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O U T L I N E   G U I D E

DIVISION 7:  THERMAL AND MOISTURE PROTECTION

SECTION 07620 ‑ SHEET METAL FLASHING AND TRIM

USE:	Furnishing and installing sheet metal flashing and trim.  Unique job requirements may require specific coverage in the following specification sections:  

NOTES TO SPECIFIER:

A.	Options within paragraphs are identified by enclosure in brackets; blank spaces enclosed by brackets [      ] provide for information to be inserted, as appropriate to individual projects.

B.	TO AVOID CONFLICTING REQUIREMENTS AND COSTLY MISTAKES, the specifier must edit (delete, substitute or add to the text).  The remaining paragraphs must be renumbered.

C.	DELETE FOR FINAL COPY: Notes to the Specifier, located between lines of asterisks; all [brackets], underlining, boldface, and italics within the paragraphs; and this page.  (Open Reveal Codes [alt F3] to do this accurately).

D.	To Edit “(Footer B)”: (Corel 8).  ENTIRE FOOTER SHOULD BE BOLDED.  Click in the footer and delete the “Project Name (ftr B)” text and replace it with the Name Of The Project (upper/lower case).  Replace date with current MM/YY (WITHOUT BRACKETS). 

E.	The Guide Specifications are intended to be continuously reviewed and revised.  User’s technical comments are appreciated.  Also, other related or similar specifications that are written “from scratch” that could benefit others, or other questions can be sent to NSTC A/E Group, ST-110 or call (303) 987-6851.

F.	DESIGN NOTES:

1.	DRAWING DATA REQUIRED:

REVISIONS OF THIS SECTION:
CSI format, editorial changes 10/99
Metric: Not Applicable
Technical Update: 8/00

SECTION 07620

SHEET METAL FLASHING AND TRIM

PART 1:  GENERAL

1.1	SUMMARY

A.	Section Includes:  Furnishing and installing galvanized sheet metal flashing and trim.

B.	Related Sections:

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LIST ITEMS OF WORK THAT MIGHT LOGICALLY BE FURNISHED AND INSTALLED IN THIS SECTION, BUT INSTEAD ARE SPECIFIED IN ANOTHER SECTION.  THIS ARTICLE IS RARELY REQUIRED.
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1.2	SUBMITTALS

A.	General:  Submittals shall be according to [Section 01009 - General Information and Requirements.] [and] [Section 01330 - Submittal Procedures] [and] [Section 01331 - Certificates.]

B.	Certificates of Conformance:  Submit [     ] copies of written certification from the supplier of the Contractor‑furnished sheet metal flashing and trim to be used on this project that they conform to the requirements of this specification section.

C.	Shop Drawings:  Submit [     ] copies of shop drawings for the sheet metal flashing and trim to be used on this project.  Shop drawings shall indicate thickness, dimensions, fastenings, and anchoring methods, expansion joints, and other provisions necessary for thermal expansion and contraction.  Sealed catalog cuts may be submitted for factory fabricated items.

1.3	QUALITY ASSURANCE

A.	Failure Criteria:  Not limited to the following:
1.	Rusting.
2.	Joint leaking.
3.	Metal pulling loose from subsurface.

1.4	DELIVERY, STORAGE, AND HANDLING

A.	Storage:  Crated materials shall not be uncrated until ready for use.  Store materials in dry, weather‑tight, ventilated areas until immediately before installation.

PART 2:  PRODUCTS

2.1	MATERIALS

A.	Zinc‑Coated (Galvanized) Sheet and Strip:  Shall be according to ASTM A 525.  Lengths of 8 or l0 feet.  Single pieces less than 8 feet long may be used to connect to factory fabricated corners, and at ends of runs.  Gauges shall be 24 or 26 as indicated on drawing details.  Also see Table 1.  The heavier gauge shall govern.  Metal shall be suitably factory‑marked to permit identification. 

B.	Nails:  Flat head, diamond point, bright, smooth finish zinc or cement coated.  Length shall be sufficient to penetrate backing materials 3/4 inch minimum.

