Spec Disk 1998 Spring 4.0

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SECTION 07570 COATED FOAMED ROOFING NOTE ** Foam Enterprises coated polyurethane foam systems for new and remedial roofing. NOTE ** NOTE ** This section is based on the products of Foam Enterprises, Inc., which is located at: NOTE ** 13630 Water Tower Circle NOTE ** Minneapolis, MN 55441 NOTE ** Tel: (800) 888-3342 NOTE ** Fax: (612) 559-0945 NOTE ** NOTE ** There are three different but similar systems described in this specification: NOTE ** 1. Coated foam roofing over conventional substrates and over existing built-up roofing. NOTE ** 2. Aggregate-covered foam roofing over conventional substrates and over existing built-up roofing. NOTE ** 3. Repair and re-coating of existing coated foam roofing. NOTE ** NOTE ** SECTION 07570 - COATED FOAMED ROOFING, Copyright 1997, The Architect's Catalog, Inc. NOTE ** This specification is based on three guide specifications prepared by the Technical Committee of the Spray Polyurethane Foam Division of the Society of the Plastics Industry, Inc. (800) 541- 0736: NOTE ** NOTE ** Spray Polyurethane Foam Systems for New and Remedial Roofing, copyright 1994, SPI, Inc. NOTE ** Spray Polyurethane Foam Aggregate Systems for New and Remedial Roofing, copyright 1990, SPI, Inc. NOTE ** The Renewal of Spray Polyurethane Foam and Coating Roof Systems, copyright 1994, SPI, Inc. NOTE ** NOTE ** SPI publishes many other guides for the use of spray polyurethane foam that may be of assistance in selecting products and preparing a specification. PART 1 GENERAL 1.1 SECTION INCLUDES NOTE ** Edit items below as required for project. A. New sprayed polyurethane foam roofing with elastomeric coating. B. New sprayed polyurethane foam roofing with aggregate cover. C. Repair and re-coating of existing coated polyurethane foam roofing. 1.2 RELATED SECTIONS NOTE ** Delete any sections below not relevant to this project; add others as required. A. Section 03300 - Cast-ln-Place Concrete: Requirements for finishing and curing concrete roof deck. B. Section 05300 - Metal Deck: Requirements for deck materials, support, deflection, and slope. C. Section 06100 - Rough Carpentry: Requirements for wood deck materials, support, deflection, and slope. D. Section 07600 - Flashing and Sheet Metal: Metal trim and flashings associated with roofing. E. Section 07700 - Roof Specialties and Accessories: Roof expansion joints, vents, prefabricated copings and trim. F. Section 08620 - Unit Skylights. G. Section 13100 - Lightning Protection. H. Division 15 - Mechanical: Plumbing and HVAC components penetrating roof. I. Division 16 - Electrical: Electrical components penetrating roof. 1.3 REFERENCES NOTE ** Add any references to the list below that are included in text you have added to the section. A. ASTM C 177 - Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus. B. ASTM C 518 - Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus. C. ASTM D 412 - Standard Test Methods for Vulcanized Rubber and Thermoplastic Rubbers and Thermoplastic Elastomers-- Tension. D. ASTM D 822 - Standard Practice for Conducting Tests on Paint and Related Coatings and Materials using Filtered Open-Flame Carbon-Arc Light and Water Exposure Apparatus. E. ASTM D 1621 - Standard Test Method for Compressive Properties of Rigid Cellular Plastics. F. ASTM D 1622 - Standard Test Method for Apparent Density of Rigid Cellular Plastics. G. ASTM D 1863 - Standard Specification for Mineral Aggregate Used on Built-Up Roofs. H. ASTM D 2856 - Standard Test Method for Open-Cell Content of Rigid Cellular Plastics by the Air Pycnometer. I. ASTM E 84 - Standard Test Method for Surface Burning Characteristics of Building Materials. J. ASTM E 96 - Standard Test Methods for Water Vapor Transmission of Materials. K. ASTM E 108 - Standard Test Methods for Fire Tests of Roof Coverings. L. SPI Bulletin AX-119 - MDI-Based Polyurethane Foam Systems: Guidelines for Safe Handling and Disposal; Society of the Plastics Industry, Inc., Spray Polyurethane Foam Division. M. SPI SFPD - Sprayed Polyurethane Foam Surface Visual Guide; Society of the Plastics Industry, Inc., Spray Polyurethane Foam Division. N. SSPC-SP 6 - Commercial Blast Cleaning (Part of Painting Manual, Volume 2); Steel Structures Painting Council. 1.4 SUBMITTALS NOTE ** Delete types of submittals not required. Coordinate submittal statements with other provisions in the section. A. Submit under provisions of Section 01300. B. Product Data: Manufacturer's data on products to be installed. 1. Application or installation instructions. 