Specification:Metal window restoration

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=GENERAL=

DESCRIPTION
 This specification provides guidance for the appropriate repair and restoration of metal windows. This specification has been developed for use on historic properties (defined as any district, site, buildings, structure, or object that is listed in or eligible for listing in the National Register of Historic Places) and provides an overview of accepted practices. All work described herein and related work must conform to the Secretary of the Interior’s Standards for the Treatment of Historic Properties. The Contractor shall provide all labor, materials, equipment, and operations required to complete the rehabilitation work indicated herein. All work described herein and related work must have the approval of a Cultural Resources Manager, Conservator, Historic Architect, or other professional who meets the standards outlines in the Secretary of the Interior’s Standards – Professional Qualifications Standards pursuant to 36 CFR 61. Such person is referred to in this document as the Architect. The Architect will provide site-specific specifications, when appropriate. 

SECTION INCLUDES
 Restore existing metal windows as indicated, including repair and adjustment of metal sashes and frames, reglazing, and hardware repairs and, where indicated, replacement of all or parts of individual window assemblies. Metal windows typically will be of rolled steel construction, but may include copper, aluminum, bronze, nickel, or iron, and may be of hollow-metal construction. Where metal sash are set directly to wood frames, Contractor will be responsible for making any needed repairs to wood window frames, unless otherwise specified by Architect.  Rake exterior glazing bead to remove cracked or loose putty. Assume 100% of exterior glazing putty must be removed and replaced.</li> Rake interior glazing bead to remove loose putty. Assume 100% of interior glazing putty must be removed and replaced.</li> Where leading glass currently exists, refer to Section XXXX – Specialty Glazing.</li> </ol> </li> </ol>

RELATED SECTIONS
<ol type="A"> Section 08800 – Glass and Glazing.</li> Section 09900 – Painting</li> Section 08750.01 – Window Hardware and Fittings</li> Section XXXX – Specialty Glazing</li> Section 08580.01 – Storm Windows and Screens</li> Section 08580.01 – Wood Window Restoration</li> </ol>

SUBMITTALS
<ol type="A"> Window Schedule: The Contractor shall submit a detailed schedule to the Architect for all window openings to be restored, including opening sizes as verified in field, number and sizes of lights, type of hardware, etc. Schedule shall also classify existing window hardware for each opening in accordance with the types and styles set forth in the drawings.</li> Product Literature: The Contractor shall submit manufacturer’s product literature to the Architect for all proprietary products specified for window restoration and cleaning work such as putty, epoxy fillers, caulk, cleaning agents, etc.  Product literature shall include specification data, Material Safety Data Sheets, and instructions for storage, handling, and use.</li> Samples: The Contractor shall submit to the Architect a sample of each type and style of hardware items and other window components to be used for repair and restoration of the metal windows.</li> </ol>

QUALITY ASSURANCE
<ol type="A"> The Contractor shall have a minimum of seven (7) years experience in repair and restoration of metal windows.. He/she shall have successfully completed at least three window restoration projects of similar scope within the previous five years. The contractor shall also demonstrate a working knowledge of the Secretary of the Interior’s Standards for the Treatment of Historic Properties.</li> The Contractor shall provide, in writing, a two (2) year warranty on the repair and restoration work, and copies of any manufacturer’s warranties on replacement parts.</li> </ol>

MOCK-UPS
<ol type="A"> The Contractor, at locations determined by the Architect, shall prepare mock-ups of the following work: <ol> <li>Restoration of one existing operable metal window sash, including hardware.</li> <li>Restoration of one fixed-in-place metal window sash, including metal window frame, and hardware.</li> </ol> </li> <li>More than one mock-up may be required to be acceptable for approval. The Contractor shall prepare at least three mock-ups of each type (moveable and fixed), if required by the Architect, without further compensation. Approved test panels shall become part of the work and shall serve as the quality standard for all similar work.</li> </ol>

DELIVERY, STORAGE, AND HANDLING
<ol type="A"> <li>Deliver restoration materials and proprietary products to the project site in the manufacturer’s or distributor’s packaging, undamaged, complete with installation instructions. Store fillers, putties and cements within the temperature range recommended by the manufacturer and away from direct sunlight.</li> <li>Window sash and window frames that are removed from the site shall be labeled with all necessary information, including their window and register numbers and their location, to ensure reinstallation in the proper openings. They shall be covered and protected from damage by weather and construction activities.</li> <li>Window hardware components removed from individual frames and sashes shall be labeled prior to storage with detailed information, including window number, location on specific window, hardware type, and style number.</li> </ol>

