Specification:Wood window restoration

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=GENERAL=

DESCRIPTION
 This specification provides guidance for the repair of wood windows. This specification has been developed for use on historic properties (defined as any district, site, building, 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 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 outlined 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. Site-specific specifications, when appropriate, will be provided by the Architect. 

SECTION INCLUDES
 Wood Window Repair and Restoration</li> </ol>

RELATED SECTIONS
<ol type="A"> 06200 – Finish Carpentry</li> 06220 – Millwork</li> 06300 – Wood Treatment</li> 07900 – Sealants</li> 08800 – Glass and Glazing</li> 09900 – Painting</li> </ol>

SUBMITTALS
<ol type="A"> Window Schedule: Submit a detailed schedule 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: Submit manufacturer’s product literature to architect for all proprietary products specified for treatment. Product literature shall include specification data, Material Safety Data Sheets and instructions for storage, handling and use.</li> Submit supplier’s certification for graded but unmarked lumber or plywood attesting that materials meet the grade requirements.</li> Samples:  Submit one 12 inch length of each wood molding profile required.</li> Submit one sample of each type of new hardware item to be used.</li> Submit one 12 inch sample of each type of weatherstripping required.</li> </ol> </li> </ol>

QUALITY ASSURANCE
<ol type="A"> The Contractor shall have a minimum of seven (7) years experience in repair and restoration of wood windows. He/she shall have successfully completed at least three window restoration projects of similar scope within the previous five years.</li> The Contractor shall provide the following warranties for window repairs: <ol> <li>Ten (10) year warranty on materials and workmanship.</li> </ol> </li> </ol>

MOCK-UPS
<ol type="A"> <li>The Contractor, at locations determined by the Architect, shall prepare mock-ups of the following work: <ol> <li>Restoration of one double-hung wood window assembly.</li> </ol> </li> <li>Mock-up shall demonstrate the full range of restoration techniques required to complete the project. Techniques include epoxy consolidation, dutchman repairs, glazing, painting and installation of sealants (See Sections 06250, 07900 and 09900).</li> <li>Completed repairs shall be inspected and approved by the Architect prior to completion of the painting mock-up at the same window. Coordinate repairs with sealant installation and finishing by Painting Contractor.</li> <li>More than one mock-up may be required to be acceptable for approval. The Contractor shall prepare up to three mock-ups of each type, if necessary, 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 manufacturer’s original packaging, undamaged and 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 sashes 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.</li> <li>Window hardware components removed from individual frames and sashes shall be labeled prior to storage with detailed information including window number and location and hardware type and style number to facilitate installation on the proper window units.</li> <li>Store epoxy-based wood consolidants and fillers indoors in a cool, dry location away from direct sunlight. Ensure that products remain within the temperature range specified by the manufacturer.</li> <li>Store millwork materials off the ground, under cover and protected from weather and construction activities.</li> <li>The Contractor shall dispose of all waste materials, packaging and debris in accordance with local, state and federal environmental regulations. No burning of debris shall be allowed on site.</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 cleaning have been completed. The Contractor shall coordinate work involving other trades so as not to delay the project schedule.</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>Protect masonry and interior window surrounds and walls during adjustment or removal of existing window sashes and frames.</li> <li>Protect flashings & gutters, etc. when working on windows from the outside.</li> <li>Window openings from which sashes 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 the masonry may be installed without prior approval of the Architect.</li> <li>Protect finished floors and trim in work areas from nicks, scratches and mechanical damage during window removal and reinstallation. Remove furnishings from the immediate work area.</li> </ol> </li> <li>All window materials that are removed for repair shall be labeled appropriately, stored on site and protected from physical damage and moisture.</li> </ol> =PRODUCTS=

WOOD WINDOW REMOVAL
<ol type="A"> <li>Materials <ol> <li>Chemical softening agent / stripper</li> </ol> </li> <li>Equipment <ol> <li>Heat plate</li> <li>Heat gun</li> <li>Torch</li> <li>Hand tools – scrapers, putty knife, screwdriver</li> </ol> </li> </ol>

