortar or concrete materials shall be painted with alkali-resistant coatings such as heavy-bodied bituminous paint.

3.8.4 Wood or Other Absorptive Materials

Surfaces that may become repeatedly wet and in contact with metal shall be painted with two coats of aluminum paint or a coat of heavy-bodied bituminous paint.

3.8.5 Dissimilar Metal

Paint with a non-lead pigmented paint if drainage from it passes over aluminum.

3.9

PROVISION FOR EXPANSION AND CONTRACTION

Provide expansion and contractor joints at not more than 10 meter intervals for aluminum and at not more than 12 meter intervals for other metals, except that where the distance between the last expansion joint and the end of the continuous run is more than half the required interval spacing an additional joint shall be provided. Space joints evenly. Extruded aluminum copings and fascias shall be joined by expansion and contraction joints at not more than 4 meter spacing.

3.10

BASE FLASHING

Where sloped roofs abut chimneys, curbs, walls, or other vertical surfaces, the base flashings shall be laid in with the roof covering. The flashing shall extend up vertical surfaces under or over roof covering as indicated. Where finish wall coverings form a counterflashing, the vertical leg of the flashing shall extend up behind the applied wall covering not less than 150 mm, otherwise the vertical leg of the flashing shall extend up behind a continuous counterflashing and reglet system. Flashings shall be installed and fitted so as to be completely weathertight. Strips shall be fastened at their upper edge to the deck, with compatible large-head roofing nails. End laps shall be soldered, except that provision shall be made for expansion and contraction. At the up-slope side of vertical surfaces extending through the roof decks, metal flashings shall extend over crickets. At the lower side of vertical surfaces extending through the roof decks, metal flashings shall extend onto the roof covering not less than 10 centimeters. Flashings shall be installed and fitted so as to be completely weathertight.

3.11 Valley Flashing

Where sloped roofs meet, the valley flashings shall be laid in with the roof covering. The flashing shall extend beneath both sides of roof covering and be secured to cleats as indicated and specified. Valley flashing shall be fabricated in longest sections possible to minimize the number of joints. Valley flashing shall overlap a minimum of 200 mm in the direction of flow. The top of each section of valley flashing shall be secured to the roof construction with a minimum of six fasteners; the fasteners shall be compatible with the flashing. The edges of the valley flashing shall be formed with hook edges to be compatible with the cleats.

3.12

COUNTERFLASHING

Except where indicated or specified otherwise, insert counterflashing in reglets located from 200 to 250 mm above roof decks and extend down vertical 100 millimeters minimum over upturned vertical leg of base flashing or continuous hook strip not less than 75 millimeters. Exposed edges of counterflashings shall be folded 15 millimeters. Where stepped counterflashings are required, they may be installed in short lengths or may be of the preformed one-piece type. End laps in counterflashings shall be not less than 75 millimeters and shall be made weathertight with plastic cement. Lengths of metal counterflashings shall not exceed 3 meters. The flashing shall be formed to the required shapes prior to installation. Corners shall be factory formed with joints not less than 300 mm from the angle. Flashing shall be secured in the reglets with lead wedges spaced not to exceed 450 mm apart; on short runs, wedges shall be placed closer together. Calked-type reglets or raked joints that will receive counterflashing shall be filled with calking compound. Calking is covered in Section 07920, "Joint Sealants". The concealed edge of counterflashings built into concrete walls shall be turned up not less than 50 millimeters into the walls. Counterflashing shall provide a spring action against base flashing.

3.13

METAL REGLETS

3.13.1 Friction-type Reglets

Provide with flashing receiving slots not less than 15 millimeters deep, 2.5 centimeters jointing tongues, and upper and lower anchoring flanges. The flashing shall be inserted the full depth of the slot and locked therein by indentations made with a dull-pointed tool.

3.13.2 Calked-type Reglets

Provide with rounded edges and metal strap brackets or other approved anchors for securing to the concrete forms. They shall be provided with an approved type core to protect them from injury during the installation. Built-up mitered corner pieces shall be provided for internal and external angles. Flashing shall be wedged in the reglets with lead wedges every 45 centimeters and shall be calked full and solid with an approved compound.

3.14

ROOF EDGE FASCIAS AND TRIM

Fabricate in the shapes and sizes indicated and in lengths not less than 2.50 meters. Extend flanges at least 100 millimeters onto roof deck. Extend the vertical face at least 50 millimeters beyond the roofing and insulation onto the wall face. Provide prefabricated mitered corners for internal and external corners. Set flange on top of wood rail or in a 3 millimeters thick bed of plastic cement. Nail flange securely to wood nailer with large-head barbed-shank roofing nails 35 millimeters long spaced not more than 75 millimeters on centers. Finish shall be baked enamel, color as approved.

3.14.1 Hook Strips

The lower edge of fascias shall be hooked at least 20 millimeters over a continuous hook strip of the same material bent outward at an angle of 45 degrees to form a drip. Nail hook strip to a wood nailer at 150 mm maximum on centers. Where fastening is made to concrete, screws spaced 300 mm on center shall be used and shall be driven in expansion shields set in the concrete. Where horizontal wood nailers are slotted to provide for insulation venting, install hook strips in such a manner that vent slots are not obstructed. Where necessary, install hook strips over 2 millimeters thick compatible spacer or washers.

3.14.2 Joints

Section ends of gravel stops, copings and fascias shall be left open 6 millimeters and backed with a formed flashing plate, mechanically fastened in place and lapping each section end a minimum of 100 millimeters; set laps in plastic cement. Face nailing will not be permitted. Extruded aluminum gravel stops, copings and fascias shall be installed in accordance with the manufacturer's printed instructions and details.