C.	Solder:  Shall be according to ASTM B 486.

D.	Flux:  Consistent with solder, acid type.

PART 3:  EXECUTION

3.1	PREPARATION

A.	Subsurfaces:  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.  Installation of items not shown in detail or not covered by specifications shall meet the applicable requirements of the SMACNA Architectural Sheet Metal Manual.

3.2	INSTALLATION/APPLICATION

A.	Workmanship:  Fabricate sheet metal items to the gauge shown in Table I, and join multiple lengths of items together.  Install sheet metal work with lines, arises, and angles sharp and true.  Exposed surfaces shall be free from visible wave, warp, buckle and tool marks.  Exposed edges shall be folded back neatly to form a 1/2 inch hem on the concealed side.  Sheet metal exposed to the weather shall be watertight with provisions for expansion and contraction.

B.	Nailing:  Nailing of sheet metal shall be confined generally to sheet metal having a maximum width of 18 inches.   Nails shall be evenly spaced not more than 3 inches oc and approximately 1/2 inch from edge unless otherwise specified or indicated.  Face nailing will not be permitted.  

C.	Cleats:  Provide cleats for sheet metal 18 inches and over in width.  Space cleats evenly not more than 12 inches oc unless otherwise specified or indicated.  Unless otherwise specified, cleats shall be not less than 2 inches wide by 3 inches long and of the same material and thickness as the sheet metal being installed.  One end of the cleat shall be secured with two nails and the cleat folded back over the nailheads.  The other end shall be locked into the seam.  Cleats for soldered seams shall be pre‑tinned.

D.	Bolts, Rivets, and Screws:  Install where indicated or required.  Provide compatible washers where required to protect surface of sheet metal and to provide a watertight connection.

E.	Roof Protrusions:  Provide flashing in the angles formed where roof decks abut walls, curbs, ventilators, pipes, ducts, conduits, guywire anchors or other vertical surfaces projecting through the roof surface and wherever indicated and necessary to make the work watertight.  
1.	Pitch pockets will not be accepted.

F.	Seams:  Straight and uniform in width and height with no solder showing on the face.
1.	Flat‑lock:  Finish not less than 3/4 inch wide.
2.	Lap:  Finish soldered seams not less than one inch wide.  Overlap seams not soldered, not less than 3 inches.
3.	Loose‑lock Expansion:  Not less than 3 inches wide, and shall provide minimum one inch movement within the joint.  Joint shall be completely filled with the specified sealant, applied at not less than 1/8 inch thick bed.  Sealants are specified in Section 07920 ‑ Sealants and Caulking.
4.	Standing:  Not less than one inch high, double locked without solder.
5.	Flat:  Make seams in the direction of the flow.

G.	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.  Soldering shall follow immediately after application of the flux.  Upon completion of soldering the acid flux residue shall be thoroughly cleaned from the sheet metal with a solution of washing soda in water and rinsed with clean water.

H.	Base Flashing:  Where sloped roofs abut chimneys, curbs, walls or other vertical surfaces, the base flashings shall be laid in with each course of the roof covering, shingle fashion where practicable.  The flashing shall extend up vertical surfaces not less than 8 inches, and not less than 4 inches under the roof covering.  Where finish wall coverings form a counterflashing, the vertical leg of the flashing shall extend up behind the applied wall covering not less than 6 inches.  Flashing strips shall overlap the previously laid flashing not less than 3 inches; strips shall be fastened at their upper edge to the deck, with compatible largehead roofing nails.  End laps shall be soldered, except that provision shall be made for expansion and contraction.  At the upslope side of vertical surfaces extending through sloping roofs, the 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 4‑1/2 inches.  Flashings shall be installed and fitted so as to be completely weathertight.

