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	SECTION 07540
	THERMOPLASTIC MEMBRANE ROOFING (TPO)
	Copyright 2005 - 2009 ARCAT, Inc. - All rights reserved
	** NOTE TO SPECIFIER ** Dow Roofing Systems; single ply roofing systems. . This section is based on the products of Dow Roofing Systems, which is located at: 9 Sullivan Rd. Holyoke, MA 01040-2800 Toll Free Tel: 866-583-2583 Tel: 413-533-8100 Email: request info Web: www.dowroofingsystems.com [ Click Here ] for additional information. Dow Roofing Systems is a leading global provider of thermoplastic roofing membranes, and the inventors of reinforced thermoplastic polyolefin (TPO) roofing membrane. We manufacture and market some of the most technically advanced commercial roofing materials available on the market today. In fact, since the early 1980s, Dow has become the specified choice for building owners, architects, specifiers and roofing contractors in the world for both new construction and re-roofing applications. Since 1985, Dow Roofing Systems has been a leading industry advocate of the benefits associated with white reflective roofing. Dow has authored many articles on the benefits of white reflective roofing, and is a Charter member of the EPA Energy Star Roof Products Program, and also a member of the Cool Roof Rating Council. ** NOTE TO SPECIFIER ** This specification is intended for building roofs that have deck structures meeting guidelines herein and have no abnormally severe or unknown environmental exposures, e.g. coastal winds or certain chemicals, except as specifically authorized herein. Applications that involve severe exposures (ASCE Ground Roughness Category D) require review by Dow Roofing Systems Technical Review Dept. before any specification is valid (Reference ASCE Exposure Classification Chart). WARNING: Buildings operating with interior positive pressure at the deck require review by Dow Technical Review Dept. before any specification is valid.
	PART 1	GENERAL
	1.1	SECTION INCLUDES
	** NOTE TO SPECIFIER ** Delete items below not required for project.
		A.	Mechanically attached thermoplastic (TPO) roof membrane systems including insulation, roof edge and accessories.
		B.	Fully adhered thermoplastic (TPO) roof membrane systems including insulation, roof edge and accessories.
	1.2	RELATED SECTIONS
	** NOTE TO SPECIFIER ** Delete any sections below not relevant to this project; add others as required.
		A.	Section 06100 - Rough Carpentry: For nailers and roof assembly support.
		B.	Section 07620 - Sheet Metal and Trim.
	1.3	REFERENCES
	** NOTE TO SPECIFIER ** Delete references from the list below that are not actually required by the text of the edited section.
		A.	ASTM International (ASTM):
			1.	ASTM C 578 - Standard Specification for Rigid Cellular Polystyrene Thermal Insulation.
			2.	ASTM C 1177 - Standard Specification for Glass Mat Gypsum Substrate for Use as Sheathing.
			3.	ASTM C 1289 - Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board.
			4.	ASTM D 6878 - Standard Specification for Thermoplastic Polyolefin Based Sheet Roofing.
		B.	American Society of Civil Engineers (ASCE): ASCE 7 - Minimum Design Loads for Buildings and Other Structures.
		C.	FM Global (FMG) 4470 - Approval Standard for Class 1 Roof Covers.
		D.	Underwriters Laboratory UL 790 - Standard Test Methods for Fire Tests of Roof Coverings.
		E.	International Code Council (ICC):
			1.	International Building Code (IBC).
	1.4	PERFORMANCE REQUIREMENTS
		A.	General: Provide installed roofing membrane and flashings that remain watertight; do not permit the passage of water; and resist specified uplift pressures, thermally induced movement and exposure to weather without failure.
		B.	Material Compatibility: Provide roofing materials that are compatible with one another under service and application required, as demonstrated by roofing membrane manufacturer based on testing and field experience.
		C.	Thermal Performance:
			1.	Roof system will achieve a minimum R value not less than ____.
		D.	Wind Uplift Performance:
	** NOTE TO SPECIFIER ** Delete wind uplift performance criteria options not required for project. If selecting an option that has blanks, insert values into blank spaces.
			1.	Roof System designed to meet manufacturers warranty issuance requirements.
			2.	Roof system designed and successfully tested by a qualified testing and inspecting agency to withstand uplift forces as calculated using the current version of ASCE 7.
			3.	Roof system designed and successfully tested by a qualified testing and inspecting agency to withstand uplift forces listed below:
				a.	Corner Uplift Pressure: ___ lbf./sq.ft.
				b.	Perimeter Uplift Pressure: ___ lbf./sq.ft.
				c.	Field of Roof Uplift Pressure: ___ lbf./sq.ft.
			4.	Roof system designed and successfully tested to FM Global (FMG) 4470 Approval Standard for Class 1 Roof Covers, which meet the calculated design pressure requirements of the roofing system as stipulated in FM Global Property Loss Prevention Data Sheets 1-28.
