A06_07540-Self-AdheredPVCRoofingSpec.docx

SECTION 07540

PVC THERMOPLASTIC ROOFING

(Fully Self-Adhered)

PART 1 GENERAL

PART 1 GENERAL

DESCRIPTION: The work of this section consists of furnishing and installing a polyvinyl chloride (PVC) thermoplastic membrane fully self-adhered on cover board on insulation on air barrier on sheathing complete with related flashings, expansion joints and performing such incidental or other work as may be necessitated by these operations.

PERFORMANCE REQUIREMENTS

General: Install a watertight thermoplastic membrane roofing and base flashing system with compatible components that will not permit the passage of liquid water and will withstand wind loads, thermally induced movement, and exposure to weather without failure. Conform to all Federal, State and Local codes for roof assembly and fire hazard requirements.

Factory Mutual Engineering & Research Corporation (FM): Provide thermoplastic membrane, base flashings, and component materials that meet requirements of FM 4450, FM 4454 and FM 4470 as part of a roofing system.

Roof assembly wind uplift requirements of I-90 in accordance with FM Construction Bulletin 1-28.

Underwriters Laboratories, Inc. (UL):

Class A Fire Hazard Classification.

SUBMITTALS

Manufacturer's Product Data: For each type of roofing product specified. Include date sheets and installation instructions to substantiate materials comply with requirements.

Shop Drawings: Include roof plans, sections, details and attachments to other work, for the following:

Base flashings, roof penetrations, equipment curbs and membrane terminations.

Fastening patterns of insulation, tapered insulation layout, including slopes.

Crickets, saddles and tapered edge strips, including slopes.

Manufacturer’s standard details as necessary to suit project requirements.

Samples for verification of the following products:

6-inch square of sheet membrane, illustrating the color of sheet and thickness.

6-inch squares of clad metal flashing, illustrating the color of sheet and thickness.

6-inch length of termination bar.

6-inch length of batten.

6-inch square of cover board.

6-inch square of roof insulation.

6-inch square of air barrier.

Insulation fasteners of each type, length and finish.

Sheathing fasteners of length and finish.

Fastener Pull-Out Test Results: Provide fastener/substrate test results as required by roofing system manufacturer.

Installer Certificates: Signed by the roofing system manufacturer certifying that Installer is approved, authorized, or licensed by manufacturer to install specified roofing system and is eligible to receive the standard roofing manufacturer’s warranty.

Manufacturer’s Certificates: Signed by the roofing system manufacturer certifying that the roofing system complies with requirements specified in 1.2 “Performance Requirements” and 1.4A “Quality Assurance” Articles including U. L. and F. M. compliance data and that the drawing details are acceptable to them for the deck and surfacing to which they are to be applied.

Copy of the manufacturer's standard roofing warranty stating obligations, remedies, limitations and exclusions of warranty.

Copy of the manufacturer's installation instructions, flashing and roof specifications.

Insulation manufacturer’s certification that the product is compatible with the roof system and meets specification requirements.

QUALITY ASSURANCE

Submit certification by the manufacturer of the system materials used that these Specifications are acceptable to them for the deck and surfacing to which they are to be applied.

If details for any manufacturer's systems proposed in these Specifications are not acceptable to the manufacturer, submit corresponding details proposed for the particular application, together with the manufacturer's reasons for not accepting the conditions depicted in these Specifications. No alternate details will be considered without evidence of valid objections on the part of the manufacturer to the Contract requirements.

Installer Qualifications: Engage an experienced installer to perform Work of this Section who has specialized in installing roofing similar to that required for this Project; who is approved, authorized, or licensed by the roofing system manufacturer to install manufacturer’s product; and who is eligible to receive the system roofing manufacturer’s warranty.

Inspection: Prior to, during and at completion of the installation, an inspection shall be made by a representative of the manufacturer in order to ascertain that the roofing system has been installed according to their published specifications, standards and details.

Follow “The ICC International Building Code”, most current publication, as published by the International Code Council, Inc. and applicable local and State amendments.

PRE-INSTALLATION CONFERENCE

Pre-installation Conference: Before installing roofing system, conduct conference at Project site. Notify Contracting Officer at least 5 days before conference.

Meet with Contracting Officer, roofing installer, roofing system manufacturer’s representative, and installers whose work interfaces with or affects roofing, including installer of roof accessories and roof mounted equipment.

