MDVL182124 - Coating_over_Metal_Substrate_Spec.pdf

Section 07560

Liquid-Applied Roofing

Roof Coating Over Metal Substrate

ROOF COATING OVER METAL SUBSTRATE SPECIFICATION

SECTION 07560

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PART 1 GENERAL

1.1 SECTION INCLUDES

A. This specification is intended to outline the requirements for application of roof coatings, in conjunction with the appropriate product technical data sheets, over approved roof substrates in acceptable condition. Specific addenda address each surface at the end of this guide specification.

1.2 RELATED SECTIONS

A. Section 06100: Rough Carpentry: Roof blocking installation and requirements.

B. Section 07620: Sheet Metal Flashing and Trim: Metal flashing and counter flashing installation and requirements.

C. Section 15430: Plumbing Specialties: roof drains, scuppers, gutters and downspout installation and requirements.

1.3 REFERENCES

A. Factory Mutual (FM Global) - Approval Guide.

1. Factory Mutual Standard 4470 - Approval Standard for Class 1 Roof Covers.

B. Underwriters Laboratories (UL) - Roofing Systems and Materials Guide (TGFU R1306).

C. ASTM International (ASTM) - Annual Book of ASTM Standards.

1. ASTM D 1079 - Standard Terminology Relating to Roofing, Waterproofing, and Bituminous Materials.

2. ASTM D 1653 - Standard Test Methods for Water Vapor Transmission of Organic Coating Films.

3. ASTM D 4263 - Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method.

4. ASTM D 4798 / D4798M – 1- Standard Practice for Accelerated Weathering Test Conditions and Procedures for Bituminous Materials (Xenon-Arc Method).

5. ASTM D 6083 - Standard Specification for Liquid Applied Acrylic Coating Used in Roofing

6. ASTM E 96 - Standard Test Methods for Water Vapor Transmission of Materials.

7. ASTM E 108 - Standard Test Methods for Fire Tests of Roof Coverings.

8. ASTM G 26 - Practice for Operating Light-Exposure Apparatus (Xenon-Arc Type)

With and Without Water for Exposure of Nonmetallic Materials.

9. ASTM G 53 - Practice for Operating Light- and Water-Exposure Apparatus

(Fluorescent UV-Condensation Type) for Exposure of Nonmetallic Materials.

D. Sheet Metal and Air Conditioning Contractors National Association, 1nc. (SMACNA) -

Architectural Sheet Metal Manual.

E. National Roofing Contractors Association (NRCA).

F. American Society of Civil Engineers (ASCE).

1. ASCE 7 - Minimum Design Loads for Buildings and Other Structures.

1.4 DEFINITIONS

A. Roofing Terminology: Refer to ASTM D1079 and the glossary of the National Roofing

Contractors Association (NRCA) Roofing and Waterproofing Manual for definitions of roofing terms related to this section.

1.5 SYSTEM DESCRIPTION

A. The roof coating work includes roofing, flashing and reinforcing of joints and junctions, and roof accessories integrally related to roof installation.

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B. Final determination of the fitness of the system, or its components, for any given metal roof must be made by a representative of the roof coating system manufacturer.

C. Provide an installed roofing membrane and base flashing system that does not permit the passage of water, and will withstand the design pressures calculated in accordance with the current revision of ASCE 7.

D. Manufacturer shall provide all primary roofing materials that are physically and chemically compatible when installed in accordance with manufacturers current application requirements.

1.6 SUBMITTALS

A. Submit under provisions of Section 01300.

B. Product Data:

1. Provide product data sheets for each type of product indicated in this section.

C. Shop Drawings:

1. Provide manufacturers standard details and approved shop drawings for the system specified.

1.7 QUALITY ASSURANCE

A. Manufacturer Qualifications: Contractor shall provide a roofing system that meets or exceeds the criteria listed in this section.

B. Installer Minimum Qualifications:

1. Installing contractor shall be approved by the manufacturer for the selected system installation.

C. Source Limitations: Components listed shall be provided by a single manufacturer or approved by the primary roofing manufacturer.