I.	Counterflashing:  Except where indicated or specified otherwise, insert counterflashing in reglets located from 9 to 10 inches above roof decks and extend down vertical surfaces over upturned vertical leg of base flashings not less than 3 inches.  Exposed edges of counterflashings shall be folded 1/2 inch.  Where stepped counterflashings are required, they may be installed in short lengths or may be of the pre‑formed one‑piece type.  End laps in counterflashings shall be not less than 3 inches and shall be made weathertight with plastic cement.  Lengths of metal counterflashings shall not exceed 10 feet.  The flashings shall be formed to the required shapes before installation.  Corners shall be factory formed with joints not less than 12 inches from the angle.  Flashings shall be secured in the reglets with lead wedges spaced not to exceed 18 inches apart; on short runs, wedges shall be placed closer together.  Caulked‑type reglets or raked joints which receive counterflashing shall be filled with caulking compound.  Caulking is covered in Section 07920 ‑ Sealants and Caulking.  The concealed edge of counterflashings built into masonry or concrete walls shall be turned up not less than 1/4 inch and shall extend not less than 2 inches into the walls.  Counterflashing shall provide a spring action against base flashing.

J.	Caulked‑type Reglets:  Provide with rounded edges and metal strap brackets or other approved anchors for securing to the construction.  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 18 inches and shall be caulked full and solid with an approved sealant.

K.	Friction‑type Reglets:  Provide with flashing receiving slots not less than 5/8‑inch deep, one‑inch 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.

L.	Gravel Stops and Roof Edge Fascias:  Prefabricate in the shapes and sizes indicated and in lengths not less than 8 feet.  Extend flange at least 4 inches onto roof deck.  Provide prefabricated mitered corners for internal and external corners.  Install gravel stops and fascias after all plies of the roofing membrane have been applied, but before the flood coat of bitumen is applied.  Prime roof flange of gravel stops and fascias on both sides with an asphalt primer.  After primer has dried, set flange on top of the roofing felts in a 1/8 inch thick bed of plastic cement.  Nail flange securely to wood nailer with large‑head barbed‑shank roofing nails 1‑1/2 inches long spaced not more than 3 inches oc.  Roof shall cover flange with 9 inch wide strip of fiberglass mopped solidly in asphalt.
1.	Hook Strips:  The lower edge of fascias shall be hooked at least 3/4 inch 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 6 inches maximum oc.  Where fastening is made to concrete or masonry, screws spaced 12 inches oc shall be used and shall be driven in expansion shields set in the concrete or masonry.  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 1/16‑inch thick compatible spacer or washers.
2.	Joints:  Section ends of gravel stops and fascias shall be left open 1/4 inch and backed with a formed flashing plate, mechanically fastened in place and lapping each section end a minimum of 4 inches; set laps in plastic cement.  Face nailing will not be permitted.

M.	Metal Drip Edge:  Provide a metal drip, designed to allow water runoff to drip free of underlying construction, at eaves and rakes prior to the application of roofing shingles.  Apply directly on the wood deck at the eaves and over the underlay along the rakes, extend back from the edge of the deck not more than 3 inches and secure with compatible nails spaced not more than 10 inches oc along upper edge.

N.	Scuppers:  Line interior of scupper openings with sheet metal. The lining shall extend through and project outside of the wall to form a drip on the bottom edge and shall be formed to return not less than one inch against the face of the outside wall at the top and sides.  Outside edges shall be folded under 1/2 inch less than the perimeter of the scupper.  The top and sides of the lining on the roof deck side shall be joined to a closure flange by a locked and soldered joint.  The bottom edge shall be joined by a locked and soldered joint to the closure flange and, where required, shall be formed with a ridge to act as a gravel stop around the scupper inlet.  Surfaces to receive the scupper lining shall be primed and coated with bituminous plastic cement.

O.	Conductor Heads:  Fabricated of the same material as the downspouts.  Depth of top opening shall be equal to 2/3 of the width.  Outlet tubes shall not be less than 4 inches long.  All seams shall be flat‑locked soldered.  Where conductor heads are used in conjunction with scuppers, they shall be a minimum of 2 inches wider than the scupper, shall be attached to the wall with masonry fasteners, and shall be loose‑locked to the scupper drip.  Conductor heads shall have screens of the same material.  Screens shall be securely fastened to the heads.
P.	Splash Pans:  Install splash pans where downspouts discharge on roof surfaces and at other locations as indicated.  Unless otherwise shown, pans shall be not less than 24 inches long by 18 inches wide and shall have metal ribs across the bottom of the pan.  The sides of the pan shall be formed with vertical baffles not less than one inch high in the front and 4 inches high in the back of the pan, doubled over and formed continuous with horizontal roof flanges not less than 4 inches wide.  The rear flange of the pan shall be bent to contour of cant strip and shall extend up 6 inches under the side wall covering or to height of base flashing under counterflashing.  Pans and roof flanges shall be bedded in plastic bituminous cement and strip flashed.

