Specification:Repair and rehabilitation of wood windows

__NUMBEREDHEADINGS__

=GENERAL=

SYSTEM DESCRIPTION
Repair wood windows as indicated, and return them to proper operation and sound condition.

SUBMITTALS
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation are for [Contractor Quality Control approval.] [information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government.] Submit the following in accordance with Section 01 33 00

SUBMITTAL PROCEDURES:
 * SD-02 Shop Drawings
 * Shop Drawings[; G][; G, [_____]]
 * SD-03 Product Data
 * Hardware
 * Weatherstripping
 * Qualifications
 * SD-04 Samples
 * Hardware
 * Moldings
 * Weatherstripping

QUALITY ASSURANCE
Provide qualified workers trained and experienced in repairing, restoring, replicating, and replacing windows in historic buildings; submit documentation of their Qualifications during 5 consecutive years of work of this type; and a list of installations made identifying when, where and for whom the installations were made. Submit Shop Drawings indicating elevations of units, full-size sections, fastenings, methods of installation and anchorage, method of glazing, locations of operating hardware, mullion details, method and material for weatherstripping, insect screen, details, connections with other work and window schedules showing location of each window unit. 

DELIVERY, STORAGE, AND HANDLING
Materials shall be stored out of contact with the ground and under weathertight covering. =PRODUCTS=

MATERIALS
Reuse existing materials whenever possible in the repair and rehabilitation of historic wood windows. This includes all wood elements, hardware and glazing that are determined to be of historic significance. Replace window elements with new material only when originals are so deteriorated as to prohibit their useful function.

WOOD
Wood used to replace deteriorated window members shall be of the same species and grade as the original, unless otherwise noted. Finger-jointed stock may be used for interior casing and trim only where scheduled to be painted.

GLASS AND GLAZING
Reuse existing intact original glass. Any removed lights shall be reused in their original frames and positions. New glass and glazing materials shall conform to Section 08 81 00 GLAZING.

HARDWARE
Reuse existing original hardware, when it is salvageable. Replacement hardware shall match original in design, material, and finish. Submit Manufacturer's installation instructions for each type of hardware and weatherstripping; see paragraph WEATHERSTRIPPING in PART 3. Submit representative sample of each type of hardware with identifying tags.

FASTENERS
Fasteners shall be stainless steel, galvanized, or non-ferrous metal.

GLAZING COMPOUND
Provide glazing compound for single pane glass which is oil-based, non-staining and non-bleeding. Existing insulated glass units shall be reglazed with silicone sealant complying with ASTM C1184 and compatible with the unit seal on the glass unit.

GLAZING POINTS
Glazing points shall be stainless steel or galvanized steel.

Liquid Consolidant
Liquid wood consolidant shall consist of a two-part, low-viscosity liquid epoxy that meets the criteria of Table A.

Epoxy Paste
Epoxy paste shall consist of a two-part, thixotropic paste that meets the criteria of Table A.

=EXECUTION=

EVALUATION
Perform a complete evaluation survey of the existing conditions of each wood window to determine the extent of repairs necessary. The evaluation survey may be in the form of a schedule and shall note at a minimum: Window location. Condition of the paint. Condition of the frame and sill. Condition of the interior and exterior trim. Condition of the sash (including rails, stiles, and muntins). Glazing problems.</li> Window hardware and operating system.</li> The overall condition of the window.</li> </ol>

Example Window
Prepare an existing window of each type to serve as an example of the quality of repairs to be provided for inspection and approval by the Contracting Officer.

Sash Removal
Remove the interior stops first, in a method so as to not scar the wood. Connecting hardware and operating mechanisms shall then be detached and the sash shall be removed from the frame. Identify removed sashes and frames as to location to assure reinstallation in their original positions. Windows with counter-weight systems shall have the sash cords detached from the sides of the sash and their ends pinned with a nail or tied in a knot to prevent them from falling into the weight pocket; the lower sash can then be removed. Remove the parting bead so as to not scar the wood. Install plastic covering or plywood to cover the window opening during repairs.

Paint Removal
Areas on frame, sill, sash and muntins where paint or varnish has peeled, alligatored, blistered or crazed shall have paint removed to bare wood or first sound paint layer, using non-destructive means such as a chemical stripper or heat gun. If chemical strippers are used, neutralize wood after stripping to a litmus pH of 5 to 8.5. Allow wood to dry to a moisture content of 8 to 12 percent before repainting. If heat methods are used for paint removal, protect glass from sudden temperature change to avoid breakage.