WOOD WINDOW RESTORATION
<ol type="A"> <li>Replacement Glass: See Section 08800, Glass and Glazing.</li> <li>Putty: Stiff, organic, oil-based glazier’s putty. Acrylic glazing putty may be used if accelerated cure and finishing is required.</li> <li>Epoxy Consolidant: See Section 06300.02 Historic Wood Structural Repair and Dutchman Patching</li> <li>Adhesives and Fillers: <ol> <li>Wood Glue: Carpenter's (white) glue as approved by the Architect..</li> <li>Epoxy filler for consolidated woodwork to be painted: Non-shrinking, moisture resistant, paintable structural adhesive putty and wood substitute approved by the Architect.</li> </ol> </li> <li>Wood sash, mullions and frame (for repair see Section 06300.02, Historic Wood Structural Repair and Dutchmen)</li> <li>Nails and Fasteners: Provide nails and screws of the types and sizes required to adequately secure the work. Fasteners shall be of material and finish appropriate for the intended use. Hot-dip galvanized fasteners shall be used for work to be exposed to the exterior.</li> <li>Finishing: See Section 09900, Historic Finishes</li> <li>Hardware <ol> <li>Windows shall be furnished with complete sets of operable hardware. Where missing, damaged or inappropriate previous replacements occur, new items shall be installed.</li> <li>See Section 08750, Historic Windows – Hardware and Fittings</li> </ol> </li> </ol>

WOOD MATERIALS
<ol type="A"> <li>Wood components and dutchman patches for repair of existing windows and frames shall match the species of the components being repaired.</li> <li>New wood for exterior trim applications shall be one of the following: <ol> <li>Long leaf yellow pine</li> <li>Cedar or Spanish Cedar</li> <li>Plantation grown Honduras Mahogany. Only plantation grown materials will be accepted.</li> </ol> </li> <li>Moisture Content <ol> <li>Trim and Millwork 1¼ inches or less in nominal thickness: 12 percent.</li> <li>Untreated Finish Lumber and Trim 4 inches or less in nominal thickness: 15 percent.</li> <li>Other Wood Products: Moisture content shall be within the ranges allowed by applicable woodworking standards.</li> </ol> </li> </ol>

WEATHERSTRIPPING
<ol type="A"> <li>Sill, Head, Meeting Rail and Jambs: Bronze rib strip, Cushion or “V” bronze depending on jamb configuration.</li> <li>Install bronze weatherstrip using bronze nails or screws as recommended by the manufacturer.</li> <li>Bronze weatherstripping shall be approved by the Architect.</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>Windows shall only be replaced in their entirety when they are either missing or beyond repair. It is important to remember that windows often play a major role in the historically contributing features, and, consequently, window repairs should be carefully planned. Removal of historic windows may alter a building’s contributing status on the National Register of Historic Places. Epoxy consolidation, splicing/patching or use of Dutchmen is preferable to outright replacement. The extent of all repairs and suggested replacements must be approved by the Architect.</li> <li>Provide epoxy consolidation and patching for sections of deteriorated wood with a volume of less than 4 cubic inches.</li> <li>Use Dutchman repair / splicing to replace sections of deteriorated wood with a volume of more than 4 cubic inches but extending less than 1/3 the length of the member.</li> <li>Completely replace severely deteriorated members, especially those with extensive deterioration at joints.</li> </ol>

REMOVAL OF DETERIORATED ELEMENTS
<ol type="A"> <li>Remove paint, beginning with the interior frames, the interior stop and parting beads. If necessary, use approved chemical strippers and/or heat treatments. Because the glass may be historic, protect glass from heat sources to avoid glass breaks. It can be removed or covered with aluminum foil, gypsum board, or asbestos.</li> <li>Remove stops and, if necessary, casing. Avoid gouges to casing and frames during removal of stops.</li> <li>Remove sash. Label each window clearly to ensure replacement in correct opening.</li> <li>Manually remove glazing putty and glass. Stubborn putty can be removed from the wood using a soldering iron. Glass can be soaked in linseed oil for putty removal.</li> <li>Label each window element (incl. each pane if they are to be salvaged) so that it can be placed in its original location.</li> <li>Remove all hardware. As needed, store hardware in cloth bags labeled with window number. Repair or replace as necessary (for repair see Section 05000, Historic Metals).</li> <li>Remove interior stops and parting beads for repair or replacement as necessary.</li> </ol>

