Colorado State University. Durrell Center Roof Repair

Transcription

1 Colorado State University Durrell Center Roof Repair SPECIFICATION: POLYURETHANE FOAM ROOFING l.0 GENERAL REQUIREMENTS The successful application of a polyurethane foam roofing system is dependent upon the experience, technology and common sense of the designer and contractor. This guide specification is intended as a starting point for development of more complete specifications of roofing assemblies. The successful application of a polyurethane foam roofing system hinges on the experience, integrity and ability of the applicator/contractor. 1.1 Terms and Conditions The roofing contractor is the prime contractor. All subcontractors shall be identified and approved at the time the proposal is submitted Bidders shall be prequalified as follows: a. All bidders shall be contractors specifically engaged in the application of these systems for not less than 10 years. Each bidder shall have performed at least 5 applications of similar size and type. b. Bidders shall submit a copy of the proposed 10 year standard coating labor and material warranty from the manufacturer along with his proposal. c. The contractor shall carry a minimum of $1,000,000 in general liability insurance on a continuing basis. Verification of insurance shall be submitted at the time of the bid Qualifications of Manufacturer: The coating shall have a minimum of 1,000,000 square feet of successful roofing installed over polyurethane foam. 1.2 Submittals Manufacturer's Literature: Submit two copies of the manufacturer's data sheets regarding specifications, application information and safety information and safety instructions on each product proposed for use Samples: Submit two samples of the proposed coating system applied to urethane foam. Samples shall be two inches by four inches in size.

2 1.2.3 Certification of the Manufacturer: Submit on corporate letterhead, a letter from the manufacturer of the foam and a letter from the manufacturer of the coating stating that the applicator of these products is qualified under the manufacturer's warranty program Similar jobs: The applicator shall submit a list of five similar projects which the contractor has completed over the past five years Submit a copy of the manufacturer's 10 year labor and material warranty Submit a copy of the current UL approval for the system over non-combustible decks Materials other than those specified shall be submitted and approved in writing by the owner seven days prior to the opening of the bid. 2.0 MATERIALS AND EQUIPMENT 2.1 Primer: Primer shall be a single component primer specifically designed to improve adhesion of foam to rolled roofing The primer shall be Bayblock 004 or prior approved equal. 2.2 Polyurethane Foam: Shall be a two component polyurethane foam system formulated for use through airless equipment. The product shall be Bayseal 27 as manufactured by Bay Systems NA, Spring Texas, Premiseal 280 as manufactured by Premium Spray Products, Marietta Georgia, or prior approved equal. The product shall exhibit the following typical physical properties: Density (sprayed-in-place): 2.7 pcf min. Compressive Strength: 42 psi min. Tensile Strength: 80 psi min. Shear Strength: 45 psi min. Closed Cell Content: 90% min. K Factor initial: Flame Spread (ASTM E-84): 75 max.* Roof deck Classification: UL 790 (ASTM E-108 Noncombustible deck Class A *This numerical flame spread rating is not intended to reflect hazards presented by this or any other material under actual fire conditions. 2.3 Fluid Applied Elastomeric Coating Acrylic rubber roof coating: The elastomeric coating shall be an acrylic

3 elastomer coating based on the Rohm and Haas EC resins. The product shall be Bayblock HT as manufactured by Bay Systems NA, Spring Texas, Premicote 1500 as manufactured by Premium Spray Products, Marietta Georgia Diathon HT as manufactured by United Coatings, Charleston, SC or prior approved equal with the following physical properties: Solids Content 55% min. Elongation 912% min. Tensile Strength 430 psi min. Ultra Violet Exposure No cracking, checking 8000 hours in Atlas weatherometer or significant discoloration Roof Deck Classification UL 790 (ASTM E-108) Noncombustible deck Class A Combustible deck Class B Lower tensile strength acrylic coatings shall not be allowed. The minimum dry mil thickness of the acrylic coating shall be 44 dry mils. Materials such as silicone, single component urethanes and catalyzed Urethanes, plasticized acrylics, vinyls, asphaltics, reground rubber, EVAs and PVA coatings shall not be considered. 2.4 Equipment Equipment for spraying foam shall be manufactured specifically for the application of polyurethane foam. The equipment shall be airless, capable of maintaining a 1:1 volume ratio and have primary and hose heaters. Coating equipment shall be an airless type as recommended by the coating manufacturer. 3.0 SURFACE PREPARATION 3.1 Surface condition: The surface shall be free from solvent, grease, dust, sediment, and dirt and sticky mastic. All extraneous equipment and equipment supports shall be removed from the deck. 3.2 Around each drain, remove all roofing materials to the deck 12 feet in each direction from the drain. Remove all roofing materials from the sides of each penetration. 3.3 Prime all surfaces with 0.5 gal per square Premicoat primer or prior approved equal.