			5.	Roof system is designed to achieve a FM 1-___ wind uplift rating.
		E.	Fire Resistance Performance:
	** NOTE TO SPECIFIER ** Delete fire rating classes not required for project.
			1.	Roof system will achieve a UL Class A rating when tested in accordance with UL-790.
			2.	Roof system will achieve a UL Class B rating when tested in accordance with UL-790.
			3.	Roof system will achieve a UL Class C rating when tested in accordance with UL-790.
		F.	Drainage: Provide a roof system with positive drainage where all standing water dissipates within 48 hours after precipitation ends.
		G.	Building Codes: Roof system will meet the requirements of all federal, state and local code bodies having jurisdiction.
	1.5	SUBMITTALS
		A.	Submit under provisions of Section 01300.
		B.	Product Data:, including:
			1.	Manufacturer's data sheets on each product to be used.
			2.	Preparation instructions and recommendations.
			3.	Storage and handling requirements and recommendations.
			4.	Installation methods.
		C.	Samples for Verification for the following products:
			1.	Manufacturer's standard sample size of sheet roofing of color specified.
			2.	Manufacturer's standard sample size of roof insulation.
			3.	Manufacturer's standard sample size of walkway pads or rolls.
			4.	Fasteners of each type and finish used for complete roofing installation.
		D.	Shop Drawings:
			1.	Outline and size of the roof, location and type of penetrations, perimeter and penetration flashing detail references to manufacture's standard. Details which do not conform to roofing manufacturer's standards shall be identified with separate approval from roofing manufacturer. Details to be employed on the project shall be approved by roofing manufacturer.
		E.	Warranty Certification:
			1.	Submit warranty certification from manufacturer of approval of project design and intent to issue warranty.
	** NOTE TO SPECIFIER ** Delete if not required for mechanically fastened roof systems over gypsum, cementitious woodfiber decks ('Tectum') and light-gauge metal panel roofs.
			2.	Fastener pull tests from an independent testing agency shall be approved by the roofing manufacturer.
	1.6	QUALITY ASSURANCE
	** NOTE TO SPECIFIER ** Include manufacturer qualifications. Delete if not required.
		A.	Manufacturer Qualifications: Manufacturer with a minimum of ten years experience in the manufacturing of single-ply heat weldable membranes.
		B.	Installer Qualifications: Roofing contractor shall be authorized by roofing system manufacturer to install assembly. Provide letter on manufacturer's letterhead of authorized status of Contractor.
		C.	Manufacturer Certificates: Signed by roofing manufacturer certifying that roofing system complies with requirements specified in "Performance Requirements" Article.
		D.	Energy Performance: Provide roofing system that is listed on the DOE's ENERGY STAR "Roof Products Qualified Product List" for low-slope roof applications.
	1.7	DELIVERY, STORAGE, AND HANDLING
		A.	Pallets may be stored on the ground in a secure area. If placed on the roof, the load shall not exceed the structural capacity of the deck or crushing resistance of the insulation.
		B.	Packaging shall bear the UL and FM labels.
		C.	Store products in manufacturer's unopened packaging until ready for installation.
		D.	Store and dispose of solvent-based materials, and materials used with solvent-based materials, in accordance with requirements of local authorities having jurisdiction.
	1.8	PROJECT CONDITIONS
		A.	Maintain environmental conditions (temperature, humidity, and ventilation) within limits recommended by manufacturer for optimum results. Do not install products under environmental conditions outside manufacturer's absolute limits.
	1.9	WARRANTY
		A.	A manufacturer's representative shall inspect the installation for compliance with manufacturer's standards upon completion of the roofing system.
			1.	Deviations or changes from the contract specification shall have written approval from the roofing manufacturer, for presentation to Architect at completion of roofing system.
	** NOTE TO SPECIFIER ** Manufacturer permits selection of single warranty option listed below (B, C, D, E or F). Delete all but the warranty option required for project.
		B.	Limited Material Only Warranty: Shall be issued upon acceptance of the roofing system installation.
	** NOTE TO SPECIFIER ** Delete warranty period not required.
			1.	Five (5) year period.
			2.	Ten (10) year period.
			3.	Fifteen (15) year period.
	** NOTE TO SPECIFIER ** Refer to roofing manufacturer's additional requirements for 20-year Warranty Systems. Delete if warranty type not required or available for specified system.
			4.	Twenty (20) year period.
		C.	Standard Material and Labor Warranty: Shall be issued upon acceptance of the roofing system installation.
	** NOTE TO SPECIFIER ** Delete warranty periods not required.
			1.	Five (5) year period that covers wind damage up to 70 mph (112.6 k/hr).
			2.	Ten (10) year period that covers wind damage up to 70 mph (112.6 k/hr).
			3.	Fifteen (15) year period that covers wind damage up to 70 mph (112.6 k/hr).
	** NOTE TO SPECIFIER ** Refer roofing manufacturer's additional requirements for 20-year Warranty Systems. Delete if warranty type not required or available for specified system.