Meeting Agenda:

Review methods and procedures related to roofing installation, including manufacturer’s written instructions.

Review loading limitations of deck during and after roofing.

Review flashings, special roofing details, roof penetrations, equipment curbs, and conditions of other construction that will affect roofing.

Review governing regulations and contract requirements for inspection.

Review temporary protection requirements for roofing system during and after installation.

Review roof observation and repair procedures after roofing installation.

Review safety requirements and means for compliance to OSHA regulations.

Contractor shall document proceedings, including corrective measures or actions required, and furnish copy of record to Contracting Officer.

DELIVERY, HANDLING AND STORAGE

Deliver all materials and store in their unopened and undamaged original packaging, bearing the manufacturer's name, related standards and any other specification or reference accepted as standard, in a clean, dry, protected location and within the temperature range required by the roofing system manufacturer.

When stored outdoors, stack materials on pallets or dunnage at least 4 inches above ground level and covered with ‘non-sweating” tarpaulins. Comply with material manufacturer’s written instructions for handling, storage, and protection during installation.

Provide continuous protection of materials from physical damage, from deterioration by sunlight, against wetting and moisture absorption, soiling and other sources. Store in a dry, well ventilated, watertight location to ensure no significant moisture pickup and maintain at a temperature not exceeding roofing system manufacturer’s written instructions. Remove any wet materials from jobsite and discard and legally dispose of liquid materials that can not be applied within its stated shelf life. In winter, store materials in heated location with a minimum 50°F temperature, remove only as needed for immediate use.

Store metal flashings and counterflashings in such a way as to prevent wrinkling, twisting, scratching and other damage. Do not leave unused sheet materials on the roof overnight or when the roofing work is not in progress unless protected from weather and moisture and unless maintained at a temperature exceeding 50°F. Adhesive storage must be between 40 to 80°F and in an area suitable for flammable storage.

Handle and store roofing materials and place equipment in a manner to avoid significant or permanent damage to deck or structural supporting members. Avoid stockpiling of materials on roofs without first obtaining approval from the Contracting Officer.

As determined by the Contracting Officer, remove all damaged material from job site and replace.

PROJECT CONDITIONS

Surfaces on which the roofing membrane system is to be applied shall be clean, smooth, dry, free of sharp edges, loose and foreign materials, oil and grease.

Do not begin installation until all defective conditions have been corrected.

All surface voids greater than 1/4-inch wide shall be properly filled with an acceptable fill material.

Weather Limitations: Proceed with roofing work only when existing and forecasted weather conditions permit roofing to be installed according to manufacturers’ written instructions and warranty requirements.

PROTECTION

The Contractor shall be responsible and liable for protection of all building elements not scheduled for work from any damage resulting from the work of this Section. The Contractor shall be responsible for maintaining the weather tightness of all portions of the roof during re-roofing operations. The Contractor shall be available on two hour’s notice, 24 hours a day for the duration of this work, to repair and prevent any and all leaks related to his work. The Contractor shall furnish the Contracting Officer with personal telephone number(s) and names of person(s) that will respond in the event of an emergency.

CLOSEOUT SUBMITTALS

Inspection Report: Copy of roofing system manufacturer’s inspection report of completed roof installation, including manufacturer’s punchlist.

WARRANTY

System Roofing Manufacturer’s Warranty: Upon completion of the work, submit a written and signed (15) fifteen year labor and material warranty, without monetary limitation, signed by roof system manufacturer agreeing to promptly repair leaks in the roof membrane and base flashing resulting from defects in materials or workmanship. The roofing manufacturer shall certify the performance of their products and the consistency of the properties of such products affecting their performance and the installation of the product for a period of 15 years from date of final acceptance. The Warranty shall contain no exclusions for random occurrences of ponding water.

Installer’s warranty: Submit the roofing Installer’s warranty, signed by Installer, covering all Work in this section, including membrane roofing, base flashing, fasteners, equipment curbs, and nailers, if any, against defects in materials and workmanship for a period of (2) two years following final acceptance of the Work.