2. Listing, classification, and approval certifications. 3. Safety and handling instructions for storage, handling and use of the materials. NOTE ** Delete the following paragraph if a warranty is not required. 4. Warranty: A specimen copy of the applicable warranty. C. Product Certification: SPI/SPDF accreditation test for materials. D. Certifications: If manufacturer's published data sheets do not indicate compliance with all specification requirements, provide letter of certification that all products comply with the specification requirements; include primers (if required), foam and coatings. E. Shop Drawings: Show materials and details of fabrication of sheet metal, accessories, or other fabricated items. F. Qualification Statements: 1. Manufacturer qualifications. 2. Installer qualifications. 3. Independent inspector qualifications. G. Applicator's Field Quality Control Procedures: Written description of procedures to be utilized to insure proper preparation and installation of sprayed foam and coatings, detail work and follow-up inspection. H. Executed warranty, at completion of work. I. Maintenance Data: Manufacturers' recommended protection, cleaning, and repair procedures, including recommended frequency of inspection. NOTE ** It is strongly recommended that a maintenance program, including annual inspections, be established with the installer for the roofing system to achieve its full value. 1. Include proposal for annual inspection program. 1.5 QUALITY ASSURANCE A. Foam Surface Finishes: As defined in SPI Spray Polyurethane Foam Division sprayed polyurethane foam surface visual guide. Provide two copies; maintain one copy on site at all times. NOTE ** Delete the following qualifications statements if manufacturers have been pre-qualified or approved before issuance of bidding documents. In addition, these provisions may not be necessary if a single- source warranty is specified below. Delete if not required, as these provisions add cost to the project. B. Foam and Coating Manufacturer Qualifications: Firms which can show evidence of ability to manufacture the products specified and sufficient financial resources and manufacturing facilities to furnish materials on this project; evidence required includes references, past project descriptions, specimen warranty, product data, test data, and code approvals. C. Installer Qualifications: A firm with experience installing roofing systems of the type specified. NOTE ** Delete the following paragraph if not required. NOTE ** NOTE ** The Society of the Plastics Industry Spray Polyurethane Foam Division conducts an Accreditation Program for improvement of quality in the application of spray polyurethane foams and coatings. NOTE ** NOTE ** The list of accredited individuals and firms is available from SPI/SPFD. 1. Show contractor/supplier level accreditation by SPI SPFD Accreditation Program. NOTE ** Delete the following paragraph if the roofing system manufacturer does not have an approved installer program. 2. Approved or certified by the roofing system manufacturer as qualified to install the specified system. 3. Provide information concerning projects similar in nature to the one proposed including location and person to be contacted. D. Manufacturer Field Representation: Provide qualified representatives of the foam and coating manufacturers to monitor and inspect the installation of their products. NOTE ** Independent inspection is highly recommended, especially if single source responsibility is not specified or no warranty is specified. E. Independent Inspection: Provide inspection of the installation by a qualified SPI SPFD inspector member. 1.6 DELIVERY, STORAGE, AND HANDLING A. Provide materials packaged in the manufacturer's original, tightly sealed containers or unopened packages, clearly labelled with the manufacturer's name, product identification, safety information, and batch or lot numbers where appropriate. Where materials are covered by a referenced specification, the labels shall bear the specification number, type and class, as applicable. B. Store materials out of the weather and out of direct sunlight in locations where the temperatures are within the limits specified by the manufacturer. C. Deck Sheathing: Take special care to prevent these materials from getting wet in storage. 1.7 PROJECT CONDITIONS A. During installation, keep the roof free of personnel other than the roofing installers. NOTE ** Normally safety procedures are the responsibility of the contractor. For more information about polyurethane foam see SPI Bulletin AX-119, "MDI-Based Polyurethane Foam Systems: Guidelines for Safe Handling and Disposal." B. Comply with the manufacturer's instructions and recommendations as to handling and safety procedures. 