			4.	Twenty (20) year period that covers wind damage up to 70 mph (112.6 k/hr).
		D.	No Dollar Limit (NDL) Material and Labor Warranty: Shall be issued upon acceptance of the roofing system installation.
	** NOTE TO SPECIFIER ** Delete warranty periods not required.
			1.	Five (5) year period that covers wind damage up to 70 mph (112.6 k/hr).
			2.	Ten (10) year period that covers wind damage up to 70 mph (112.6 k/hr).
			3.	Fifteen (15) year period that covers wind damage up to 70 mph (112.6 k/hr).
	** NOTE TO SPECIFIER ** Refer roofing manufacturer's additional requirements for 20-year Warranty Systems. Delete if warranty type not required or available for specified system.
			4.	Twenty (20) year period that covers wind damage up to 70 mph (112.6 k/hr).
	**NOTE TO SPECIFIER** Total System Warranties require all products for installation to be purchased through roofing membrane manufacturer.
		E.	Standard Total System Warranty: Shall be issued upon acceptance of the roofing system installation.
	** NOTE TO SPECIFIER ** Delete warranty periods not required.
			1.	Five (5) year period that covers wind damage up to 70 mph (112.6 k/hr).
			2.	Ten (10) year period that covers wind damage up to 70 mph (112.6 k/hr).
			3.	Fifteen (15) year period that covers wind damage up to 70 mph (112.6 k/hr).
	** NOTE TO SPECIFIER ** Refer roofing manufacturer's additional requirements for 20-year Warranty Systems. Delete if warranty type not required or available for specified system.
			4.	Twenty (20) year period that covers wind damage up to 70 mph (112.6 k/hr).
		F.	No Dollar Limit (NDL) Total System Warranty: Shall be issued upon acceptance of the roofing system installation.
	** NOTE TO SPECIFIER ** Delete warranty periods not required.
			1.	Ten (10) year period that covers wind damage up to 70 mph (112.6 k/hr).
			2.	Fifteen (15) year period that covers wind damage up to 70 mph (112.6 k/hr).
	** NOTE TO SPECIFIER ** Refer roofing manufacturer's additional requirements for 20-year Warranty Systems. Delete if warranty type not required or available for specified system.
			3.	Twenty (20) year period that covers wind damage up to 70 mph (112.6 k/hr).
	PART 2	PRODUCTS
	2.1	MANUFACTURERS
		A.	Acceptable Manufacturer: Dow Roofing Systems, which is located at: 9 Sullivan Rd. ; Holyoke, MA 01040-2800; Toll Free Tel: 866-583-2583; Tel: 413-533-8100; Email: request info; Web: www.dowroofingsystems.com
		B.	Requests for substitutions will be considered in accordance with provisions of Section 01600. All substitutions must meet the quality assurance requirements as specified in sections 1.4 and 1.6 above.
	2.2	MATERIALS
		A.	Roofing Membrane shall be manufactured by Dow Roofing Systems with the following properties:
	** NOTE TO SPECIFIER ** Delete membrane type not required.
			1.	Membrane Type:
				a.	Tiempo™+ 2000 TPO.
	** NOTE TO SPECIFIER ** Contact Dow Technical Review Dept. for more information regarding color options and membrane size. Delete thickness not required.
			2.	Membrane Thickness:
				a.	45 mil.
				b.	60 mil.
				c.	80 mil.
			3.	Color:
				a.	Energy Efficient White.
		B.	Flashings Membrane:
			1.	Shall be 0.045 inch (1.14 mm) or 0.060 inch (1.52mm) thick reinforced membrane for walls and curbs regardless of roof cover sheet thickness.
			2.	Shall be .060 inch (1.52 mm)-thick unsupported membrane for field-fabricated details used for making field flashings that require higher extensibility than is allowed with scrim-reinforced membrane. Typical application examples include inside and outside corners, vent stacks, and other penetrations.
	** NOTE TO SPECIFIER ** Insulation or protection boards other than those specifically referenced must be accepted in writing by roofing manufacturer.
		C.	Insulation shall be Dow Roofing Systems approved insulation with the following properties:
	**NOTE TO SPECIFIER ** Delete insulation types and strengths not required.
			1.	TERMICO™ Polyisocyanurate Insulation: Closed-cell HCFC Free polyisocyanurate foam core and integrally laminated to heavy non-asphaltic fiber-reinforced felt facers. Available in flat stock and tapered panels.
	**NOTE TO SPECIFIER ** Delete Compressive strength not required.
				a.	Compressive strength: 20 psi (138 kPa).
				b.	Compressive strength: 25 psi (172 kPa).
			2.	TERMICO™ ISO 3000: Closed-cell HCFC Free polyisocyanurate foam core manufactured using ACUltra and integrally laminated to heavy coated-glass facers.
	**NOTE TO SPECIFIER ** Delete Compressive strength not required.
				a.	Compressive strength: 20 psi (138 kPa).
				b.	Compressive strength: 25 psi (172 kPa).