REPAIR AND REINSTALLATION
<ol type="A"> <li>Repair <ol> <li>Repair structural defects and surface damage to the wood using epoxy approved by the Architect. See Section 06300.02, Historic Wood Structural Repair and Dutchmen.</li> <li>Stabilize damaged window joints with new hardwood dowels, set in place with epoxy. Replace sections or elements of the sash, as needed. Use select, new or salvaged first grown pine or similar for replacement stock if available.</li> <li>Treat heavily checked, weathered and abraded wood surfaces to remain with epoxy consolidant and epoxy wood filler as specified in Section 06300.02. Fill large holes and gouges flush with adjacent surfaces. Tool epoxy fill material to match existing molding profiles.</li> <li>Replace all missing, broken and unusable parts with new wood components of the same wood species. Match existing work in profile, size, arrangement and character. Secure new parts to existing material using glue and acceptable concealed fasteners in a rigid and secure manner.</li> <li>Sand all surfaces to a uniform finish and wipe down with mineral spirits/linseed oil.</li> <li>Prime all glass bedding surfaces in dust free location using oil based primer. Set glazing in full putty bed and secure with glazing points. Fix with glazing compound and allow glazing compound to dry until skinned over.</li> <li>Apply primer to all surfaces and allow to dry. Apply finish latex paint to all surfaces. Two coats are recommended.</li> <li>Clean all glass.</li> </ol> </li> <li>Reinstallation <ol> <li>Install all new work plumb, level, true and straight with no distortions. Shim as required using concealed shims. Install to a tolerance of 1/8 inch in 8 feet for plumb and level and with no variation in flushness. Notify Architect where woodwork cannot be set plumb and/or level due to existing field conditions before proceeding with the work.</li> <li>Anchor woodwork to blocking built-in or directly attached to substrate. Secure to grounds, stripping and blocking with countersunk, concealed fasteners and blind nailing as required for a complete installation. Use fine finish nails for exposed nailing, countersunk and filled flush with woodwork.</li> <li>Reinstall sashes, stops and trim and install new woodwork as required in a neat and workmanlike manner with accurate and tight-fitting joints. All nail heads shall be set below the surface. Dents, splits, gouges, hammer marks and other defects are not acceptable and shall require replacement of the member. Sashes shall slide smoothly and freely.</li> <li>Scribe all new trim and millwork to adjacent surfaces. Joints between woodwork and masonry shall be no greater than ¼ inch. Where woodwork must be scribed to fit adjoining work, prime cut surfaces or repair damaged finish at cuts.</li> <li>Lightly sand the sides of the vertical sash rails and inside of the jambs. Apply a wood sealer to these surfaces.</li> <li>Prepare all operational surfaces, removing paint build up. Fabricate and install new parting beads if required.</li> <li>Reinstall sash in a lubricated track.</li> <li>Touch up paint as necessary.</li> <li>Reinstall new or restored hardware, interior stops, weatherstripping, and sash. Replace sash cords as required. Use solid bronze sash chain unless otherwise specified. See Section 08750 Hardware and Fittings.</li> </ol> </li> </ol>

FINAL REPORT
<ol type="A"> <li>After completion of the window repair work, the Architect shall submit a final report including copies of approved submittals, initial assessment of historic wood window condition, photographs taken before, during, and after repair treatments, and a written description of the executed work.</li> <li>The Architect shall include a written proposed maintenance program to avoid unnecessary loss of historic fabric in the future.</li> </ol>