Supplemental Guidelines For Specifying Repairs To Damaged Woodwork

Technical Procedures Disclaimer

Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.


We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.



A. This procedure provides supplemental guidelines to be used when specifying any type of repair to damaged woodwork. Guidelines for materials, fabrication and general guidelines for installation are included.

B. Specifications for the repair of woodwork shall include all work, materials and equipment required to:

  1. Carefully remove required woodwork and securely reinstall it to its original place and position. Use experienced riggers for the removal and transportation of woodwork.
  2. Repair woodwork to conservator quality standards.
  3. Document work done through photography.

C. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:

  1. Safety Precautions
  2. Historic Structures Precautions
  3. Submittals
  4. Quality Assurance
  5. Delivery, Storage and Handling
  6. Project/Site Conditions
  7. Sequencing and Scheduling
  8. General Protection (Surface and Surrounding)

These guidelines should be reviewed before performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).


A. American Society for Testing and Materials (ASTM),
100 Barr Drive,
West Conshohocken, PA 19428,
610-832-9585 or FAX 610-832-9555.


A. Wood Treatment Data: Submit chemical treatment manufacturers' instructions for handling, storing, installation, and finish of treated material.

  1. Non-Pressure Preservative Treatment: Include certification stating chemical solution and submersion period used and affirming compliance with indicated treatment standards.
  2. Fire-retardant treatment data for material impregnated by pressure process to reduce combustibility. Include certification by manufacturer that treated materials comply with requirements.

B. Restore twenty square feet or five linear feet (or quantity as appropriate) of each wood type to be restored for review by the RHPO before proceeding with all restoration. Where new wood must be used to match existing to repair or in fill damaged wood, install twenty square feet or five linear feet (or quantity as appropriate) in its final location for review by the RHPO before proceeding with all repair.

C. Shop Drawings: For new woodwork, submit shop drawings showing location of each item, dimension= al plans and elevations, large scale details, attachment devices and other components.

D. Quality Certification: Submit woodwork manufacturers' (fabricator's) certification, saying that fabricated woodwork complies with quality grades and other requirements suggested.

E. Field Measurements:

  1. Where woodwork is shown to be fitted to other construction, check actual dimensions of other construction by accurate field measurements before manufacturing woodwork; show recorded measurements before final shop drawings. Coordinate manufacturing schedule with construction progress to avoid delay of work.
  2. Where field measurements cannot be made without delaying the work, guarantee dimensions and proceed with manufacture of woodwork without field measurements. Coordinate other construction to ensure that actual dimensions correspond to guaranteed dimensions.


A. Installer Qualifications: Arrange for installation of architectural woodwork by a firm that can show successful experience in installing architectural woodwork items similar in type and quality to those required for this project.

B. Architectural Woodwork Institute (AWI) Quality Standard: Comply with applicable requirements of "Architectural Woodwork Quality Standards" published by the Architectural Woodwork Institute unless otherwise indicated.

C. Testing and Site Inspection: Conduct tests in the presence of the RHPO, using all procedures, materials and equipment needed to carry out the work.


A. Packing and Shipping: Do not deliver woodwork until painting, wet work, grinding, and similar operations that could damage, soil or deteriorate new woodwork have been completed in installation areas.

B. Storage and Protection: If woodwork must be stored in other than installation areas, store only in areas whose environmental conditions meet requirements specified in Section 1.06 Project/Site Conditions below.


A. Environmental Requirements:

  1. Provide adequate ventilation, use of respirators and protective clothing by workers, and sealing off work areas during the removal process.
  2. Woodwork manufacturer and installer shall advise contractor of temperature and humidity requirements for woodwork installation and storage areas. Do not install woodwork until required temperature and relative humidity have been stabilized and will be maintained in installation areas.
  3. Environmental Conditions: Obtain and comply with woodwork manufacturers' and installers coordinated advice for optimum temperature and humidity conditions for woodwork during its storage and installation. Do not install woodwork until these conditions have been attained and stabilized so that woodwork is within plus or minus 1.0% of optimum moisture content from date of installation through remainder of construction period.


A. Coordinate the work in this specification with appropriate work of other specifications to ensure proper scheduling for fabrication and installation of the work specified herein.

B. Verify all dimensions in the field before fabrication of all architectural woodwork to assure proper fit.



A. Wood Moisture Content: Provide kiln-dried lumber with an average moisture content range of 6% to 11% for interior work. Maintain temperature and relative humidity during fabrication, storage and finishing operations so that moisture content values for woodwork at time of installation do not exceed the above range.