	**NOTE TO SPECIFIER ** Refer to manufacturer's Technical Data Sheets for additional information. Delete if not required.
			3.	STYROFOAM™ Extruded Polystyrene (XPS): Extruded polystyrene closed-cell foam panel that meets ASTM C-578, Standard Specification for Rigid Cellular Polystyrene Thermal Insulation.
	**NOTE TO SPECIFIER ** Delete products not required.
				a.	DECKMATE™ Plus: Rigid, closed cell type extruded polystyrene board with integral high density skin.
				b.	DECKMATE™ Plus FA: Extruded polystyrene board with planed surface for use with insulation adhesive.
				c.	RECOVERMATE™ CR: Extruded polystyrene fanfolded foam board with poly-coated kraft facers.
			4.	Dow Expanded Polystyrene (EPS): ASTM C 578 expanded polystyrene thermal rigid board insulation with a minimum density of 1.25 lb/cf (20 kg/cm).
	**NOTE TO SPECIFIER ** Refer to Dow Product Specifications Data Sheets for additional information. Delete if not required.
		D.	Cover Board:
	**NOTE TO SPECIFIER ** Refer to manufacturer's Technical Data Sheets for additional information. Delete cover board not required.
			1.	DensDeck® Roof Boards: G-P Gypsum Corporation 1/4 inch (6 mm) DensDeck® Roof Board. Glass mat faced gypsum with specially treated gypsum core that resists moisture and mold growth.
			2.	DensDeck® Roof Boards: G-P Gypsum Corporation 1/2 inch (12 mm) DensDeck® Roof Board. Glass mat faced gypsum with specially treated gypsum core that resists moisture and mold growth.
			3.	DensDeck® Roof Boards: G-P Gypsum Corporation 5/8 inch (16 mm) DensDeck® Roof Board. Glass mat faced gypsum with specially treated gypsum core that resists moisture
	**NOTE TO SPECIFIER ** DensDeck® Prime Roof Board is used for fully adhered applications.
			4.	DensDeck® Roof Boards: G-P Gypsum Corporation 1/4 inch (6 mm) DensDeck® Prime Roof Board. Glass mat faced gypsum with specially treated gypsum core and non-asphaltic, highly filled proprietary heat-cured coating on one side.
			5.	DensDeck® Roof Boards: G-P Gypsum Corporation 1/2 inch (12 mm) DensDeck® Prime Roof Board. Glass mat faced gypsum with specially treated gypsum core and non-asphaltic, highly filled proprietary heat-cured coating on one side.
			6.	DensDeck® Roof Boards: G-P Gypsum Corporation 5/8 inch (16 mm) DensDeck® Prime Roof Board. Glass mat faced gypsum with specially treated gypsum core and non-asphaltic, highly filled proprietary heat-cured coating on one side.
		E.	Adhesives, Primers, Caulk, Sealants:
	**NOTE TO SPECIFIER ** Delete products not required.
			1.	Dow 2000 Membrane Adhesives: Are designed for bonding TIEMPO™+ 2000 membranes to wood, metal, masonry and approved roof insulation board surfaces.
				a.	Dow 2000 Membrane Adhesive (Solvent Based).
				b.	Dow 2000 Membrane Adhesive (Low- VOC).
			2.	Dow 2000 Multi-Purpose Sealant: Designed to be used as a water cutoff mastic, sealant to top off pitch boxes, and an exterior grade caulk for metal work.
			3.	Dow 2000 Edge Sealant: A solvent based caulk developed to seal exposed cut edges of reinforced membranes.
			4.	Dow 2000 Insulation Adhesives.
				a.	Dow 2000 Insulation Adhesive (2 Part Urethane): Is a two-part, polyurethane low rise foam that is applied in ribbons with appropriate dispensing equipment.
				b.	INSTA STIK™ Quik Set Insulation Adhesive: Single component polyurethane insulation adhesive dispensed from a portable, disposable, pre-pressurized container requiring no external power.
			5.	Dow 2000 Membrane Cleaner: A surface cleaner for use with TIEMPO™+ 2000 membranes that have become dirty or contaminated prior to heat welding.
	**NOTE TO SPECIFIER ** Delete products not required.
		F.	Edge Metal Systems:
			1.	Dow Edge: Shall consist of a heavy formed aluminum base rail with a snap-on cover installed around the outside edge of buildings.
			2.	Dow Fascia: An extruded aluminum bar with a snap-on cover installed around the outside edge of buildings.
	**NOTE TO SPECIFIER ** If fascia is being used choose ' a,' ' b' or ' c' below and delete products not required.
				a.	Standard Fascia.
				b.	HG Fascia.
				c.	Extended Fascia.
				d.	Canted Fascia.