4 3.4 Install aluminum vents every 200 square feet. Slit the cap sheet under the vent. 3.5 All surfaces not to receive foam such as walls, air conditioners and other roof mounted equipment are to be carefully masked with tape and paper to avoid over spraying of these surfaces with foam or coating. All coating is to be terminated in clean straight lines. 4.0 APPLICATION OF URETHANE FOAM 4.1 Environmental Conditions Wind velocity shall not exceed 12 miles per hour Application of spray foam shall not proceed if ambient temperature is less than 40 degrees F or if the substrate temperature is less than 50 degrees F Spray foam is not to be applied over moist substrates or where rain or inclement weather is eminent. 4.2 Spray Application The polyurethane foam shall be applied in minimum one half inch passes. The foam shall applied at a thickness of 1.5 inch and tapered uniformly to one inch at the drains. Encapsulate flashing on the parapet walls with foam Only as much area as can be brought to final thickness should be attempted in a day. Phasing of the foam is strictly forbidden. (Phasing is foam application on one day and coming back the next day or hereafter and a applying another layer of foam over the old foam. This procedure often leads to the development of blisters down the road.) If additional foam must be added after the 24 hour period, the existing foam must be primed with Futura 502 or equal and a minimum of one half inch of foam applied in a single pass The foam shall be free from bumps, pinholes and ridges. The surface shall exhibit a smooth or orange peel texture. Popcorn or tree bark surfaces shall be deemed unacceptable The foam thickness shall be checked every 500 square feet prior to coating application.

5 5.0 APPLICATION OF FLUID APPLIED PROTECTIVE COATING 5.1 General Sprayed polyurethane foam must be protected from ultraviolet light in order to avoid degradation of the polymer. Coating also protects the foam from liquid water and adverse weather conditions. Coatings must be specifically formulated for use over urethane foams. 5.2 Spray application Coating and Granules The coating is to be applied to the surface of the urethane foam in three uniform passes. The base coat, intermediate and top coat shall be of contrasting colors to assure uniformity of coverage. A total of 44 dry mils shall be applied to the foam as determined by an optical comparator. The coating shall be applied in the following sequence: a. Spray apply 1.5 gallons per 100 square feet of high tensile acrylic, Ivory to achieve a dry mil thickness of 12 dry mils. b. Spray apply 1.5 gallons per 100 square feet of high tensile acrylic white to achieve a dry mil thickness of 12 dry mils. While the top coat is still wet, broadcast white sand granules into the wet top coat at a rate of 25 lbs per square. c. After the intermediate coat has cured, spray apply 2.5 gallons per 100 square feet of high tensile acrylic white to achieve a dry mil thickness of 20 dry mils. While the coating is still wet, broadcast white sand granules into the wet top coat at a rate of 45 lbs per square. d. The total dry film thickness of the coating shall be 44 dry mils. Exception: The parapet walls shall receive 26 mils of Bayblock HT and shall not be granulated. The granule coverage shall be uniform and voids and bald spots (shiners) shall not be allowed. 6.0 WARRANTY AND CERTIFICATION The coating manufacturer shall issue a 10 year non depreciating manufacturer' warranty covering leakage. The coating manufacturer is to supply coating and labor for all repairs covered under the warranty. 7.0 INSPECTION

6 A representative from the coating manufacturer shall inspect the roof after completion to assure that the detail work at the protrusions, drains, parapets and edges have been completed in conformance with good practice. The inspector shall also check the thickness of the coating with an optical comparator. End