PART 2 PRODUCTS

PART 2 PRODUCTS

PVC THERMOPLASTIC SINGLE-PLY ROOF SYSTEMS

Manufacturers and Systems: Membrane manufacturer shall have a minimum of 15 years of successful and proven performance with the same single-ply membrane without making adjustments, modifications or alterations to the chemical composition of the membrane. Subject to compliance with requirements, provide products by:

Sarnafil Inc., Canton, MA 02021-2898 Roof Membrane: G410 SA self-adhered fiberglass-reinforced PVC with lacquer coating, 60 mil nominal thickness.

Sheet Flashing Membrane: G410 fiberglass-reinforced PVC with lacquer coating, 60 mil nominal thickness.

Air Barrier: Vapor Retarder SA 31 self-adhered air barrier/vapor retarder, 31 mil nominal thickness.

Air Barrier Primer: Vapor Retarder Primer WB polymer emulsion water-based primer used to prime wood.

Clad Metal Flashing: Sarnaclad metal, 24-gauge galvanized G-90 steel, laminated with 20 mil PVC membrane on one side for heat-weldability.

Pre-Molded Flashing: Thermal-formed from non-reinforced PVC membrane for inside/outside corners and vent stack flashing.

Color: High Reflectivity White for materials on roof and parapet, Dark Grey for clad metal flashing drip edge exposed on fascia.

PVC Roof Membrane Uniform, self-adhered fiberglass-reinforced flexible sheet compounded from polyvinyl chloride (PVC) with plasticizers and modifiers, conforming to ASTM D4434.

Factory applied pressure-sensitive adhesive backing and siliconized polyethylene release liner.

Mechanical and Physical Properties:

Resistance to Static Puncture: 33 lbf minimum, ASTM D5602.

Resistance to Dynamic Puncture: 7.3 ft-lbf minimum, ASTM D5635.

Tensile Strength: 80 lbf/in. minimum, ASTM D751.

Elongation at Break: 250% M.D. minimum, 220% C.M.D. minimum, ASTM D751.

Linear Dimension Change: 0.02% maximum, ASTM D1204.

Tear Strength: 17.5 lbf minimum, ASTM D751.

Seam Strength: minimum 75% of tensile strength, ASTM D751.

Low-Temperature bend: -40°F, ASTM D2136.

SHEET FLASHING MATERIALS

Provide non-reinforced sheet membrane for flashing around curved objects as recommended by the roofing system manufacturer.

MEMBRANE ADHESIVE

Solvent-based adhesive for bonding central portion of sheet flashing membrane as recommended by the roofing system manufacturer.

AIR BARRIER

Tri-laminated woven polyethylene with a self-adhesive SBS modified bitumen backing and removable silicone release liner.

Mechanical and Physical Properties:

Resistance to Static Puncture: 90 lbf minimum, ASTM D5602.

Tensile Strength: 54 lbf/in minimum, ASTM D5147.

Ultimate Elongation: 33%, ASTM D5147.

Tear Resistance: 95 lbf minimum, ASTM D1970.

Peel Resistance: 5.4 lbf/in, ASTM D903.

Water Vapor Permeance: 0.03 perms, ASTM E96.

Air Flow Rate: <0.00006 cfm/sf, ASTM E2178.

SEALANT AND FILLERS

As recommended by the roofing system manufacturer.

COVER BOARD

Siliconizied gypsum with fiberglass-mat facers or gypsum cellulose fiber composite board, fire-tested hardboard, DensDeck Prime Roof Board as manufactured by Georgia Pacific Corp, or approved equal and meets or exceeds the following requirements.

Minimum Thickness – ½-inch Flame Spread (ASTM E84) – 0 Smoke Developed (ASTM E84) – 0 Water Vapor Permanence (ASTM E96) – greater than 23 perms Compressive Strength – 900 PSI minimum.

INSULATION

Board insulation shall be two layers of 2-inch minimum thickness for a total minimum thickness of 4 inches and have an average roof R-Value of 24 when using tapered insulation in combination with flat insulation.

Polyisocyanurate Board Insulation: Rigid, cellular polyisocyanurate thermal insulation with core formed by using blowing agents to comply with ASTM C1289-02 with Type II, Class 1 facer of glass-fiber mat on both surfaces and approved or provided by the membrane manufacturer. Boards shall be 4 feet by 4 feet as manufactured by Atlas Roofing Corp, Firestone Building Products or approved equal and meets or exceeds the following requirements.

R-Value (Long Tem Thermal Resistance) (CAN/ULC S770) – 6.0 min. per inch.