Q.	Open Valley Flashing:  Valley flashing shall be free from longitudinal seams, shall extend not less than 6 inches under the roof covering on each side, and shall have a 1/2 inch fold on each side.  The sheets shall lap not less than 6 inches in the direction of flow and shall be secured to roofing construction with cleats attached to the fold on each side.  Tops of sheets shall be nailed to roof sheathing.  Cleats shall be spaced not more than 12 inches oc.  The exposed flashing shall be not less than 4 inches in width at the top and shall increase one inch in width for each additional 8 feet in length.  Where the slope of the valley is 4‑1/2 inches or less per foot, or the intersecting roofs are on different slopes, an inverted V‑joint one inch high, shall be provided along the centerline of the valley; and the edge of the valley sheets shall extend 8 inches under the roof covering on each side.  At Contractor's option, valley flashing for asphalt shingle roofs may be as specified in Section 07311 ‑ Asphalt Shingles.

R.	Eave Flashing:  One piece in width, applied in 8 to 10 feet lengths with expansion joints spaced as specified in paragraph T "Expansion Joints" below.  The upper edge of sheet shall have a 3/4 inch continuous fold to engage cleats spaced not more than 10 inches oc.  The upper edge of flashing shall be located not less than 18 inches from the outside face of the building, measured along the roof slope.  The lower edge shall be folded over and loose locked into a continuous edge strip on the fascia.  Where eave flashing intersects metal valley flashing it shall be secured with one inch flat locked joints with cleats that are 10 inches oc.  Eave flashing shall be placed over underlayment and in plastic bituminous cement as specified in Section 07311 ‑ Asphalt Shingles.

S.	Sheet Metal Coverings on Flat, Sloped or Curved Surfaces:  Except as specified or indicated otherwise, cover and flash all minor flat, sloped or curved surfaces such as crickets, bulkheads, dormers and small decks with metal sheets of the material used for flashing; maximum size of sheets, 16 x 18 inches.  Fasten sheets to sheathing with metal cleats.  Lock seams and solder.  Provide an underlayment of building paper for all sheet metal covering.

T.	Expansion Joints:  Expansion joints for roofs, walls, and floors shall be provided where indicated, shall conform to the requirements of Table I and be located at not more than 40 feet intervals, 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.   
1.	Roof Expansion Joints:  Shall consist of curb with wood nailing members on each side of joint, bituminous base flashing, metal counterflashing and metal joint cover.  Counterflashing shall be provided and installed as specified in paragraph "Counterflashing," except as follows:  The vertical leg of counterflashing shall be of suitable depth to enable forming into a horizontal continuous cleat.  The inner edge shall be secured to the nailing member.  The outer edge projection shall be not less than one inch for flashing on one side of the expansion joint and shall be less than the width of the expansion joint plus one inch for flashing on the other side of the joint.  The expansion joint cover shall be hooked over the projecting outer edges of counterflashing.  Roof joint shall be provided with a joint cover of the width indicated.  One edge of the joint cover shall be hooked and locked over the shorter projecting flange of the continuous cleat, and the other edge shall be hooked over and loose‑locked with the longer projecting flange.  Joints shall be as specified in Table II.
2.	Floor and Wall Expansion Joints:  Expansion joints in concrete and masonry walls and in floor slabs shall be a U‑shape configuration with extended flanges.  Cover plates for wall and floor joints are specified elsewhere.

U.	Interface with Other Products:  Metal surfaces in contact with mortar, concrete, or other masonry materials shall be painted with alkali‑resistant coatings such as heavy‑bodied bituminous paint.
1.	Requirements:  Sheet metal work shall be field painted in addition to that as required for the separation of dissimilar metals or for compliance with design requirements.  Painting shall be according to Section 09915 ‑ Exterior and Interior Painting.
2.	Prior to Painting:  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 marks.  Clean all exposed sheet metal work at completion of installation.