1.8 PRE-INSTALLATION CONFERENCE

A. Prior to scheduled commencement of the roofing installation and associated work, conduct a meeting at the project site with the installer, Government, manufacturer’s representative and any other persons directly involved with the performance of the work.

The installer shall record conference discussions to include decisions, agreements, and open issues and furnish copies of recorded discussions to each attending party. The primary purpose of the meeting is to review foreseeable methods and procedures related to roofing work.

1. Tour representative areas of roofing substrates to inspect and discuss conditions of substrate, penetrations and other preparatory work to be performed.

2. Review roof coating requirements (manufacturer’s specifications, detail drawings and the Contract Documents).

3. Review required submittals, both completed and in progress.

4. Review and finalize the construction schedule related to roofing work, and verify availability of materials, installer's personnel, equipment and facilities needed to consistently make progress and avoid delays.

5. Review required inspection(s), testing, and certifying, and material usage accounting procedures. Review forecasted weather conditions.

6. Establish procedures for coping with unfavorable conditions, including the possibility of temporary roofing work.

1.9 REGULATORY REQUIREMENTS

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A. Work shall be performed in a safe, professional manner, conforming to federal, state and local codes.

B. UL Listing: Provide roof coating and component materials which have been evaluated by Underwriters Laboratories for flame-spread, and are listed in the "Underwriters Laboratory Roofing Materials and Systems Directory" for Class A construction over existing metal or other non-combustible roofing (Flame-spread shall pass ASTM E-108 and/or UL 790). Provide roof covering materials bearing UL approval marking on the container. This indicates that the material has been subjected to UL's examination, test procedures and follow-up inspection service.

1.10 DELIVERY, STORAGE, AND HANDLING

A. Store and handle roof coating materials in a manner that will ensure there is no possibility of contamination.

B. Store in a dry, well ventilated, weather tight location at temperatures between 50°F

(10°C) and 90°F (32°C) until the products are ready to be applied (keep from freezing).

Do not stack material pallets more than two (2) high.

C. Do not subject existing roof to unnecessary loading of stockpiled materials.

D. Store and dispose of solvent-based materials, and materials used with solvent-based materials, in accordance with requirements of local authorities having jurisdiction.

1.11 PROJECT CONDITIONS

A. Weather:

1. Proceed with roofing only when existing and forecasted weather conditions permit.

2. Ambient temperatures shall be above 50°F (10°C) when applying water based adhesives.

B. Proceed with roofing work only when existing and forecasted weather conditions will permit work to be performed in accordance with manufacturer’s recommendations and guarantee requirements as follows:

1. Do not begin work if precipitation is expected within twenty-four hours of application, or if temperatures are expected to fall below 50°F (10°C) during the duration of the job.

2. Upper temperature restriction (both air and substrate) for application of products is 110°F (43°C). If substrate temperatures exceed 110°F (43°C), products shall be applied during cooler periods of the day. If this is not practical, the substrate shall be cooled with water, and then products applied just after the water has flashed-off.

3. No moisture may be present when applying roof coating products. Taking into consideration the curing properties allow for sufficient daylight hours necessary for curing of materials.

4. Alternative work plans, materials, or more lenient manufacturer’s recommendations for environmental conditions may be submitted for Government review prior to commencement of work.

1.12 WARRANTY

A. NDL Roof Guarantee: Manufacturers standard form, without money limitation, in which manufacture agrees to repair leaks through the coating products on the roof caused by manufacturing defects, natural deterioration, or workmanship in applying the roofing system.

1. Warranty Duration:

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a. Twenty (20) Years Labor and Material with NO DOLLAR LIMIT

PART 2 PRODUCTS

2.1 MANUFACTURERS

A. GAF, Roof Mate HT, 3.5 Gal/Sq (29 mil DFT) B. American Weather Star, MET-A-GARD+, 3.0 Gal/Sq (25 mil DFT) C. Tropical Roofing Products, 901HS, 3.5 Gal/Sq (29 mil DFT) D. The approved manufacturers’ list is not all-inclusive but is provided to demonstrate typical expectations of performance and quality.