Compressive strength in thickness direction (ASTM D1621) – Grade 2 - 20 PSI minimum.

Dimensional stability (ASTM D2126) – less than 2% change in 7 days.

Moisture vapor transmission (ASTM E96) – less than 1.0 perm.

Tapered Insulation Board: Provide factory preformed, tapered insulation boards of the same insulation manufacturer where indicated for saddles, crickets, tapered edge strips and other insulating shapes as required. Fabricate to provide a positive ¼-inch per foot taper away from structures as shown. Minimum and maximum thickness of tapered board as recommended by roofing manufacturer. Tapered boards shall be 4 feet by 4 feet.

Drain Sumps: Provide factory preformed tapered insulation or equivalent drain sumps with ½-inch per foot taper around all drains.

SHEATHING

CDX Plywood, ½-inch thick (C side out), smooth-surfaced exterior grade plywood with exterior grade glue to replace 25% of the existing ½-inch OSB sheathing that is deteriorated, and as a second layer of sheathing for total sheathing thickness of 1-inch.

FASTENERS AND ANCHORS

The fasteners and plates/discs shall be provided by the roofing system manufacturer for the type of roof deck encountered, designed for fastening roof insulation and cover boards to substrate.

All fasteners, anchors, nails, straps, bars, etc. shall be of post-galvanized zinc or cadmium-plated steel, aluminum or stainless-steel complying with corrosion-resistance provisions in FM Approvals 4470. Mixing metal types and methods of contact shall be in such a manner as to avoid galvanic corrosion.

Wood: Fasteners shall be long enough to penetrate the wood by at least 1-inch and shall be approved for such use by the fastener manufacturer.

BOARD ANCHORAGE

Fasteners: FM approved and roofing manufacturer’s approved fasteners into nailable substrate.

WOOD BLOCKING AND NAILERS

All nailers and blocking material to be free of wane, shake, decay or checks, and pressure treated.

MISCELLANEOUS MEMBRANE ACCESSORIES

Provide miscellaneous accessories and materials recommended by roofing manufacturer for intended use.

Prefabricated expansion joint cover with foam tubing, galvanized metal nailing flanges and membrane welding tabs.

Prefabricated inside and outside corners made from membrane.

Prefabricated vent pipe flashing made from membrane.

Metal termination bars, aluminum, roll formed and prepunched.

Splash Mats fully adhered to roof membrane.

Other accessories as recommended by the roofing system manufacturer.

METAL FLASHING

Reuse existing metal flashing. Replace damaged portions with material that matches existing.

MISCELLANEOUS

Water Cut-Off: As approved by the roofing manufacturer.

PART 3 EXECUTION

PART 3 EXECUTION

SURFACE INSPECTION AND PREPARATION

Before commencing work, all surfaces shall be smooth, clean, dry, free of debris, flaws, sharp edges, loose and foreign material, oil and grease, and other substances detrimental to roofing installation according to roofing system manufacturer’s written instructions. All roof surfaces shall be free of water, ice, dew and snow.

Prevent materials from entering and clogging roof drains and conductors and from spilling or migrating onto surfaces of other construction. Remove roof drain plugs when no work is taking place or when rain is forecast.

The Contracting Officer’s Representative, together with the roofing contractor, shall inspect the deck condition.

Verify that roof openings, penetrations, plumbing and stack vents are in place, set and braced, and that roof drains are in the proper position.

Verify that wood blocking, parapet walls, curbs and nailers are securely anchored to the roof deck at roof penetrations and terminations and match the thickness of insulation required.

Verify that all curbs are properly secured to deck, are level and a minimum 8 inches above the finished roof.

Verify that surface roughness, flatness or slope of the deck surface complies with the roofing system manufacturer’s recommended installation instructions or as shown.

Verify that the work of other trades has been properly completed.

Verify that deck is securely fastened with no projecting fasteners and with no adjacent panels in excess of 1/16-inch out of plane and the substrate is suitable for adhered roofing system.

Do not proceed with installation until unsatisfactory conditions have been corrected.

INSTALLATION (GENERAL)

Perform roofing work on a continuous basis as surface and weather conditions allow.

Protect adjoining surfaces against any damage that could result from roofing installation.