Wood Repair
Remove badly decayed areas (with more than 30 percent wood decayed) from wood sash, sill, frame, and trim assemblies. Moderately decayed areas (less than 30 percent decayed), weathered, or gouged wood shall be patched with approved patching compounds, and shall be sanded smooth. Intact sash rails and stiles that are loose shall be repaired with new dowels to make joints tight.

Epoxy Wood Repair
Apply epoxy wood repair materials in accordance with manufacturer's written instructions. Health and safety instructions shall be followed in accordance with the manufacturer's instructions. The source or cause of wood decay shall be identified and corrected prior to application of patching materials. Wet wood shall be completely dried to a moisture content of 8 to 12 percent to its full depth before patching. Wood that is to be patched shall be clean of dust, grease, and loose paint. Use clean mixing equipment to avoid contamination. Mix and proportions shall be as directed by the manufacturer. Batches shall be only large enough to complete the specific job intended. Patching materials shall be completely cured before painting or reinstallation of patched pieces.

Epoxy Liquid Wood Consolidant
Epoxy liquid wood consolidant shall be used to penetrate and impregnate deteriorated wood sections to reinforce wood fibers that have become softened or absorbent.

Epoxy Paste
Use epoxy paste to fill areas where portions of wood are missing such as holes, cracks, gaps, gouges, and other voids. Areas to receive epoxy paste patching material shall be primed with compatible epoxy liquid wood consolidant or a primer recommended by the manufacturer.

Wood Replacement
Replace pieces decayed beyond repair with new pieces that match originals in all respects. Joinery shall match that of existing. Muntins shall have coped mortise and tenon joints. Molded members shall have mitered or coped joints.

Hardware
Reuse existing hardware, which is in good condition, unless otherwise noted. Reused existing hardware shall be stripped of paint down to bare metal. Install new hardware where original is missing, damaged, or unsuitable for new operation, in accordance with manufacturer's directions to provide a secure and smoothly operating window assembly.

Glazing
Reinstall lights to be reused in their original frames and positions. Rabbeted integral glazing recesses shall be brushed with boiled linseed oil prior to the application of bed glazing compound. Replace broken glass as specified in Section 08 81 00 GLAZING.

Operating System
Repair windows with counter-weight systems to original operating function. Reuse original sash weights (and sash chains, if applicable) wherever possible. Missing weights and sash cords or chains shall be replaced. Missing or deteriorated sash cords shall be replaced with new cotton-polypropylene cord rated for sash weight. When new weights are required, they shall match the originals in weight. Replacement weights shall be cast iron or square milled steel bar stock.

Weatherstripping and Moldings
Install Weatherstripping on all operable windows. Weatherstripping shall consist of brass, compression or interlocking weather strips designed for permanent sealing under bumper or wiper action. Weatherstripping shall be provided at the perimeter of each sash including meeting rails and shall be installed in accordance with manufacturer's instructions. Submit a 300 mm 12 inch long sample of each type of weatherstripping required with fasteners. Weatherstripping shall be completely concealed when sash is closed. Install moldings in accordance with manufacturer's instructions. Submit a 300 mm 12 inch long piece of each molding type required for each window and casing with specified finish.

PAINTING PREPARATION
Areas where paint was removed or where existing paint shows crazing, wrinkling, and intercoat peeling shall be scraped, sanded, and shall have edges feathered. Remove paint to bare wood or first sound paint layer. All parts shall be cleaned by brush using bleach and/or trisodium phosphate (TSP) solution, and let dry. Existing finish shall be deglossed. Open joints and cracks shall be filled with epoxy repair materials. Perimeter of fixed sash shall be caulked.

PAINTING
Wood elements shall be primed and painted in accordance with Section 09 90 00 PAINTS AND COATINGS.

REASSEMBLY
After repairs are completed, the window shall be reassembled with all parts tight, true and functioning properly. Wood surfaces shall be free of blemishes.

ADJUSTMENTS
Make final adjustment, for proper operation of ventilating unit, after reassembly. Adjustments shall be made to operating sash or ventilators to assure smooth operation and weathertight performance when locked closed.

CLEANING
Windows shall be cleaned on both exterior and interior sides.