1.8 WARRANTY NOTE ** Warranty agreements vary in duration and content. If a warranty is desired, determine which entity will provide it and what the terms will be before entering into a contract. The following paragraphs are only examples -- be sure someone will actually provide a warranty with the terms you specify. NOTE ** NOTE ** The following paragraph allows the contractor to choose who will provide the warranty -- edit if a specific entity is required. A. Provide a roofing system warranted by a single entity, either the entire roofing system manufacturer, the foam or coating manufacturer, or the installer. 1. Warranty Term: _____ years from Date of Substantial Completion. 2. Conditions: Warrant roofing system against delamination, blistering, cracking, and failure of coating to keep foam dry. PART 2 PRODUCTS 2.1 MANUFACTURERS A. Provide coated foam roofing system manufactured by Foam Enterprises, Inc., 13630 Water Tower Circle, Minneapolis, MN 55441. ASD. Tel: (800) 888-3342. Fax: (612) 559-0945. NOTE ** Delete following paragraph if substitutions are allowed. B. Substitutions are not acceptable. NOTE ** Delete following paragraph if no substitutions are allowed. Edit Section Number as required for project. C. Submit requests for substitutions in accordance with provisions of Section 01600. 2.2 COATED FOAM ROOFING SYSTEM NOTE ** When spray applied polyurethane foam is applied outdoors, as part of the roofing system, it must be protected from ultraviolet light and weather. Both aggregate (gravel) and elastomeric coatings are used for this purpose. Aggregate covering has an upper slope limit of 1/2 inch per foot. If steeper slopes are also present, both the aggregate and coating systems may be required on the same project. NOTE ** NOTE ** Delete all but one of the following four paragraphs. The first three are coated systems and the fourth is an aggregate covered system. NOTE ** NOTE ** It is the responsibility of the specifier to evaluate the loadbearing capacity of the roof deck to insure safe weight limits are not exceeded. A. Coated Foam Roofing System: Foam Enterprises, Inc., FE303-2.7 with FE Acrylic Coating. B. Coated Foam Roofing System: Foam Enterprises, Inc., FE303-2.7 with FE Silicone Coating. C. Coated Foam Roofing System: Foam Enterprises, Inc., FE303-2.7 with FE Urethane Coating. D. Foam Roofing System: Foam Enterprises, Inc., RockFoam Roofing System. E. Performance Characteristics: NOTE ** The following properties are examples only. Obtain information from the manufacturer as to what characteristics are available. 1. Underwriters Laboratories listed and classified. 2. Factory Mutual approved. 3. Tested as a component of a fire-resistive roof- ceiling assembly, with hourly rating of ______. 4. Fire Classification in accordance with ASTM E 108: Class A. 5. Fire Classification in accordance with ASTM E 108: Class B. 6. Wind Uplift Classification: _______. NOTE ** Specify the foam thickness below. The minimum thickness recommended is one inch. F. Foam Thickness: _____ inch(es) (_____ mm). 2.3 MATERIALS NOTE ** Most published data is run on laboratory produced samples, not in-place material. The thickness of polyurethane foam sprayed, number of passes, temperature of substrate, ambient temperatures, etc., all affect properties. The following values are for Foam Enterprises' product in-place. A. Foam: Sprayed-in-place two-component closed-cell polyurethane made by combining an isocyanate (A) component with a polyol (B) component, with the following physical characteristics: 1. Density in place, when tested in accordance with ASTM D 1622: 2.7 lb/cu ft (43 kg/cu m). 2. Compressive Strength, when tested in accordance with ASTM D 1621: 35 to 60 psi (2.4 to 4.1 Pa). 3. Closed Cell Content, when tested in accordance with ASTM D 2856: 85 percent, minimum. 4. Thermal Conductivity ("K"), when measured in accordance with ASTM C 177 or C 518: 0.15. 5. R-Value, aged: 6.67. NOTE ** From a fire safety standpoint, polyurethane foams can be used safely. It is important, however, that all persons associated with the design, fabrication, storage and installation understand the materials and environments involved. NOTE ** NOTE ** Polyurethane foam insulation is combustible and should be treated as such. Flame spread ratings provided for polyurethane products using small scale tests are not intended to reflect the hazards presented by this or any other materials under actual fire conditions. Care must be taken to ensure that the foam is not exposed to heat or flame. 