Install only as much roofing as can be completed in one day. If weather conditions do not permit such completion, exposed areas shall be temporary weatherproofed to prevent any water or snow infiltration from damaging insulation or other materials already installed.

SHEATHING

Replace existing ½-inch OSB sheathing that is deteriorated (25% of entire roof area) with ½-inch CDX plywood. Notify Contracting Officer if more than 25% of existing sheathing should be replaced for potential contract modification.

Install second layer of ½-inch CDX (C side out), smooth-surfaced exterior grade plywood sheathing with exterior grade glue for total sheathing thickness of 1-inch. Stagger joints a minimum of 12 inches in both directions between first layer and second layer.

Secure sheathing to substrate (existing 2x8 rafters) with threaded mechanical fasteners (screws). Fastener spacing shall be at 12 inches on center. Fasteners shall be long enough to penetrate substrate (existing 2x8 rafters) by at least 1½-inch and shall be approved for such use by the fastener manufacturer.

AIR BARRIER

Install air barrier / vapor retarder on new plywood sheathing in accordance with manufacturer’s written instructions. Prime wood sheathing the same day as installation of air barrier. Extend air barrier up the perimeter and up deck penetrations. Lay out sheets so side laps overlap by 3-inches and end laps overlap by 6-inches. Peel back release liner, press onto substrate, and roll with a minimum 100 lb. roller.

WOOD NAILERS, CURBS AND FASCIA BOARDS

Install continuous treated wood nailers, and fascia boards at the perimeter of the entire roof and around roof projections and penetrations as shown.

Nailers and fascia boards shall be anchored to resist a minimum force of 300 pounds per linear foot in any direction.

Nailer fastener spacing shall be at 12 inches on center, 16 inches if necessary, to match the structural framing. Fasteners shall be staggered 1/3 the nailer width and installed within 6 inches of each end. Nailer attachment shall meet this requirement and that of the current Factory Mutual Loss Prevention Data Sheet 1-49. A ½-inch space shall be provided between adjacent lengths of nailers. Height of nailers shall match the surface level of the roof membrane or as shown.

Fascia board fastener spacing shall be at 24 inches on center with two fasteners as shown.

Treated wood curbs shall extend a minimum 8 inches above the finished roof. Fasteners shall be spaced to provide a design uplift resistance value of not less than 250 lbs./ft.

INSULATION

Comply with roofing system manufacturer’s written instructions for installing roof insulation. Insulation shall provide a smooth surface to accept the cover board.

Apply only as much insulation to the roof as can be covered the same day on the onset of inclement weather with roof membrane. Cut insulation to fit tight between projections and around penetrations. Tightly butt ends of adjacent insulation pieces together. Install no insulation less than 12 inches square. At the conclusion of each day’s work, seal exposed edges of the insulation. Cut and remove seal upon continuation of the work.

Install one or more layers of insulation under area of roofing to achieve required thickness. When overall insulation thickness is greater than 2 inches, install required thickness in 2 or more layers with joints of each succeeding layer staggered from joints of previous layer a minimum of 12 inches in each direction.

Install 4-feet by 4-feet boards in a continuous straight line with end joints staggered a minimum of 12 inches between rows, abutting edges and end between boards. Fill gaps exceeding ¼-inch with insulation. Cut and fit insulation within ¼-inch of nailers, projections and penetrations Install tapered insulation under roof area of roofing to conform to slopes indicated and to the approved shop drawings.

Taper boards a minimum distance of 18 inches back from roof drains for positive drainage. Trim surface of insulation where necessary at roof drains so completed surface is flush with drain.

Provide a smooth surface at cover board butt joints not exceeding 1/8-inch to accept the roof board.

Insulation shall be mechanically fastened to the substrate in a pattern according to the insulation board manufacturer’s Factory Mutual specified FM Windstorm Resistance Classification and the roof manufacturer’s recommendations.

COVER BOARD

Install 4 feet by 8 feet cover board with the 8-foot dimension perpendicular to the run of the membrane, over insulation with the long joints in continuous straight lines and with end joints staggered a minimum of 12 inches between rows. Stagger cover board from insulation joints a minimum of 6 inches in each direction. Butt board ends and edges tightly to adjacent boards. Use no cover board less than 4 square feet.

Fit cover board snug within ¼-inch of nailers, projections and penetrations and walls, to ends of all vertical surfaces, valleys and ridges. Cover board shall be cut at valleys, ridges and other areas where there exists a change in roof slope.