			3.	Dow Systems 200.
			4.	Dow Drip Edge.
			5.	Dow Coping.
		G.	Termination Bar: Dow 2000 Aluminum Termination Bar shall be fastened 6 inches (152 mm) o.c.
	**NOTE TO SPECIFIER ** Delete products not required.
		H.	Accessories:
			1.	Dow 2000 TPO Pipe Boots/Vent Gloves- Pre-fabricated Pipe Boots, shall be used for vent stacks and pipes 1 inch (25 mm) to 6 inch (152 mm) in diameter.
			2.	Dow 2000 TPO Universal Inside/Outside Corners.
			3.	Dow 2000 T-Joint Patch.
			4.	Dow 2000 TPO Walkway Roll- Dow Tiempo+ Walkway Roll is heat welded to the membrane where indicated or required for warranty.
			5.	Dow 2000 Flashing Tape and Dow 2000 Primer Kit shall be used for stripping-in gravel stop and drip edge metal.
			6.	Slip Sheet- Medium to heavy weight (6 oz or heavier) non-woven polyester fabric.
	**NOTE TO SPECIFIER ** Refer to roofing manufacturer's technical manual to select appropriate fastener/plate combination and approved fastening rates. The Dow Roofing Systems Technical Manual can be found at www.dowroofingsystems.com . Delete fasteners not required for project
		I.	Fasteners: Fastener type, length and pull-out resistance shall be approved by roofing manufacturer and supplied by roofing manufacturer. Fastener shall be selected to provide proper attachment for the calculated design pressures, project deck type and proposed membrane sheet attachment.
			1.	Dow 2000 Fastener #14: For insulation attachment. Use with Dow 2000 Insulation Plate, 3 inch.
			2.	Dow 2000 Fastener #12: For insulation attachment. Use with Dow 2000 Insulation Plate, 3 inch.
			3.	Dow 2000 Fastener #21: For membrane attachment featuring a drill point and a deep buttress single lead thread. Use with Dow 2000 Metal Seam Plate 3 inch.
			4.	Dow 2000 Fastener #15: For membrane attachment. Use with Dow 2000 Metal Seam Plate 2-3/8 inch.
			5.	Dow 2000 Insulation Plate 3 inch.
			6.	Dow 2000 Metal Seam Plate 3 inch.
			7.	Dow 2000 Metal Seam Plate 2-3/8 inch.
			8.	Dow 2000 Insulation Fastener (PIF): For insulation attachment and is comprised of a #12 fastener with a 3 inch polymer locking plate.
			9.	Dow 2000 Preassembled Fastener #15 is for membrane attachment and is comprised of a Dow 2000 Fastener #15 and a Dow 2000 Metal Seam Plate 2-3/8 inch.
			10.	Dow 2000 Concrete Fastener: Non-threaded hammer-in fastener for membrane and insulation attachment.
			11.	Dow 2000 Masonry Anchor: Hammer-in type expansion fastener for securing termination bars.
	PART 3	EXECUTION
	3.1	EXAMINATION
		A.	Do not begin installation until substrates have been properly prepared.
		B.	Nailers and blocking shall be installed level, true to line and elevation, secured to roof structure to resist roof installation and service conditions. Refer to Section 06100.
	** NOTE TO SPECIFIER** Reroofing: Use #2 or better wood treated for rot resistance. Creosote and asphaltic preservatives are not acceptable. New roofing: As specified by Architect. A pressure preservative treated wood nailer is recommended. Effective perimeter attachment must be achieved per details. All construction: Nailer shall be anchored with a suitable fastener for the application having a minimum withdrawal resistance of 100 lb (45 kg), staggered 6 inches (152 mm) o.c. within 8 ft (2.4 m) of an outside corner and 12 inches (304 mm) o.c. along other perimeter areas. All construction: Nailer thickness shall be chosen to match the top surface of adjacent construction 1/4 inch (6 mm). This permissible variation shall not contribute to ponding.
		C.	If substrate preparation is the responsibility of another installer, notify Architect of unsatisfactory preparation before proceeding.
	3.2	PREPARATION
	** NOTE TO SPECIFIER** Consideration should be given in the project design to potential safety problems that can precipitate from the smooth surface characteristic of the TIEMPO™+ 2000 sheet. The membrane surface becomes slippery when wet. If access to roof is required, walkway surfaces are high recommended. In northern climates, sliding snow could create a hazard below and adjacent to the perimeter if a retarding system is not installed on roofs with slopes greater than 2-inch per foot (170 mm/m). ** NOTE TO SPECIFIER** Job Specification and retrofit preparation should always include provisions to ensure positive drainage in all areas. Good roofing practice does not permit uncontrolled, uncollected drainage over the edge of a roof. ** NOTE TO SPECIFIER** For buildings with canopies or large wall openings, e.g. hangar doors and truck entrances or docks, which are subject to positive pressurization from wind, or from air handling systems, consult Dow Roofing Technical Staff for suitability of application and possible design enhancement requirements.
		A.	Adhesives, solvents, and caulks as indicated are potentially flammable and/or toxic. Follow precautions indicated on container or packaging labels.