6. Flame Spread Index, when tested in accordance with ASTM E 84: Less than 75. 7. Smoke Developed Index, when tested in accordance with ASTM E 84: Less than 450. B. Foam for Repair of Existing Foam Roofing: Same type as existing, or compatible type, with same density and compressive strength as original foam as-installed. (Many commercial "froth packs" and pour foams will not give satisfactory results.) C. Primers: As recommended by the manufacturer of the spray foam materials specified. NOTE ** The following granules are optional for coated systems. D. Granules: Size and type as recommended by the coating manufacturer, for application in the top coat. NOTE ** The following materials are for the aggregate covered system only. NOTE ** NOTE ** A secondary UV barrier coating may be applied prior to aggregate application. E. Secondary UV Barrier Coating: Permeability as applied not less than 5.0 perm inch (7.25 ng/Pa s m) when tested in accordance with ASTM E 96, Perm Inch Method, and as recommended by the foam manufacturer. NOTE ** The selection of gravel or slag is usually determined by local availability; the size of the gravel/slag is more important than the type. A mixture of gravel/slag sizes should be used, with the larger pieces approaching 3/4 inch. Flat surfaced gravel/slag is preferable to round. F. Aggregate: Gravel or slag complying with ASTM D 1863 Size No.7 (1/2 inch to sieve size 4) or Size No.67 (3/4 inch to sieve size 4). 2.4 ACCESSORY MATERIALS A. Flashings and Waterproof Coverings for Expansion Joints: Compatible with the foam and coating system and as recommended by roofing system manufacturer. B. Other Materials Used in Roofing System: Selected for compatibility with roofing system materials and as recommended by the roofing system manufacturer; including, but not limited to, adhesives, sealing and caulking compounds, metal flashings, vents and drains. NOTE ** The following deck sheathing is normally not needed except over metal decks. Verify for project. Select type required. C. Deck Sheathing: Insulation boardstock. D. Deck Sheathing: 5/8 inch (16 mm) thick gypsum sheathing. NOTE ** The following mesh fabric is for use over fluted metal deck. Verify with roofing system manufacturer that it is appropriate for use with that system. E. Mesh Fabric: Open weave mesh as recommended by roofing system manufacturer. NOTE ** Protection from damage due to roof traffic is recommended, especially at heavy traffic areas and around frequently serviced roof top units. F. Walkway Pads: Breathable type as recommended by the coating manufacturer. PART 3 EXECUTION NOTE ** Spray polyurethane foam can be successfully applied to most surfaces. However, the following general practices must be observed on all decks which are to receive spray applied polyurethane foam. Be sure that these requirements are adequately covered in other specification sections or on the drawings. NOTE ** NOTE ** The roof deck should be securely fastened to the building structure and conform to proper load limits of good engineering practices. Special attention should be focused on the deflection rate under all types of roof conditions, including but not limited to, foot traffic, mechanical equipment utilization, as well as live and dead loads. NOTE ** NOTE ** When a primer and/or a vapor retarder is specified, there must be adequate adhesion between all components of the system to secure the entire system against wind uplift and movement. 3.1 GENERAL A. Comply with the instructions and recommendations of the roofing system manufacturer. B. Familiarize all installers with correct and safe application and handling procedures: 1. See SPI Bulletin AX- 119, "MDI-Based Polyurethane Foam Systems: Guidelines for Safe Handling and Disposal." 2. Refer to appropriate Materials Safety Data Sheets (MSDS) for additional safety information. C. Before starting to apply foam or coating, shut off all HVAC equipment on the roof and seal air intakes and exhausts. Seal other potential sources of air entry into the building. 