Do not install more cover board than can be covered with roof membrane or other protective membrane by end of day or the onset of inclement weather.

Provide a smooth surface at cover board butt joints not exceeding 1/8-inch to accept the roof membrane.

Secure cover board and insulation to substrate with threaded mechanical fasteners (screws) specifically designed and sized for the insulation thickness into the deck type shown.

BOARD ANCHORAGE

Fasteners Fasteners shall have a minimum penetration into the substrate as recommended by the fastener and roof manufacturer. Use fastener tool with a depth locator and torque-limiting attachment as recommended or supplied by fastener manufacturer to ensure proper installation.

Fasteners shall be in a pattern according to the cover board manufacturer’s Factory Mutual specified FM Windstorm Resistance Classification and the roof manufacturer’s recommendations.

ADHERED MEMBRANE INSTALLATION

Inspect the surface of the substrate prior to installation of the membrane. The substrate shall be clean, dry, free from debris and smooth with no surface roughness or contamination. Broken, delaminated, wet or damaged insulation boards or cover boards shall be removed and replaced. Unroll membrane and allow to relax for a minimum of 30 minutes.

Start first roll of membrane at and parallel with eave of the roof, valley or other low points on the roof. Overlap adjacent sheets to permit water and ice to flow over, towards the low point. Construct overlaps per manufacturer’s written instructions.

Stagger the roll ends to prevent adjacent welds from falling on top of one another. Membrane overlaps shall be in a shingle pattern to flow with water.

Fully adhere the roof membrane as per the roofing system manufacturer’s recommendations. Peel back release liner and press onto substrate. Roll membrane immediately afterwards with a minimum 100 lb. steel membrane roller.

HOT-AIR WELDING OF MEMBRANE OVERLAPS

All membrane overlaps (seams) shall be hot air welded. The membrane shall be clean and dry prior to hot-air welding. No adhesive shall be in the seam.

Field membrane overlaps for automatic machine-welding shall be 3” in width. A minimum of 4” wide overlap is required when hand-welding details.

Technicians intending to use hot-air welding equipment shall have successfully completed a training course provided by the roofing system manufacturer prior to welding.

Conform to Welding section of roofing system manufacturer’s Roofing Applicator Handbook for detailed installation instructions.

After installation, the Technician shall check all welded seams for continuity using a rounded screwdriver. 1-inch wide cross-section samples of welded seams shall be taken at least three times a day. Correct welds displaying failure from shearing of the membrane prior to separation of the weld. Each test cut shall be patched by the Applicator at no additional cost to the government.

MEMBRANE FLASHING INSTALLATION

All flashing shall be installed concurrently with the roof membrane as the job progresses. No temporary flashing shall be allowed without the prior approval of the Contracting Officer and roofing system manufacturer. If any water is allowed to enter under the newly completed roofing, the affected area shall be removed and replaced at the Contractor’s expense. Flashings shall be adhered to compatible, dry, smooth, non-asphaltic and solvent-resistant surfaces. Use caution to ensure adhesive fumes are not drawn into the building.

Over the properly installed and prepared substrate, apply adhesive using tools, means, methods and at a rate as recommended by the roofing system manufacturer. Protect adjacent completed roof membrane from adhesive smears by protecting the roof surface. Conform to minimum adhesive application temperatures set by the roofing system manufacturer. No adhesive shall be applied in seam areas that are to be welded.

Flashing overlaps on adjacent flashing and on roof membrane shall be in accordance to roofing system manufacturer’s requirements.

All flashings shall extend a minimum of 8 inches above roof level unless otherwise accepted by the Contracting Officer and roofing system manufacturer. Use pre-molded stack flashing at all vent pipes.

All flashing membranes shall be adhered to solvent resistant substrates. All interior and exterior corners and miters shall be cut and hot-air welded in place. Use pre-molded inside and outside corner flashing. No bitumen shall be in contact with the membrane.

All flashing membranes shall be mechanically fastened along the top edge through tin discs, washers or predrilled galvanized metal strip spaced at a maximum of 12 inches on center.

Conform to Typical Flashing Procedures section of roofing system manufacturer’s Roofing Applicator Handbook for detailed installation instructions.