E. Substitutions: Will be considered with equal or greater performance characteristics and warranty. For all parties protection, substitutions should be requested prior to bidding. It is the responsibility of the Contractor to provide sufficient information and data to the Government when requesting substitution for an expedient determination.

F. Requests for substitutions should be submitted at least seven (7) business days prior to bidding to allow ample review and response time.

2.2 COATINGS

A. Roof Coating Over Metal Substrate System: A high tensile water-based acrylic top coat utilizing the latest advances in acrylic technology for roof areas subject to heavy maintenance traffic, severe weather conditions, chemical fallout, etc. High tensile emulsion polymers are combined with reinforcing pigments and nonmigrating fire retardants for superior physical properties, durability, weatherproofing, dirt and mildew resistance, ultraviolet resistance, and fire retardancy.

1. Application Rate: As specified by manufacturer for 20 year NDL warranty (1.0 gallon per 100 square feet per coat minimum).

2. Application Method: Airless sprayer, brush, or roller. Method shall be determined as necessary to provide (1) a consistent thickness equaling or exceeding the requirements, and (2) a uniform appearance and neat installation.

3. Application Temperature (air, surface): 50°F (10° C) - 110°F (43°C); deviations must by approved prior by manufacturer AND Government.

4. Dry time: As specified by manufacturer.

5. Color: Government shall have access to manufacturer’s standard color options

(multiple options to include tans, grays, and white at minimum; custom or “premium” colors not required) for top coats. Contractor shall submit physical samples for color selection.

2.3 FLASHINGS, FABRIC AND BULKING AGENTS

A. Installer shall provide the Government a plan via submittal for use of various roof coating system components such as flashing compounds, fabrics, and tapes. The submittal shall identify which components are proposed for use in each scenario for the referenced project in accordance with manufacturer’s recommendations.

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B. Roof Coating System Flashing Compound: A high volume solids for low shrinkage providing increased tensile strength and elongation on problem roof areas. It is ideally suited for sealing mechanical fasteners and horizontal seams on metal roofs, as well as around flashings, drains and protrusions.

1. Application Rate: 2.0 gal per 200 linear feet with a 6 inch width, 2 coats typically required.

2. Application Method: Putty Knife, spatula and stiff bristle brush.

3. Application Temperature (ambient): minimum 50°F (10°C), or as recommended.

4. Dry Time: 1-4 hours depending on application thickness

5. Clean-up: Water before curing.

C. Roof Coating System Flashing Fabric: tough, non-woven, stitch-bonded, heat-set polyester designed for roofing and flashing applications of all types.

D. Roof Coating System Seam Tape: A polymer-backed woven polyester reinforcing fabric designed for application to a wide range of substrates where additional strength is required over seams, splits, transitions, protrusions, etc.

1. Temperature Limits for Service -30°F to 180°F (-35°C to 82°C)

2. Bond Time: Initial bond is immediate; full bond requires approximately 24 hours.

2.4 PRIMERS AND SEALANTS

A. Primer: Installer or manufacturer shall provide, as a recommended and integral part of their roof coating system, a water-based, medium viscosity material, providing corrosion protection, flash rust resistance and enhanced adhesion over steel, aluminum and galvanized metal surfaces. The primer shall be a single component, premium quality exterior acrylic latex primer that is blister and stain resistant, permanently flexible, highly durable, and exhibit excellent corrosion resistance over metal substrates and alkali resistance over concrete and masonry.

1. Application Rate: As recommended by manufacturer, but not less than 0.33 gal per 100 ft2, depending on substrate, surface and porosity.

2. Application Method: Airless sprayer or brush.

3. Application Temperature (air, surface): 50°F (10°C) – 110°F (43°C), or as recommended.

4. Dry Time: 75°F (24°C), 50% relative humidity: 20-30 minutes.

B. Sealant: Installer or manufacturer shall provide, as a recommended and integral part of their roof coating system, a solvent-based synthetic elastomeric compound designed to line and waterproof exterior surfaces typically found in metal buildings capable of withstanding ponding water.