3.2 PREPARATION OF EXISTING BUILT-UP ROOFING (RETROFIT) NOTE ** Polyurethane foam may be installed over existing built-up roofing, with the following cautions: NOTE ** NOTE ** Aggregate covered systems are heavier than elastomeric coated systems and it may be necessary to have a structural design analysis conducted by a licensed engineer to determine if the roof structure is capable of supporting it. NOTE ** NOTE ** Under no circumstances should this system be installed over a roof structure containing two or more overlaid existing built-up roofs. Removal of the existing roofing is in these cases required. A. Remove all loose gravel, dust and residue using power vacuum equipment, power sweeper, air blowing, or other suitable means. B. Thoroughly inspect or test the roofing to determine if moisture is present within the roof assembly. Remove moisture-saturated insulation and replace with compatible materials. C. Thoroughly inspect the roofing for adhesion between felts, insulation, and deck. Fasten down areas of poor adhesion. Cut out or fasten down blisters, buckles, wrinkles and fishmouths. D. Remove all soft mastic or other materials that might interfere with foam adhesion. E. Remove or refasten all loose base flashing, counterflashing and gravel stops as required. F. Inspect existing expansion joints and repair if necessary. NOTE ** Delete the following paragraph if not required. Lightning rod cables must not be embedded in the foam. G. Mask lightning rods and remove lightning rod cables prior to foaming. H. Relocate electrical and mechanical conduits or temporarily raise them above the finished roof surface. 3.3 PREPARATION OF EXISTING SPRAY POLYURETHANE ROOFING FOR RECOATING NOTE ** Sprayed-in-place coated polyurethane foam roof systems that have been applied and maintained according to industry standards can be re-coated (renewed). The performance of a sprayed in place polyurethane foam roof system renewal can be affected by all the component parts of the roof structure, as well as the atmospheric conditions inside and outside the structure. NOTE ** NOTE ** Structural design, code compliance, specification review, contractor and material selection, should be considered in the renewal of a polyurethane foam roofing system. Consult with the material suppliers and the installer to receive written confirmation of their agreement to all facets of the system to be used. This should include, but not be limited to, material selection, expansion joints and flashing details. NOTE ** The preparation for renewal will vary according to the condition of the roof and its component parts and the type of protective coating used over the polyurethane foam. NOTE ** NOTE ** This specification assumes that the determination of how much preparation work is required will be done under the actual re-coating contract. This may not result in a good fixed price for the work. It may be necessary to have the roof inspection and analysis conducted under another contract and add a description of the exact work to be done to this specification. A. Conduct a complete roof inspection to determine the repairs to be performed and the type of materials to be used. 1. Perform a visual inspection to identify: a. Blisters and delaminated areas in the original roof. b. The condition of the roofing system at all flashing and termination points. c. Splits and cracks in the foam. d. Damage from impact such as foot traffic, hail, dropped tools, etc. e. Pinholes in the foam and/or coating. f. Exposed areas of foam and areas of eroded (thin) coating. g. Areas of ponding water. 2. Perform a non-destructive moisture survey. Further inspect suspected moisture laden areas with a moisture probe or core samples. 3. Probe to determine foam thickness. 4. Take samples of the existing system as required by the manufacturer of the re-coat system to be applied. B. Submit a report of the inspections and results of analysis: 1. Analyze samples for: a. Adhesion of existing foam to the substrate. b. Interlaminar adhesion of foam. c. Presence of moisture. d. Adhesion of base coat to foam. e. Adhesion of top coat to base coat. f. Type and condition of protective coating. g. Thickness of protective coating. 2. On a roof sketch indicate the following items and deficiencies: a. Location of core and slit samples. b. Areas of pinholes. c. Uncured coating. d. Blisters in foam or coating. e. Mechanical damage. f. Poor drainage. g. Repairs required for foam stops, parapet walls, gutters, scuppers, edge terminations, expansion joints, counterflashing, and other perimeter items. h. Repairs required to soil and vent pipes, drains, roof hatches, equipment curbs or supports, guy wires, hot stacks, skylights, mechanical units, walkways, sleepers, pitch-pans and other penetration items. i. Water saturated sub-roofs, insulation, or foam. j. Sub-roof damage or deterioration. k. Areas of special consideration. C. From the inspection, determine items that need to be corrected. D. Replace or repair substrate that is unacceptable. E. Remove and replace blistered foam, using the following guidelines: 1. Take test cuts (core or slit samples) in areas of blistered foam to determine the cause and extent of the problem. It may be necessary to remove foam beyond the actual area of an individual blister in order to prevent reoccurrence. The surface area adjacent to the cut should be prepared and cleaned. 