3.3	ADJUSTMENTS

A.	Requirements:  Scratches, abrasions and minor surface defects of finish may be repaired as approved.  Finish of repaired surfaces shall be uniform and free from scratches, blemishes, and from variations of color and surface texture.
	
TABLE I.  SHEET METAL GAUGES

                                          	Zinc
                                          	Coated
                                          	Steel
                                          	Gauge
                                           	        
                Building expansion joints
                   Cap...............      	  24

                   Flashings:
                      Base..............    	  24
                      Cap (Counter‑flashing)	  26
                      Eave..............    	  24
                   Gravel stops and fascias:
                      Sheets, smooth....    	  24
                   Cover plates.........    	  24

TABLE II.  SHEET METAL JOINTS

	Item		Zinc‑Coated Steel				Remarks

Joint cap for roof		1‑1/4 inch single lock,			‑‑
bldg. expansion joint 	standing seam, cleated

Flashings:
Base				1 inch flat locked, soldered	Fill with joint
                       	3 inches lap for expansion		sealant. See 	 joints  Section 07920- Sealants &
Caulking (1)

Cap‑in Reglet			3 inch lap					Seal groove with joint sealant asabove (2)

Reglets				Butt joint					Seal groove with joint sealant asabove (2)

Eave					1 inch flat locked, cleated 	Same as base	flashing

Stepped				3 inches lap					‑‑

Valley					6 inches lap, cleated			‑‑

Pitch Pockets			1 inch soldered lap			‑‑

(1)	Elastomeric flashing shall have 3‑inch lap with manufacturer's recommended sealant.

(2)	Polyvinylchloride type reglet shall be sealed with manufacturer's recommended sealant.

PART 4:  MEASUREMENT AND PAYMENT

4.1	METHOD OF MEASUREMENT

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WHEN A “LUMP SUM” CONTRACT IS USED, DELETE THE TITLE PART 4:  MEASUREMENT AND PAYMENT, AND BOTH ARTICLES FROM THIS SECTION.  MEASUREMENT AND PAYMENT WILL BE ADDRESSED IN PART 4 OF SECTION 01009 - GENERAL INFORMATION AND REQUIREMENTS OR SECTION 01010- SUMMARY OF WORK.  WHEN NOT A “LUMP SUM” CONTRACT, SELECT APPLICABLE PHRASES; USE THE “NO MEASUREMENT” PHRASE WHEN NONE OF THE PAY ITEMS IN THS SECTION ARE INCLUDED IN THE BID SCHEDULE.
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A.	Units: The work described in this section will [not be measured for payment]. [be measured for and paid for] [on a lump-sum basis].

4.2	BASIS OF PAYMENT

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WHEN NOT A “LUMP SUM” CONTRACT, SELECT APPLICABLE, SELECT APPLICABLE PHRASES; USE THE “NO DIRECT PAYMENT” PHRASE WHEN NONE OF THE PAY ITEMS IN THE SPECIFICATION ARE INCLUDED IN THE BID SCHEDULE.

WHEN NOT A “LUMP SUM” CONTRACT AND PAYMENT IS TO BE MADE UNDER THIS SECTION, SELECT APPLICABLE PAY ITEMS.  DO NOT CHANGE PAY ITEM NUMBER.  WHEN MORE THAN ONE DIAMETER OR GAUGE IS SPECIFIED FOR ANY PAY ITEM, LETTER SUFFIXES WILL BE ADDED AFTER THE PARENTHESIS OF THE ITEM NUMBER.  WHEN GOVERNMENT-FURNISHED PROPERTY IS SPECIFIED FOR PAY ITEMS, THE LETTER SUFFIX GF WILL BE ADDED AFTER THE PARENTHESIS OF THE ITEM NUMBER.
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A.	Payment: [No direct payment for the work described under this section will be made.  Consideration for this item shall be included in the bid price for other items of the Contract]. [Prices and payment will be full compensation for the work described in this section.  Payment will be made under:]

END OF SECTION

SHEET METAL FLASHING AND TRIM
Project Name (ftr B)	[8/00]
07620 -