PROJECT / SITE CONDITIONS
<ol type="A"> <li>The work of this Section is to be executed only when the air and surface temperatures are at least 40 degrees Fahrenheit.</li> <li>Do not undertake the restoration of windows until masonry restoration and masonry cleaning have been completed, if alternates for this work have been authorized. The Contractor shall coordinate work involving other trades so as not to delay the project schedule. In case of emergency repairs, the Architect will schedule the window(s) as first priority, before cleaning and masonry restoration.</li> <li>The Contractor is responsible for protecting existing adjacent materials during the execution of the work. Provide all necessary protection and work procedures to avoid damage to existing material assemblies not a part of the work of this Section. At a minimum, the Contractor shall: <ol> <li>During restoration work, protect from damage exterior wall surfaces, shutters, and window surrounds, and also interior walls and interior window features.</li> <li>Protect flashings and gutters, etc. when working on windows from the outside.</li> <li>Window openings from which the sash or larger window assemblies are removed shall be temporarily covered with plastic and secured with rigid material (3/4” plywood painted black) to prevent unauthorized access to the building. No holes or fasteners to exterior masonry units or decorative exterior or interior features shall be installed without prior approval of the Architect.</li> </ol> </li> <li>The Contractor shall be responsible for disposal of waste materials and other debris associated with the work of this Section in accordance with local, state, and federal environmental regulations. Architectural items can also be recycled or salvaged to reduce construction related waste. Three (3) examples of each salvaged window component shall be labeled as to the specific locations from which they came and delivered to the Architect upon completion of the project for archival purposes. The Architect shall also be shown the items intended for recycling or salvaging to determine which items, if any, shall be retained at the site for the benefit of future maintenance work on the building.</li> </ol> =PRODUCTS=

METAL WINDOW RESTORATION
<ol type="A"> <li>Replacement Glass: See Section 08800 – Glass and Glazing and, where applicable, Section XXXX – Specialty Glazing.</li> <li>Putty: Stiff, organic, oil-based glazier’s putty, or other glazing as approved by the Architect.</li> <li>Metal Filler: Architect to specify type of fillers to be used..</li> <li>Finishing: See Section 09900 – Painting and Finishing</li> <li>Hardware: Metal windows shall be furnished with complete sets of operable hardware. Where missing, damaged, or inappropriate previous replacements occur, new items shall be installed to match the historic hardware. When approved by Architect, hardware compatible with the historic character of the windows may be used instead as replacement for missing or damaged hardware.</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>The extent of the window restoration work shall be reviewed with the Architect on site prior to beginning operations. Contractor shall submit window schedule, including verified field dimensions and hardware inventory, prior to beginning work.</li> <li>Window sash should be removed from frames for repair as required. Window frames should be removed from window openings for repair as required, while taking necessary precautions against damaging the interior wall finish, window trim, and exterior walls.</li> </ol>

METAL FRAME AND SASH RESTORATION
<ol type="A"> <li>Test existing paint, caulk, and glazing compound for presence of any known hazardous materials; take appropriate remediation as needed.</li> <li>Carefully remove existing interior and exterior perimeter caulking materials. Remove, label and store hinges, handles, latches, glazing beads, and other hardware as required to undertake restoration work. Each shall be marked as to specific location within an individual window assembly where hardware is determined by either Architect or Contractor not be interchangeable.</li> <li>Wherepresent, rake interior and exterior glazing beads to remove cracked, loose glazing putty. Assume approximately 100% of glazing putty (interior and exterior) must be removed and replaced. Remove glass where it has come loose from putty. Where glass remains firmly seated in original full putty bed, it may be left in place.</li> <li>Remove paint buildup and any later applications of weather-stripping or sealants around operable sash that impede the operation of the windows. Clean metal sash, frames, and sub-frames, removing dirt, rust, putty, and loose paint. Use only cleaning methods approved by the Architect. Techniques to be used shall not damage historic finishes, existing metal frames, sash or window surrounds. Patch holes and corroded areas with specified epoxy compound.</li> <li>Straighten bent or twisted members as required, leaving sashes and frames flat, level, and true. Sashes should operate smoothly in frames and close completely without undue effort, leaving no gaps around the perimeter. Verify secure attachment of existing frame within the window opening. Tighten / re-anchor frame as required.</li> <li>Replace missing or badly deteriorate sections of the window using method or methods approved by the Architect..</li> <li>Restore historic finish or prepare, prime, and repaint all accessible surfaces as specified in Section 09900 – Painting and Finishing. Steel and iron window components shall be primed the same day they are cleaned to minimize oxidation.</li> <li>Re-glaze sashes as indicated, working putty into joints to form a full bed behind and beneath the glass. Reinstall glazing clips or beads where present to prevent lateral movement of glass before applying exterior putty bead. Tool glazing putty flush to ensure a continuous, waterproof seal, leaving a smooth, sloped surface and a neat, straight edge. Miter putty bead at corners.</li> <li>Clean salvaged hardware of accumulated grease, grime, paint spatters, and other soiling, avoiding any damage to existing historic finish that is to be retained. Lubricate all components as required to operate smoothly. When specified by Architect, polish or otherwise finish hardware to restore historic appearance; apply protective coating if specified. Reinstall in original locations, replacing missing or inappropriate screws and fasteners in kind as required.</li> <li>Where sash were removed for repairs, reinstall straight, plumb, and true in existing frames. Adjust as required to ensure smooth operation of sashes and verify functioning of hardware.</li> <li>Install backer rod as required and specified perimeter sealant at interior and exterior of window frame, tooling to achieve a smooth, concave profile. See Section 07900 – Sealants.</li> </ol>

FINAL REPORT
<ol type="A"> <li>Contractor shall provide a final report, including copies of approved submittals and photographs of the window work taken before, during, and after installation, and a written description of the executed work.</li> </ol>