2. If a number of blisters are found clustered in one area, remove the top pass or top two passes in the area rather than attempting to repair individual blisters. 3. Do not cut out a blister and fill with coating. Such a procedure will result in either a depression in the surface which will hold water or an unacceptable thickness of coating which may itself blister or crack. 4. After opening a blister or removing a foam layer, inspect the lower layer for degradation or moisture. No repair procedure should be attempted to a degraded or moist surface. Dry the surface and remove degraded area before proceeding to repair. F. Remove unacceptable coating. Consult coating manufacturer for definition of unacceptable coating and methods of removal. 1. Apply new coating to proper thickness to repaired areas. 2. Two or more coats should be used. Final dry mil thickness of repaired areas should be as specified. G. Small blisters, small cracks, breaks in the foam or coating, bird pecks, or hail damage may be repaired with a compatible sealant. 1. Do not install sealant in a greater area or thickness than is recommended by the manufacturer for proper cure. 2. Install sealant so as to insure the final surface is higher than the surrounding area so that water will not remain on the repair area. 3. Use the type of sealant recommended by the coating manufacturer. 4. Make the area to be repaired clean, dry, and bevel the edges to assure proper adhesion. 5. In some cases, foam core plugs can be used with sealant to make small repairs. H. If weathering has caused the surface of the coating and the foam to degrade (pitting), grind off or scarf the surface to expose clean, dry foam. NOTE ** Addition of roof drains or scuppers is another option to eliminate ponding. That would not be part of the roofing installers work unless so indicated. I. Build up low areas to eliminate ponding by applying foam. Follow manufacturer's recommendation for surface preparation. J. Repair or replace deteriorated flashings, roof jacks, metal work, curbs, supports, penetrations, drains, etc. K. Thoroughly clean the existing coated roof surface of dust, dirt, oils, and other contaminants by power washing, brooming, and/or blowing as recommended by the coating manufacturer. 3.4 PREPARATION OF METAL DECK NOTE ** The following considerations apply to metal roof deck and panels used as substrate for coated foam roofing. Be sure that other sections of the specification, or the drawings, cover these requirements. NOTE ** NOTE ** The metal roof deck should be constructed of minimum 22 gauge steel and construction should conform to local building codes. A pitch of 1/4 inch in 12 inch or more is recommended, to avoid potential ponding due to deflection of the deck. For aggregate covered applications, the pitch should not exceed 1/2 inch in 12 inches. NOTE ** NOTE ** Sloped metal roof panels (with supplementary support) should not be lighter than 29 gauge. NOTE ** NOTE ** All joints should be correctly lapped, sealed and fastened. NOTE ** NOTE ** Underlayment, if specified for smoother application of polyurethane foam should be of sufficient width and thickness to span or fill flutes. Fastening should be in accordance with applicable code requirements. A. Ferrous Metal: Sandblast iron and steel surfaces which are not primed, shop painted, or otherwise protected in accordance with SSPC SP-6. Remove loose rust and unsound primer from shop primed iron and steel surfaces by scraping or wire brushing. B. Non-Ferrous Metal: Clean galvanized metal, aluminum, and stainless steel surfaces as recommended by the roofing system manufacturer. C. If metal surface is free of loose scale, rust, weathered or chalking paint, clean using compressed air jet, vacuum equipment, and hand or power broom to remove loose dirt. Remove grease, oil and other contaminants using proper cleaning solutions. NOTE ** Fluted metal decks require a suitable method of covering or filling the flutes prior to polyurethane foam application. Flutes may be covered with mechanically fastened board stock, open weave mesh fabric, or filled with precut board stock or spray applied polyurethane foam. NOTE ** NOTE ** Delete one of the following 2 paragraphs. D. Fluted Metal Deck: Cover or fill flutes by method recommended by roofing manufacturer. E. Fluted Metal Deck: Cover with deck sheathing, fastened to achieve wind uplift requirements specified for roofing system. 