		B.	Surfaces to be bonded shall be dry, clean and free of debris. Suitable surfaces are usually considered to be smooth: solid masonry, wood and metal, plus insulation boards fastened per the specific manufacturer's recommendations for receiving adhered roofing membranes.
		C.	All fasteners should be installed with a depth-sensing screw gun to prevent over driving or under driving.
		D.	Block off or shut down positive pressure building ventilation systems during application to prevent sheet from billowing during application.
		E.	Verify all rooftop mechanical units are to have their condensation lines piped to drains, or off the roof.
		F.	Grease shall not be allowed to accumulate on the roof. If rooftop grease units do not receive continual maintenance they are to have an approved grease contaminant system specified.
	** NOTE TO SPECIFIER ** Vapor retarder: Is not required for protection of Dow Roofing System membrane. As a guideline, the National Roofing Contractors Association states, "...vapor retarders should be considered for use when both of two conditions are anticipated: (1) the outside mean, average January temperature is below 40 degree F (4.4 degree C), and (2) the expected winter, interior relative humidity is 45 percent or greater." ** NOTE TO SPECIFIER ** Steel deck, wood plank and lightweight cementitious decks: Shall be covered with an approved insulation mechanically fastened or adhered to the deck with Dow approved product (INSULATION ADHESIVES NOT APPROVED FOR STEEL ROOF DECKS) with Dow approved product (Reference Appendix MA-B, Approved Insulation List & Fastening Rates). Reference roofing membrane manufacturer's technical manual for insulation list and fastening rates. Polystyrene boards may require a thermal barrier underlayment over steel decks. Consult manufacturer and local building codes. Delete deck type not required.
		G.	Steel Deck:
			1.	Shall be covered with an approved insulation mechanically fastened to the deck.
		H.	Wood Plank:
			1.	Shall be covered with an approved insulation mechanically fastened or adhered to the deck.
		I.	Lightweight Cementitious Decks:
			1.	Shall be covered with an approved insulation mechanically fastened or adhered to the deck.
	** NOTE TO SPECIFIER ** Concrete, plywood, or flat sheet-metal surface: Thickness, structural grade, fastening, and fire resistance requirements should meet the requirements and recommendations of applicable building codes and the APA and are the responsibility of the owner and the installer.
		J.	Concrete Deck:
			1.	Concrete shall be cured, and prepared smooth with dust removed.
			2.	Shall be covered with an approved insulation mechanically fastened or adhered to the deck.
		K.	Plywood Deck:
			1.	Plywood must be exterior grade with an A or B finish side up and with no joints gapped greater than 1/4 inch (6 mm).
			2.	Shall be covered with an approved insulation mechanically fastened or adhered to the deck.
	** NOTE TO SPECIFIER** Reroofing over existing roof: The specifier and/or applicator shall determine the condition of the existing roof. Significantly deteriorated decking must be repaired or replaced, as appropriate. Wet materials (containing free moisture that would evaporate if exposed to atmosphere) must be found and replaced.
		L.	Reroofing Over Existing Roof:
			1.	Condition of the existing roof must be appropriate for reroofing application. Significantly deteriorated decking must be repaired or replaced, as appropriate. Wet materials (containing free moisture that would evaporate if exposed to atmosphere) must be found and replaced
			2.	Surface shall be dry, smooth and even, blisters cut, and loose aggregate removed.
				a.	Installation of approved insulation or cover board shall comply with manufacturer's standards
				b.	Metal seam plates and appropriate fastener shall be used to anchor the membrane to the deck at perimeters and penetrations.
		M.	Ponding at the membrane level shall be corrected by improved drainage design as required to eliminate "birdbathing" to less than 4 square feet (.37 square meters), less than 1/2 inch (13 mm) deep areas.
		N.	Prepare surfaces using the methods recommended by the manufacturer for achieving the best result for the substrate under the project conditions.
	3.3	INSTALLATION
		A.	Provide temporary ballast in partially completed sections to control wind effects during construction.
	** NOTE TO SPECIFIER ** Certain insulation types such as polystyrene are not compatible with coal tar pitch. Contact insulation manufacturer for recommendations. In regard to attachment, compatibility and spanning metal flutes, the manufacturers' instructions or specifications shall determine the suitability for an application, subject to acceptance roofing membrane manufacturer. Delete if not required.
		B.	Insulation Installation:
	** NOTE TO SPECIFIER ** Delete if not required.
			1.	Mechanical Attachment: Insulation boards shall be attached with manufacturer approved insulation plates and fasteners.
	** NOTE TO SPECIFIER ** INSULATION ADHESIVES ARE NOT APPROVED FOR ADHERING SIRECTLY TO STEEL ROOF DECKS). Delete if not required.
			2.	Adhered Insulation with Approved Adhesive: Installation requirements of the adhesive and insulation manufacturer shall be followed. Insulation boards shall be secured sufficiently to conform to the substrate surface geometry.