1. Application Rate: As recommended by manufacturer.

2. Application Method: Roller or airless sprayer.

3. Application Temperature (air, surface): 32°F (0°C) - 120°F (49°C), or as recommended.

4. Dry Time: 75° F (24°C), 50% relative humidity: Approximately 24 hours.

C. Cleaning Concentrate: Manufacturer or installer shall provide a highly effective cleaning agent that, when combined with water, penetrates the existing coating or substrate and allows contaminants to be flushed from the surface. It must be non-toxic and leave no

07560 08/17 pollutants or contaminating by-products to damage the environment. Used for the proper cleaning of existing elastomeric coating on roofs, metal surfaces, concrete and masonry substrates, as well as uncoated roof, deck and wall surfaces.

1. Application Rate: As recommended by manufacturer.

2. Application Method: Low pressure sprayer or broom.

2.5 EQUIPMENT

A. Airless Sprayer and Accessories: As recommended by manufacturer.

PART 3 EXECUTION

3.1 SUBSTRATE CONDITIONS

A. Installer shall verify adherence to the substrate with a field peel adhesion test, achieving a minimum result of 2.0 pounds per linear inch (PLI) [0.36 kilograms per linear centimeter (kg/cm)]. Questionable substrates shall be directed to the manufacturer’s technical team for resolution.

B. Follow the manufacturer’s substrate preparation guidance prior to any coating system application. Clarify any discrepancies between this specification and the manufacturer’s recommendations prior to any activity.

3.2 SYSTEM APPLICATION

A. PREPARATION OF SUBSTRATE

1. Preparation of the Roof substrate is the responsibility of the Installer. Installer shall address and correct all of the conditions listed in this section. Examine substrates to receive new roofing. Do not proceed with installation of the roof coating system until unsatisfactory conditions have been corrected in a manner acceptable to the manufacturer.

2. Installation of sheet metal crickets: Sheet metal crickets shall be installed according to manufacturer's specifications as necessary (minimum 26 gauge (0.455 mm) metal -heavier gauge required for larger crickets) on the high side of all curb units. Vertical ribs shall be cut a minimum of 2 inches (51 mm) from the cricket to allow both the cricket flanges to mount flush to the metal panel and facilitate water drainage. Cut vertical ribs shall then be treated in the same fashion as a void larger than a 1/4 inch (6 mm). New crickets shall be "sealed" by placing a continuous bead of approved sealant under the flanges before they are mechanically attached to the curb unit and metal roof panel. Then, the cricket flanges shall be stitch-screwed to the curb unit and metal roof panel while the sealant is still wet using fasteners. This procedure shall apply to installation of all new crickets and curbs.

3. Treatment of Ponding Water Areas: Installer shall make every effort to mechanically eliminate all ponding water areas on the roof prior to application of roof coating system products. Ponding water is defined as water which does not properly drain and remains on the roof surface for more than 48 hours after precipitation stops.

4. Repair of Dented / Damaged Panels: Installer shall repair dented and/or damaged metal roof panels. Dents shall be mechanically removed to the maximum extent possible. If ribs are broken, Installer shall cover the broken rib area with a sheet metal cap. Sheet metal rib caps shall be sealed to the roof by applying roof coating system flashing over the entire broken rib area to be capped prior to attaching the cap with fasteners. Then, approved flashing shall be used to seal all the newly created rib cap seams and fasteners. Roof panels that are severely damaged shall be removed and replaced prior to application of roof coating system products.

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5. Re-tightening and Replacement of Fasteners: All fasteners shall be re-tightened, secured or replaced, as necessary. All stripped fasteners shall be replaced with larger diameter fasteners, and the area re-secured by adding a new fastener next to the one that was stripped. All missing fasteners shall be replaced. The fastening pattern may require modification to facilitate the proper installation of the system.