3.14.3 Metal Drip Edge

Provide a metal drip, designed to allow water run-off to drip free of underlying construction as indicated. Apply directly on the wood blocking at the eaves and over the underlay along the rakes, extend back from the edge of the deck not more than 100 mm and secure with compatible nails spaced not more than 250 mm on center along upper edge.

3.15 GUTTERS

The hung type of shape indicated and supported on underside by brackets that permit free thermal movement of the gutter. Provide gutters in sizes indicated complete with mitered corners, end caps, outlets, brackets, and other accessories necessary for installation. The outer edge of gutter shall be beaded or reinforced with a stiffening bar not less than 20 millimeters by 5 millimeters of material compatible with gutter. Gutters shall be fabricated in sections not less than 2.50 meters long. The sections shall be lapped a minimum of 25 millimeters in the direction of flow. Gutters shall be joined by riveted and soldered joints. Expansion type slip joints shall be provided midway between outlets. Install gutters below slope line of the roof so that snow and ice can slide clear. Support gutters on approved type adjustable hangers spaced not more than 800 mm on centers. Gutters shall be adjusted to slope uniformly to outlets, with high points occurring as required. Hangers and fastenings shall be fabricated from metals compatible with the gutters. Finish shall be baked enamel, color as approved.

3.16

DOWNSPOUT

The circular type, 110 mm in diameter, and provided complete including elbows and offsets. Downspouts shall be provided in approximately 3.5 meters lengths; end joints shall telescope not less than 12 millimeters, and longitudinal joints shall be locked. Gutter outlets shall be provided with wire wall strainers of a standard type for each outlet. Strainers shall fit tightly into outlets and shall be of the same material used for gutters. Downspouts shall be kept not less than 25 millimeters away from walls and shall be fastened to the walls at top, bottom, and are not to exceed 1.50 meter centers intermediately between, with approved type leader straps or concealed rack-and-pin type fasteners; straps and fasteners shall be formed from metal compatible with the downspouts. Downspouts terminating in drainage lines shall be neatly fitted into the drainage connection and the joint filled with a Portland cement mortar cap sloped away from the downspout. Downspouts terminating in splash blocks shall be provided with elbow-type fittings. Splash blocks shall be concrete as specified in Section 03300, "Cast-in-Place Concrete". Finish shall be baked enamel, color as approved. Downspout end shall be coated with a 1.50 meter cast-iron pipe.

3.17

FLASHING AT ROOF PENETRATIONS AND EQUIPMENT SUPPORTS

Provide metal flashing for all pipes, ducts, and conduits projecting through the roof surface and for equipment supports, antenna supports, anchors and similar items supported by or attached to the roof deck. Hot exhaust thimble assemblies, power roof ventilators, and exhaust fans, are specified in mechanical Section 15810 “Ductwork and Ductwork Accessories”.

3.17.1 Single Pipe Vents

Flash with a 1 mm thick minimum lead sleeve having a 100 mm flange. Set flange in bituminous plastic cement and nail 80 mm on centers. Top of sleeve shall be bent over and extended down into the vent pipe a minimum of 50 mm.

3.18

PAINTING

Sheet metal work shall not be field painted except as required for the separation of dissimilar metals or for compliance with design requirements. Where painting is specified it shall be factory finished baked enamel.

3.19

CLEANING

Clean all exposed sheet metal work at completion of installation. Grease and oil films, handling marks, contamination from steel wool, fittings and drilling debris shall be removed and the work scrubbed clean. All exposed metal surfaces shall be free of dents, creases, waves, scratch marks, and solder or weld marks.

3.20

REPAIR TO FINISH

Scratches, abrasions, and minor surface defects of finish may be repaired in accordance with the manufacturer's printed instructions and as approved. Finished repaired surfaces shall be uniform and free from scratches, blemishes, and from variations of color and surface texture.

TABLE I.

SHEET METAL WEIGHTS AND THICKNESSES

Galvanized

Steel Copper Stainless Steel mm mm kg/sqm mm

Downspouts and leaders 8/10 4.9

Downspout straps, 5 cm

14.7 brass

Strainers, wire diameter

4 Gage

Flashing:

Base 1.02

6.125 0.45

Cap (Counterflashing)...

0.81

4.49 0.37

Eave

Coping and fascias:

Sheets, smooth………..

Edge strip and trim………

7.35

Gutters:

Gutter section

Continuous cleat

Hangers

25 mm x 3 mm (a)

Cover plates 0.81 4.9 0.38

(a) Brass

TABLE II. SHEET METAL JOINTS

TYPE OF JOINT

Copper, Item

Stainless

Designation

Steel

Remarks

Flashing:

Base 25 mm flat locked, Each expansion joint soldered, 75 mm lap for all metals shall for expansion be filled with a joint.

joint sealing compound.

See Section 07920

"Joint Sealants".

Valley 200 mm overlap in direction of flow.

Cap-in 80 mm lap

80 mm lap

Reglet

Reglets Butt joint Seal reglet groove with joint sealing compound, Section 07920, "Joint

Sealants".

TABLE II. SHEET METAL JOINTS (continued)

TYPE OF JOINT

Copper, Item

Stainless

Designation

Steel

Aluminum Remarks

Eave

25 mm flat locked, Same as base flashing.

cleated, 25 mm loose locked, sealed expansion joint, cleated.

Sheet, Smooth Butt with space Butt with space Use sheet flashing back-up plate.

Gutters

5 cm lap, riveted and soldered.

-- End of Section --

Section 07600

Section 07600