	** NOTE TO SPECIFIER ** Delete if not required.
			3.	Tapered Insulation:
				a.	Tapered edge strip of high density fiberboard shall be used to provide a smooth transition to the flat areas.
				b.	Insulation boards shall be installed with the longest dimension perpendicular to the direction of the membrane seams whenever possible and installed with end joints staggered. Boards will be butted as closely as possible with no gaps over 1/4 inch (6 mm) and secured to substrate.
	** NOTE TO SPECIFIER ** Delete following section for mechanically attached membrane if fully adhered membrane installation is specified.
		C.	TIEMPO™+ 2000 TPO Mechanically Attached Membrane Installation:
			1.	Perimeter Sheets: defined as TIEMPO™+ 2000 membrane with a maximum sheet width of 5-ft.
			2.	Perimeter area shall be defined as follows: The extent of perimeter and corner enhancement is based on the smaller value of either 40 percent of building elevation or 10 percent of the least horizontal dimension. Perimeter/corner enhancement can never be less than 4 percent of the least horizontal plan dimension, of 3-ft.
	** NOTE TO SPECIFIER ** For Metal Roof Retrofit applications, perimeter and corner fastening enhancement is achieved by decreasing the distance between lap seam fasteners (along the purlin courses) rather than decreasing the distance between fastener rows (sheet width) as in a traditional mechanically attached installation. Delete if metal retrofit not required.
			3.	Perimeter/Corner Enhancement: Perimeter sheets shall be installed at all exposed building perimeters. Perimeter sheets shall be laid out in a pattern approved by membrane manufacturer. Provide fasteners at spacing required by roofing membrane manufacturer to comply with wind uplift requirements. Appropriate fastener and plate combination shall be installed along the edge of the membrane through the insulation and into the roof deck.
			4.	Field sheets: Fasten field sheets with approved fasteners which meet the wind uplift requirements of the roofing system as specified in section 1.4.D. Ensure that the deck materials and grade have been identified and that the proper fastener and plate are installed at the needed spacing to achieve the design as specified. Fastener and plate combination shall be installed along the leading edge of the membrane through the insulation and roof metal into the structural decking. Adjacent rolls of membrane shall overlap the fastened edge of the installed membrane.
			5.	Lap Splice: Membrane shall be overlapped and hot-air welded without any contaminants (adhesive, dirt, debris, etc.) in the seam.
				a.	The entire lap edge shall be probed with an approved seam probing tool after the seam has cooled completely to verify seam consistency.
				b.	Cut edges shall be caulked by applying sealant.
			6.	Perimeter fastening: At perimeters that are to receive a gravel stop or metal edging, membrane shall be brought over the outside edge and terminated 12 inches (610 mm) o.c to wood nailers. Membrane shall be fastened at other terminations by using fasteners and seam plates.
	** NOTE TO SPECIFIER ** Delete following section for fully adhered membrane if mechanically attached membrane installation is specified.
		D.	TIEMPO™+ 2000 TPO Fully Adhered Membrane Installation:
			1.	Perimeter area shall be defined as follows: the extent of perimeter and corner enhancement is based on the smaller value of either 40 percent of building elevation or 10 percent of the least horizontal dimension. Perimeter/corner enhancement can never be less than 4 percent of the least horizontal plan dimension, of 36 inches (914 mm).
			2.	Ensure substrate is installed in conformance to meet the wind uplift requirements of the roofing system as specified in section 1.4D.
			3.	For roofs with interior drainage, start with first sheet centered on drain valley. Fold sheet so that the bottom side half of the full length of sheet is exposed.
			4.	Summer ambient conditions may dictate adhering smaller areas of membrane at a time to prevent drying of adhesive. Adhesives should never be cut or extended. Outside ambient air temperature must be a minimum 40 degrees F (4.5 degrees C) and rising.
			5.	Apply a 100 percent continuous coat of Dow 2000 Membrane Adhesive (Solvent Based) or Dow 2000 Membrane Adhesive (Low VOC) to the exposed bottom side of the sheet and the corresponding substrate area.
			6.	Adhesive coverage should be 60 square ft. per gallon for coating substrate and membrane. Cold weather, inconsistent spreading, and rough or porous substrates (i.e. DensDeck® or concrete) will consume more adhesive. Membrane must have 100 percent adhesion to the approved substrate. Several peel tests should be performed daily to ensure proper adhesion of membrane to substrate.
			7.	Adhesive must be spread out by roller as necessary to achieve 100 percent coverage on the substrate and membrane. Adhesive should never be broomed or mopped and must not be cut or extended.
			8.	If adhesive has been contaminated by blowing dust, moisture, walking in it, etc. it should be allowed to completely dry (no longer tacky) and new adhesive applied to both surfaces.
			9.	Allow adhesive to dry until tacky and does not string or stick to a dry finger. When sufficiently dry, carefully unfold the glued portion of the membrane in a rolling motion onto the glued substrate surface, avoiding any wrinkles or air pockets. Immediately roll the adhered area using a weighted pressure roller (such as a water-filled lawn roller). Applying pressure with a roller is required to promote full contact of the membrane with adhesive.