6. Thorough Cleaning / Removal of Existing Paints and Coatings: Metal substrate shall be Power washed with water or by other pre-approved method. A minimum working pressure of 3,000 psi (20 MPa) shall be used to remove all delaminating paint and coatings dirt, dust, and waste products (oil, oil-based roof cements, solvents, grease, animal fats, etc.). A Roto-spray tip is required to expedite metal panel cleaning. All existing silicone-based sealants shall be completely removed from roof substrate prior to application of roof coating system products. When encountering roof substrates that have living organisms such as algae, mold or fungus, an approved solution shall be used to kill and remove these organisms during the roof cleaning.

7. Treatment of Residual Asphalt: Installer shall make every effort to remove asphaltic roofing elements. Removal efforts shall include use of methods such as pressure washing, scrapers, wire brushes, electric drill wire-wheels, or other similar tools.

Residual asphalt is defined as asphaltic material remaining after the exercise of all required removal efforts, and exists when there is asphaltic material greater in thickness than 3 mils (.08 mm) over an area greater than 1 square foot (0.1 m2).

Residual asphalt shall be primed with an approved primer.

8. Treatment of Rust Areas: Remove all loose, flaking or powdery rust by wire brushing if it has not been removed during the pressure washing. Use appropriate primer prior to coating. Roof panels which are corroded to the point where holes are present shall be replaced.

9. Priming of Pre-Finished Metal Panels: Where roof panel surfaces are known or suspected to contain Kynar-500, other fluoropolymers or silicone, test patches shall be prepared with and without the use of an approved primer. Based on test patch adhesion results, Installer shall apply primer on pre-finished metal panels per specifications.

10. Pitch Pans: For most situations, pitch pans shall be capped with sheet metal so they can be sealed with roof coating system products.

11. Neoprene Pipe Boots: Refer to manufacturer for recommendations for neoprene boot installations prior to flashing work being performed for certain types of pipe penetrations. Neoprene boots shall first be sealed to the roof using a bead of an approved sealant prior to mechanical attachment with fasteners.

12. Open Ridge Vents: Open ridge vents (as shown in detail drawings) may begin to corrode on the inside, and over time, may leak. Sheet metal caps shall be installed when leaks are suspected from the vents, or the vents may be replaced if necessary.

Installation of a cap on the ridge vent will prevent water entry while allowing air to continue to flow through the vent. Do not seal weep holes on the vents. Inadequate roof ventilation may cause blistering of the roof coating due to inside air "blowing-out" through roof panel seams. When this condition occurs, it may not allow for proper curing of the roof coating system material which may cause blisters.

13. Deteriorated Seams/Cracks: Repair all delaminated or open seams using method acceptable to the manufacturer.

A. FLASHING APPLICATION

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1. After completion of substrate preparation, all flashing details, horizontal seams, penetrations and curbs shall be 3-course flashed with roof system flashing fabric embedded in flashing compound in accordance with the manufacturer’s detail drawings. Flashing shall be feathered at the edges to ensure that water flows over the various flashing details

2. Rakes: All fixed rake details for the roof shall be secured and sealed with roof system flashing fabric and compound. If fixed rake metal is fastened to the top of roof panel ribs and extends back onto the roof, trim off any excess metal and follow horizontal seam flashing procedures. All voids and open areas shall be filled with polyurethane foam prior to application of the roof coating system flashing compound and fabric.

3. Parapet Walls: All parapet wall details within the roof system shall be secured and sealed with roof coating system flashing compound and fabric. If parapet wall flashing metal is fastened to the top of roof panel ribs and extends back onto the roof, trim off any excess metal and follow horizontal seam flashing procedures. All voids and open areas shall be filled with polyurethane foam prior to application of flashing fabric and compound.

4. Curb Flashings: All curb flashings, including cricket details, shall be flashed with roof coating system flashing fabric and compound. Encapsulate all fasteners, do not bridge fasteners. Flashing fabric shall be cut around all fasteners so the fabric lies flat.

5. Penetrations: Roof coating system flashing compound shall be applied around the base of all penetrations, extending at least 6 inches (152 mm) onto the vertical and 6 inches (152 mm) onto the base. Embed a minimum 12 inches (305 mm) width of flashing fabric using additional compound. Cut fabric to accommodate the shape of the penetration. Both the top and bottom of neoprene pipe boots shall be flashed using flashing compound as described above.