VENTS (STACKS)

All vent stack flashings shall extend a minimum of 8 inches above roof level unless otherwise accepted by the Contracting Officer and roofing system manufacturer. Use pre-molded stack flashing at all vent, duct and flue pipes.

ROOF DRAINS

Provide a smooth transition from roof drain to membrane surface. Flash drains in compliance with manufacturer’s standard details and written installation instructions. Test all drains for proper flow and water-tightness. Correct all defects.

CLAD METAL FLASHING/EDGE FLASHING

All clad metal flashing shall be installed concurrently with the roof membrane as the job progresses. No temporary flashing shall be allowed without the prior approval of the Contracting Officer and roofing system manufacturer. If any water is allowed to enter under the newly completed roofing, the affected area shall be removed and replaced at the Contractor’s expense.

Fasten metal flashing according to roofing systems manufacturer’s standard details.

Flashing shall be installed to provide adequate resistance to bending and allow for normal thermal expansion and contraction.

Adjacent sheets of clad metal flashing shall be spaced ¼-inch apart. The end of the flashing shall be fastened 6 inches on center. The joint shall be covered with 2-inch wide aluminum tape. A 5-inch wide strip of flashing membrane that matches the color of the clad metal shall be hot-air welded over the joint.

METAL FLASHING

Metal details, fabrication practices and installation methods shall conform to the applicable requirements of the following:

Factory Mutual Loss Prevention Data Sheet 1-49 (latest edition) National Roofing Contractors Association (NRCA) Roofing and Waterproofing Manual latest edition.

Complete all metal work in conjunction with roofing and flashing so that a watertight condition exists daily.

Metal shall be installed to provide adequate resistance to bending and allow for normal thermal expansion and contraction.

Metal joints shall be watertight.

Metal flashing shall be securely fastened into solid wood blocking. Fasteners shall penetrate the wood nailer a minimum of 1-inch.

Counterflashing shall overlap base flashing at least 4 inches.

EXPANSION JOINTS

Flash all expansion joints in accordance with the roofing system manufacturer’s details. Ensure the expansion joint has sufficient material to expand to the widest point in expansion without causing undue stress on the expansion joint material.

TEMPORARY WATER CUT-OFF

All flashings shall be installed concurrently with the roof membrane in order to maintain a watertight condition as the work progresses. All temporary waterstops shall be constructed to provide a 100% watertight seal. The new membrane shall be carried into the waterstop. The waterstop shall be sealed to the deck and/or substrate so that water will not be allowed to travel under the new roofing. The edge of the membrane shall be sealed in a continuous heavy application of sealant. When work resumes, the contaminated membrane shall be cut out. All sealant, contaminated membrane, etc. shall be removed from the work area and properly disposed of off site. None of these materials shall be used in the new work If inclement weather occurs while a temporary waterstop is in place, the Contractor shall provide the labor necessary to monitor the situation to maintain a watertight condition.

If any water is allowed to enter under the newly completed roofing, the affected area shall be removed and replaced at the Contractor’s expense.

PROTECTION

Provide traffic ways, erect barriers, fences, guards, rails enclosures, chutes and the like to protect personnel, roofs and structures.

Provide a minimum 3/4-inch thick plywood plus a minimum of 1/2-inch recover board as temporary traffic ways for moving materials and equipment or when working around equipment on completed roofing.

Protect membrane roofing from damage and wear during remainder of construction period. When remaining construction will not affect or endanger roofing, inspect roofing for deterioration and damage with Contracting Officer prior to Substantial Completion.

CLEANING

Remove markings from finished surfaces using cleaning agents and procedures recommended by manufacturer of affected construction.

Repair or replace any defaced or disfigured finishes caused by work of this section.

FIELD CONTROL

Arrange for a final roof inspection with the roofing system manufacturer’s technical representative to inspect the roofing installation in the presence of the Contracting Officer’s Representative and submit report to the Contracting Officer.

Notify Contracting Officer and Contracting Officer Representative 4 calendar days minimum in advance of date and time of inspection.

Completed roof system shall be free of leaks and ponding water. No ponding water shall remain after 48 hours of measurable precipitation.

Correct deficiencies in or remove membrane roofing that does not comply with requirements, repair substrate, reinstall roofing, and repair base flashing to a condition free of damage and deterioration no later than the time of Substantial Completion and according to warranty requirements.

END OF SECTION