B. Replacement Wood: Match species, grade, grain pattern, and other special characteristics of woodwork.

C. Provide wood blocking, anchorages and fasteners for above:

  1. Screws:
    • Select material, type, size and finish required for each use and as recommended by RHPO.
    • For metal framing supports, provide screws as recommended by metal framing manufacturer.
  2. Nails: Select material, type, size and finish required for each use and as recommended by RHPO.
  3. Anchors: Select material, type, size and finish required by each substrate for secure anchorage. Provide nonferrous metal or hot-dip galvanized anchors and inserts on inside face of exterior walls and elsewhere as required for corrosion resistance. Provide toothed steel or lead expansion bolt devices for drilled-in-place anchors. Furnish inserts and anchors, as required, to be set into concrete or masonry work for subsequent woodwork anchorage.

D. Fire-Retardant Materials

  1. Fire-retardant treated lumber shall be lumber and plywood with fire-retardant chemicals to comply with ASTM C20 and C27, respectively; provide materials which are pressure impregnated with fire- retardant chemicals and comply with the following requirements.
    • Fire-Retardant Chemicals: Use chemicals of type which do not bleed through or otherwise adversely affect finishes. Do not use colorants in solution to distinguish treated lumber from untreated lumber.
      1. Low Hygroscopic Type: Halogen and sulfate-free solution intended for interior applications not exposed to relative humidity more than 95%; with treated material having an equilibrium moisture content of not over 28% per ASTM D3201 at 92 =F1 2% relative humidity.
    • Available Products: Subject to compliance with requirements, products which may be incorporated in the work include, but are not limit= ed to, the following:
      1. "Dricon" (Koppers Co., Inc.).
      2. "Flameproof LHC" (Osmose Wood Preserving Co. of America, Inc.).
      3. "Protex" (Hoover Universal, Wood Preserving Division).
  2. Fire Performance Characteristics: Provide materials which are identical to those tested per ASTM methods and are marked and listed for fire performance characteristics by Underwriters Laboratories, Inc. or other testing and inspecting agency acceptable to authorities having jurisdiction, and comply with the following requirements:
    • Mill lumber after treatment, within limits set for wood removal that does not affect listed fire performance characteristics, using a woodworking plant certified by testing and inspection agency.
    • Marking: Identify treated lumber with separable paper classification marking of inspecting and testing agency, unless otherwise indicated.
    • Surface Burning Characteristics: Not exceeding values shown below, tested per ASTM E84 for 30 minutes with no evidence of significant combustion.
      1. Flame Spread: 25.
      2. Smoke Developed: 50.
    • Kiln-dry woodwork after treatment to levels required for non-fire-retardant woodwork materials. Maintain moisture content required by kiln drying, before and after treatment.
    • Discard treated lumber that does not comply with requirements of referenced woodworking standard. Do not use twisted, warped, bowed, discolored, or otherwise damaged or defective lumber.


A. Wood Moisture Content: Comply with requirements of referenced quality standard for moisture content of lumber in relation to relative humidity conditions existing during time of fabrication and in installation areas.

B. Fabricate woodwork to dimensions, profiles, and details provided and approved by RHPO.

C. Complete fabrication, including assembly, finishing and hardware application, before shipment to project site to maximum extent possible. Disassemble components only as necessary for shipment and installation. Where necessary for fitting at site, provide ample allowance for scribing, trimming, and fitting.

D. Wood Surrounds and Trim: Fabricate to profiles required in single lengths for jamb and head conditions. Provisions for securing through face of trim shall include plugs to match surface.

E. Factory-cut openings, to maximum extent possible, to receive hardware, appliances, plumbing fixtures, electrical work, and similar items. Locate openings accurately and use templates or roughing-in diagrams to produce accurately sized and shaped openings. Smooth edges of cutouts and, where located in countertops and similar exposures, seal edges of cutouts with a water-resistant coating.

F. Measurements: Before proceeding with fabrication of woodwork required to be fitted to other construction, obtain field measurements and verify dimensions and shop drawing details as required for accurate fit.

  1. Where the sequence of measuring substrates before fabrication would delay the project, continue with fabrication (without field measurements) and provide ample borders and edges to allow for subsequent scribing and trimming of woodwork for accurate fit.

G. Preservative Treatment by Non-Pressure Method: Comply with requirements of referenced woodworking standard for non-pressure treatment of woodwork with non-aqueous water repellent solution, except as indicated. Treat units of woodwork after cutting, machining, sanding, gluing and assembling has been completed to the greatest extent possible. Coat surfaces cut after treatment with heavy brush coating of same preservative.