1. Butt boards firmly butted together along all edges without gaps or openings. Calk joints more than 1/4 inch (6 mm) wide with a suitable sealant material. 2. Special care must be taken to prevent these materials from getting wet in storage on the job site and after installation prior to being protected by foam. Moisture exposure will damage these materials and may be a cause for replacement. 3. Remove loose dirt and debris by using compressed air, vacuum or light brooming. Do not power broom sheathing due to possibility of damage. 4. Protect installed sheathing from spills of contaminants such as oil, grease, solvents, etc., as these materials cause soiling that cannot be readily removed from the board surfaces. 3.5 PREPARATION OF CONCRETE DECK NOTE ** Lightweight or insulating concrete decks are not recommended as substrates for sprayed polyurethane foam unless tests are made to determine that adequate adhesion can be obtained or unless an overlay of other suitable material is installed. A. New Concrete: Allow to cure for twenty-eight (28) days prior to the application of primer or foam. B. Remove loose dirt, dust and debris by using compressed air, vacuum equipment or brooming. Remove oil, grease, form release agents, laitance, and other contaminants using proper cleaning solutions. C. Grout or calk all joint openings in concrete decks that exceed 1/4 inch (6 mm) in width prior to application of foam. D. Prime all concrete surfaces. 3.6 PREPARATION OF WOOD DECK NOTE ** Plywood should be exterior grade not less than 1/2 inch thick, nailed firmly in place and attachment should meet building code requirements for resistance to wind uplift. Deflection should be limited to 1/240 of the span when subjected to maximum design load (including aggregate covering, if used). NOTE ** NOTE ** Plywood should contain no more than 18 percent moisture, measured in accordance with ASTM D 4444 or ASTM D 4442. NOTE ** NOTE ** Priming is required to minimize moisture absorption and eliminate potential adhesion problems. A. Prime all untreated and unpainted surfaces with an exterior grade primer. B. Tape or fill plywood joints more than 1/4 inch (6 mm) wide with a suitable material. C. Clean deck of loose dirt, grease, oil and other contaminants prior to priming or foam application. Remove loose dirt or debris by use of compressed air, vacuum or brooming. Do not wash with water. NOTE ** Tongue and groove decks: Due to the frequency of joints, possibility of variable openings and effects of aging and shrinking, these surfaces must be overlaid with minimum 1/4 inch thick exterior grade plywood or suitable covering. D. Tongue & Groove Sheathing and Planking: Cover with deck sheathing, fastened to achieve wind uplift requirements specified for roofing system. 3.7 FOAM APPLICATION NOTE ** Delete this entire article if only re-coating an existing coated foam roof. A. Do not begin application of foam until all preparation requirements have been completed. B. Inspect substrate to determine whether sufficient slope exists to eliminate excessive ponding of water. Ponding is defined as an area of 100 square feet (9.2 sq m) or more which holds in excess of 1/2 inch (13 mm) of water as measured 24 hours after a rainfall. C. Do not apply foam during inclement weather or when the temperature or humidity is below that specified by the manufacturer for ambient air and substrate. Use wind barriers if wind conditions could affect the quality of installation. D. Apply foam in accordance with the manufacturer's specifications and instructions. NOTE ** If the substrate does not have sufficient slope, then the ponding water must be eliminated by building in slope by the application of polyurethane foam, channeling the polyurethane foam or by the proper placement of drains, or a combination thereof. If drainage channels are cut into the foam after installation at least one inch of foam thickness should remain beneath the channel. E. Build up low areas that could cause ponding by filling in with sprayed foam before the specified thickness of sprayed foam is applied to the entire roof surface. F. Apply foam with minimum pass thickness of 1/2 inch (13 mm). G. Apply foam uniformly over the entire surface with a tolerance of plus 1/4 inch per inch (6 mm per 25 mm) of thickness minus 0 inch (0 mm), except where variations are required to insure proper drainage or to complete a feathered edge. H. Complete the full thickness of foam in any area prior to the