			10.	Repeat the procedure for the other half of the sheet.
			11.	For roofs with edge drainage, start at the low edge with the first sheet and follow the procedure described in the preceding paragraphs. Starting membrane application at high points may be necessary if the substrate type prevents effective tie-offs or if it is not possible to complete roof area to the high point (ridge) by the end of the day.
			12.	Lay out the second sheet with a minimum 2 inches (51 mm) overlap on the edge of the first sheet. Perform lap splice. After splice has cooled, completely expose the bottom side of the second sheet by folding back along the splice. Apply adhesive evenly to both underside of membrane and substrate surface, allow to dry to the point where the adhesive is tacky, and carefully turn membrane back onto glued substrate surface avoiding any wrinkles or air pockets. Roll surface using a weighted pressure roller applying pressure to promote full contract. Repeat procedure for each sheet proceeding across roof.
			13.	At perimeters that are to receive a gravel stop or metal edging, the membrane must be brought over the outside edge and terminated at 12 inches (305 mm) o.c. unless otherwise stated in the appropriate detail.
			14.	Membrane must be mechanically attached 12 inches (305 mm) o.c. at all perimeters and at any penetration that has a dimension of 24 inches (610 mm) or greater with Dow fasteners and plates.
			15.	Lap splice: Membrane shall be overlapped and hot-air welded without any contaminants (adhesive, dirt, debris, etc.) prevalent in the seam.
				a.	Hot-air welding: An automatic hot-air welder and hand-held welder which are functionally in top condition are a necessity for Dow applications. Small work and repairs can be completed efficiently with the hand-held welders, however, hand-held welders are not a recommended means of field seaming.
				b.	The entire lap edge must be probed with approved seam probing tool (i.e. Sears cotter pin extractor) after it has cooled completely to verify seam consistency. Probing before the seam area has cooled will damage the membrane. In addition, destructive tests should be performed daily on a 3 inches (76 mm) wide area of seam weld to verify sufficient peel strength. A properly welded seam will have membrane delamination from scrim prior to weld failure. Destructive tests on welds should be done for the first seam of the day, first seam after the robot welder has been allowed to cool down, and after any extreme changes in weather conditions.
		E.	Flashing Installation: Perimeters, curbs, vents, expansion joints, drains, and other details shall be flashed. Under no circumstances shall flashings cover weep holes or any form of through-wall drainage.
			1.	Pipe flashings shall be installed in accordance with manufacturer's detail. Do not flash to lead.
			2.	Expansion joints shall be installed according to manufacturer's detail.
			3.	Roof drains shall be installed in accordance with manufacturer's detail.
	** NOTE TO SPECIFIER ** Delete if not required.
			4.	In reroofing, old drains must be cleaned or replaced as needed for clamping detail. All bolts shall be properly secured to supply 100 percent continuous compression of the clamping ring. Remove old leads and packings. Field seams shall not be run through drains. Prefabricated sleeve insert with a clamping ring and backflow seal are acceptable.
		F.	Metal Work Installation:
			1.	Metal work shall be installed in a manner that prevents damage from buckling or wind.
			2.	Metal work shall be sealed and waterproofed.
		G.	Overnight Seal/Temporary Water Stop Installation:
			1.	Water stop shall be made by a sealant method approved by manufacturer.
			2.	Roofing contractor shall coordinate installation to ensure the system is made watertight at the end of each work day.
	** NOTE TO SPECIFIER ** Delete if not required.
		H.	Roof Walkways Installation: When regular and routine roof traffic is anticipated (for example, to service rooftop units), walkway roll is required to be installed over the membrane.
			1.	Membrane shall be clean and dry. Remove any visible dirt and debris.
			2.	Position walkway roll and cut to desired length.
			3.	Walkway shall not cover seams. Walkway roll shall be kept a minimum of 2 inches from the edge of the seam on the bottom sheet of the completed lap and a minimum of 6 inches (152 mm) from the edge of the seam when located on the top sheet of a completed lap.
			4.	Fully weld perimeter of walkway roll to the membrane following standard welding procedures.
	3.4	INSPECTION
		A.	Destructive tests shall be performed daily on a 3 inches (76 mm) wide area of seam weld to verify sufficient peel strength. Verify seam strength and correct procedures and seams that do not provide watertight durable construction.
			1.	A properly welded seam will have membrane delamination from scrim prior to weld failure.
			2.	Additional destructive tests on welds shall be conducted for the first seam of the day, the first seam after the robot welder has been allowed to cool down, and after any extreme changes in weather conditions.
		B.	Upon completion of the installation, an inspection will be performed by a representative of the roofing manufacturer to ascertain that the roofing membrane system has been installed according to approved specifications and details. Upon approval of the project, a Warranty shall be written.
	3.5	PROTECTION
		A.	Protect installed products until completion of project.
		B.	Touch-up, repair or replace damaged products before Substantial Completion.
	END OF SECTION