A. Conserve as much of the original material as possible, repairing and restoring damaged existing woodwork rather than replacing it wherever practicable. Use salvaged material where practical in spaces with some existing woodwork to remain. If not practical, replace all woodwork with new materials that replicate the existing items; maintain RHPO approval.

B. Do a thorough examination of the existing wood condition. Do any necessary tests on an inconspicuous surface to learn the current condition and appropriate steps and materials necessary for restoration of all existing wood surfaces.


A. Protection:

  1. Protect adjacent surfaces with polyethylene covers during wood removal operations.
  2. Protect persons and surrounding surfaces of building interiors whose wood surfaces are being restored from damage resulting from wood restoration work.

B. Surface Preparation:

  1. Condition woodwork according to average prevailing humidity conditions in installation areas before installing.
  2. Before installing architectural woodwork, examine shop-fabricated work for completion and complete work as required, including back priming and removal of packing.
  3. Pre-Installation Meeting: Meet at project site before delivery of architectural woodwork and review coordination and environmental controls required for proper installation and ambient conditioning in areas to receive work. Include in meeting the contractor; RHPO, contracting officer, and other owner representatives (if any); installers of architectural woodwork, wet work such as plastering, other finishes, painting, mechanical work and electrical work; and firms or persons responsible for continued operation (whether temporary or permanent) of HVAC system as required to maintain temperature and humidity conditions. Proceed with woodwork installation only when everyone concerned agrees that required ambient conditions can be maintained.
  4. Deliver concrete inserts and similar anchoring devices to be built into substrates, well ahead of time substrates are to be built.


A. General:

  1. Quality Standard: Install woodwork to comply with AWI Section 1700 for type of woodwork involved.
  2. Carefully remove at locations indicated any damaged or deteriorated woodwork. Unless indicated otherwise, replace the entire length of the existing damaged piece to the next butt joint.
  3. For partial replacement of existing pieces, use a neat, well-fitted level cut with grain aligned in transparent finish wood.

B. Replacing Deteriorated Material: Install new pieces as follows:

  1. Install the work plumb, level, true and straight with no distortions. Shim as required using concealed shims. Install to a tolerance of 1/8" in 8'-0" for plumb and level; and with 1/16" maximum offset in flush adjoining surface, 1/8" maximum offsets in revealed adjoining surfaces.
  2. Cut to fit unless specified to be shop-fabricated or shop-cut to exact size. Where woodwork abuts other finished work, scribe and cut for accurate fit. Before making cutouts, drill pilot holes at corners.
  3. Standing and Running Trim: Install with minimum number of joints possible, using full-length pieces (from maximum length of lumber available) to the greatest extent possible. Stagger joints in adjacent and related members. Cope at returns, miter at corners, and comply with Quality Standards for joinery.
    • Reuse salvage material as required. Use only trim that can be reinstalled and refinished to an acceptable condition consistent with the existing trim to remain.
    • Where salvage material will not match existing, remove and replace with new to replicate existing.
  4. Anchor woodwork to anchors or blocking built-in or directly attached to substrates. Secure to grounds, stripping and blocking with countersunk, concealed fasteners and blind nailing as required for a complete installation. Except where pre-finished matching fasteners heads are required, use fine finishing nails for exposed nailing, countersunk and filled flush with woodwork, and matching final finish where transparent finish is suggested.
  5. Finish replacement woodwork to match adjacent woodwork surfaces.


A. Upon completion of this work, all floors, walls and other adjacent surfaces stained, marred, other= wise damaged by work under this section shall be cleaned and repaired and all work and the adjacent areas shall be left in a clean and perfect condition.

B. All completed work shall be adequately protected from damage by subsequent building operations and effects of weather. Protection shall be by methods recommended by the manufacturer of installed materials and as approved by the RHPO.

C. Repair damaged and defective woodwork wherever possible to eliminate defects functionally and visually; where not possible to repair properly, replace woodwork. Adjust joinery for uniform appearance.

D. Clean woodwork on exposed and semi-exposed surfaces. Touch up factory-applied finishes to restore damaged or soiled areas.


A. Protect work of other trades, whether to be restored or not, against damage by restoration work. Correct any damage by cleaning, repairing or replacing, as acceptable to RHPO. At completion of work of other trades, restore all damaged or defaced surfaces.

B. Provide final protection and maintain conditions in a manner acceptable to manufacturer and installer, that ensures that woodwork is being without damage or deterioration at time of substantial completion.