end of each day. If due to weather conditions more than 24 hours elapse between foam application and coating application, inspect the foam for UV degradation, oxidation or contamination and, if any of these conditions exist, prepare the surface in accordance with the recommendations of the roofing system manufacturer. I. Uniformly terminate foam a minimum of 4 inches (100 mm) above the roof line at all penetrations (except drains, parapet walls, or building junctions). Make foamed-in- place cants smooth and uniform to allow positive drainage. J. Skylights: Terminate foam below weep holes. Do not cover weep holes with foam or coating. K. Finish the final sprayed foam surface to "smooth," "orange peel," "coarse orange peel," or "verge of popcorn" as defined in the SPI Sprayed Foam Surface Visual Guide. Remove surfaces classified as "popcorn" and "treebark" and reapply to an acceptable surface. L. Allow the foam surface to cure sufficiently. M. Repair damage and defects to the surface prior to the protective coating application. N. Keep the foam surface free of moisture, frost, dust, debris, oils, tars, grease or other materials that could interfere with adhesion of the protective coating. 3.8 PROTECTIVE COATING APPLICATION NOTE ** Delete all but one of the following three paragraphs depending on whether the coating is to be applied over the entire existing coated foam roof, over a new foam application, or only where aggregate would not be stable (new application). A. Apply coating over entire surface of existing foam roofing. B. Apply coating over entire surface of foam. C. Apply coating over foam at sloped surfaces exceeding 1/2 inch in 12 inches (1:24), vertical surfaces and other surfaces which will not hold aggregate, including exposed roof edges. 1. Extend coating a minimum of 12 inches (300 mm) onto the flat area of the roof, from penetrations or vertical surfaces. 2. Apply coating at minimum thickness of 30 dry mils (0.08 mm) total. D. Inspect the foam surface prior to the application of the protective coating for suitability of base coat application. E. Do not apply coating during inclement weather. Do not apply when the temperature is below or the humidity is above that specified by the manufacturer for ambient air and substrate. Use wind barriers if wind conditions could affect the quality of installation. F. Base Coat: Apply the same day as the foam application when possible. 1. Wait at least two hours after application of the foam before application of the base coat. 2. If more than 24 hours elapse prior to the application of base coat, inspect the foam for UV degradation. 3. Apply the base coat at a uniform thickness with the rate of application being governed by the foam surface texture. 4. Apply coating at such a rate as to give the specified minimum dry film thickness. 5. Allow the coating to cure. 6. Inspect for pinholes, thinly coated areas, uncured areas or other defects. Repair defects prior to subsequent coats. 7. Keep the base coat free of dirt, dust, water, and other contaminants until application of the top coat. G. Top Coat and/or Subsequent Coat: 1. Apply subsequent coats in a timely manner to insure proper adhesion. 2. Apply additional material in areas of coarse foam profile. H. Inspect the cured dry film thickness of the finished coating by taking slit samples and examining under magnification. Apply additional coating to areas that are found to have less than the thickness specified. NOTE ** Granules in the top coat are optional. I. Apply granules in the top coat at the rate recommended by the coating manufacturer. 3.9 AGGREGATE APPLICATION A. Apply secondary UV barrier coating over entire uncoated area of foam, with minimum thickness to achieve required perm rating. B. Apply aggregate to achieve a minimum 3/4 inch (20 mm) thickness over all flat portions of the roof at a rate of 500 to 600 lbs per square (24 to 30 kg/sq m). 1. Store aggregate on the roof in small piles near the roof perimeter to minimize stresses to the roof deck. 2. Rake aggregate after most has been applied to insure uniform distribution. 3. Add additional gravel to areas thinner than 3/4 inch (20 mm). C. Inspect the entire flat roof surface visually to verify that the foam is completely covered with at least 3/4 inch (20 mm) of aggregate. 3.10 WALKWAYS NOTE ** Protection from damage due to roof traffic is recommended, especially at heavy traffic areas and around frequently serviced roof top units. Breathable walk pads should be as recommended by the coating manufacturer. A. Install walkway pads where indicated on drawings. END OF SECTION