6. Skylights: Curb skylights shall be treated in the same fashion as Curb Flashings.

A. FIELD OF ROOF APPLICATION AND RATES

1. Resurfacing Metal Substrate 20 Year System:

a. Tighten and/or replace existing fasteners.

b. Power wash (or other approved cleaning method) roof to ensure it is free of dirt, debris, oil, and other contaminants that could negatively affect adhesion. Allow the roof to completely dry.

c. Before applying the roof coating system, an adhesion test is required to ensure an adhesion minimum of 2.0 PLI (0.36 kg/cm). Test patches to be applied with the rates listed below.

d. Prime rusty areas with the approved roof coating system primer at the specified rate.

e. Treat seams:

1)Loose seams: to be treated as recommended by the manufacturer and approved by the Government.

2)Vertical and Horizontal seams: to be treated as recommended by the manufacturer and approved by the Government.

f. Encapsulate exposed fasteners with the roof coating system manufacturer’s flashing system.

g. Apply first coat of the roof coating system at the rate of 1.0 gallon per 100 ft2 (4.07 L/m2) or as specified by the manufacturer in order to achieve the warranty. Allow at least 24 hours drying time, and then inspect for defects, flaws or areas of insufficient coverage. Correct any unsatisfactory conditions.

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h. Apply second coat of the roof coating system at the rate of 1.5 gallons per 100 ft2 (6.11 L/m2) or as specified by the manufacturer in order to achieve the warranty.

Allow at least 24 hours drying time, and then inspect for defects, flaws or areas of insufficient coverage. Correct any unsatisfactory conditions.

i. Apply third coat of the roof coating system at the rate of 1.0 gallon per 100 ft2 (4.07 L/m2) or as specified by the manufacturer in order to achieve the warranty. Allow at least 24 hours drying time, and then inspect for defects, flaws or areas of insufficient coverage. Correct any unsatisfactory conditions.

j. After a minimum of 24 hours has elapsed, inspect the final roof surface for flaws, areas of insufficient coverage, insufficient thickness, etc. The manufacturer’s recommended and Government-approved dry coating thickness is 29 mils in the field of the roof. All unsatisfactory areas must be repaired.

3.3 INSPECTION INFORMATION

A. Inspect Preliminary Work / Flashing Details for problem areas (e.g., gaps, cracks, fishmouths, air pockets, etc.) to ensure that work is complete and satisfactory.

B. Inform Government and manufacturer when all preliminary work and flashing details will be complete and the Installer is ready to proceed with application of the roof coating.

If necessary, allow a minimum of two (2) weeks for the interim inspection to be made by the manufacturer.

C. Any final roofing installation prior to this interim inspection is subject to rejection by the manufacturer.

3.4 OTHER ITEMS

A. Installer shall take photographs of representative roof areas, including detail work, before work commences, after the surface has been properly prepared, after all flashing and detail work has been performed, and after the spray application of the coating has been completed.

B. Special care shall be taken to avoid shading when spraying dark colors. When applying a dark color, Installer shall always spray wet material onto wet material to ensure that spray lines do not appear. Installer should also use the roof ribs or standing seams to terminate each spray pass.

C. Installer shall take special care when moving spray hoses and other equipment on the roof so that flashing work and encapsulated fastener heads are not damaged. Also, all spray equipment shall remain on the ground for the duration of the job.

D. It is strongly recommended that walkways designed for metal roofing systems be installed in all high traffic areas.

3.5 REPAIRS

A. In the event that the coating is damaged, punctured, or re-work is required, repairs are to be performed using the roof coating system flashing system (where necessary) in accordance with the manufacturer’s recommendations and generally as follows:

1. Damaged areas are to be cut, cleaned and dried.

2. Apply flashing compoung and feather out onto the existing coating system.

3. If a new penetration area has been cut, embed flashing fabric into the flashing compound according to the manufacturer’s specifications.

4. Once the flashing compound has cured, roof coating may be applied for aesthetic uniformity.

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END OF SECTION