Closing Open Joints In Wood Wall Moldings

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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.



  1. This procedure includes guidance on closing an open joint in wood wall molding by removing and reinstalling or, when removal is not possible, by filling the piece.
  2. An open joint in wood wall ornament is usually the result of paint build-up. To repair an open joint, all excess paint must be removed. This procedure provides guidance ONLY for repairing open joints. See 06400-07-R, 06400-02-S and 06400-09-R for information on removal of paint from wood.
  3. 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 prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).



  1. Paint removal chemicals (if needed)
  2. Wood filler


  1. Utility knife or scraper to cut paint film
  2. 2 inch wide blade putty knives
  3. Hammer
  4. 2 prybars
  5. Nail puller
  6. Carpenter's nippers for nail heads
  7. Heat gun or plate for paint removal (see 06400-09-R for special precautions when using heat to remove paint from wood).
  8. Scraper or chisel for cleaning joint
  9. Saw to undercut miter
  10. Drill for possible pilot hole



  1. Surface Preparation: Adjacent surfaces and permanent equipment must be masked or covered during repair and maintenance. Coverings must be adhered without adhesive tape or nails. Impervious sheeting that produces condensation shall not be used.


NOTE: The repair of an open joint involves the removal and reinstallation of the molding, or the filling of open joints with wood filler. ONLY WHEN A JOINT CANNOT BE CLOSED SHOULD IT BE FILLED.

  1. Removing molding - Start at an inconspicuous corner. Cut paint build-up or wallpaper overlap between trim and wall.
    1. Insert two putty knives into edge of board to protect molding and wall. Carefully hammer the bent end of prybar between putty knives.
    2. Using wall as a fulcrum, work the molding away from the wall until a nail is spotted. Hold space open with another prybar or shingle and pry at location of nail. Continue until all nails are exposed and trim is loose. Remove trim by hand.
    3. If two moldings are attached to each other, carefully use two prybars against each other.
    4. Label all removed pieces so that they can be identified and reassembled properly.
  2. Cleaning molding - Remove all nails by pulling finish nails through the back of molding. Carefully cut the heads off larger nails and pull the remainder through the back.
    1. Remove paint from molding at joints with heat or chemicals (see 06400-07-R, 06400-02-S and 06400-09-R for guidance. Carefully scrape joint clean with chisel or scraper.
    2. If open joint is a miter, undercut miter at one or both pieces.
  3. Reinstalling molding - Temporarily position piece by nailing a finish nail half way in though existing nail hole.
    1. If position is correct, nail in place. Hammer the nail at a different angle through same hole. Use nailset to sink final few blows so as not to damage surface of wood.
    2. A new nail hole may be required if a piece is less than 5/8" thick. To avoid splitting, never nail within 2" of board end, blunt the head of the nail or snip it off, and/or drill a pilot hole.
  4. Filling open joint - If joint cannot be restored to its original position, remove as much paint as possible according to manufacturer's instructions. Fill gap with resilient wood filler and let dry. Add additional filler if shrinkage occurs and sand to achieve a smooth finish. Reapply finish.