Unsticking a Wood Double-Hung Window Sash

PART 1–GENERAL

1.01 SUMMARY

1. This procedure includes guidance and procedures required to inspect and loosen a wood sash.
2. A wood window sash can bind or stick for many reasons including: window nailed shut; accumulation of paint and/or dirt; humidity causing wood expansion; bowed members; weatherstripping too tight; or building settlement. NOTE: Some sash were fixed, installed without operable parts such as single hung sash.
3. See “General Project Guidelines” 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).

1.02 SYSTEM DESCRIPTION

1. A window sash in proper working order is freely sliding, has balancing and moving apparatus in working order, and has operable sash lock(s) to deter air infiltration. In addition, operable sash often have weatherstripping and adjustable interior stops to allow for seasonal swelling and shrinkage.

PART 2–PRODUCTS

2.01 MATERIALS

1. Replacement stock is available for stop and parting beads. Be sure replacement is an exact duplicate of the original. Milling a new piece may be required.

2.02 EQUIPMENT

1. A device for cutting paint seals such as “Window Zipper” (Red Devil), or approved equal; available at hardware stores.
2. A rubber mallet and block of wood for jamb and stop straightening
3. Utility knife for cutting paint seals
4. Paint scraper
5. Wide putty knife or “window zipper” to break paint seal
6. Screwdriver and screws to tighten jamb into place
7. Hand soap or household paraffin for waxing the stop and parting beads
8. Flat steel pry bar to loosen sash from outside
9. Carpenter’s nippers to remove nails
10. 1” chisel to scrape paint in channel
11. Sandpaper
12. Planer
13. Nail to secure sash cord/chain
14. Soap and water

PART 3–EXECUTION

3.01 EXAMINATION

1. Determine if sash is an operable design and not fixed.

3.02 ERECTION, INSTALLATION, APPLICATION

1. The sash may be nailed shut:
   1. Check around general area of sash for the presence of any nails.
   2. If sash is nailed shut with finish nails, drive them completely through with nailset.
   3. If large headed nails were used, pull them out with carpenter’s nippers being careful not to damage wood.
2. The sash may be painted shut:
   1. Break the paint seal between the stops and the sash.
   2. Use a “window zipper” or a wide putty knife with a rubber mallet.
   3. Do this on the inside and outside of the window.
   4. CAREFULLY insert a heavy screwdriver between the sash rail and jamb at groove for sash cord. TAKE CARE NOT TO MAR OR DAMAGE FINISH AND/OR SASH.
   5. Work at both sides of jambs to loosen sash.
   6. If window still will not open, use a pry bar on the outside of the sash. TAKE CARE TO PROTECT THE SASH AND SILL FROM DENTS WITH A WIDE PUTTY KNIFE OR WOOD BLOCKING. INTENSE PRESSURE ON A SMALL AREA SUCH AS THAT FROM A SMALL SCREWDRIVER OR FLAT PRYBAR CAN GOUGE OR DENT THE WOOD.
3. If the window has been opened but is difficult to move:
   1. Remove any dirt from the channel, stops, weatherstripping and parting bead.
   2. Remove any globs of dried paint from the stops and parting bead with a 1” chisel and sand edges after paint is removed.
   3. Lubricate stops and parting bead with hand soap or household paraffin.
4. If sash still binds, determine the point of friction:
   1. If the friction occurs along the jamb; with a hammer, tap a wood block approximately 6” long 5 or 6 times against the back of channel to force the jamb back into place. If this allows the sash to move more freely, screw the jamb into the jack stud behind at 3” intervals around the point of friction.
   2. If the friction occurs with the stop, use the same procedure as above, but with less force and do not drive screws into the stop.
5. Problems such as humidity, paint build-up, or weatherstripping applied too tightly require more aggressive repair:
   1. If the window is easily operable during dry times of the year but will not work properly during humid times, then humidity is to blame. Repair should not be attempted until the time of year with highest humidity. See section 1.02 A; If the window has adjustable interior stops, it may be desirable to refurbish and restore them to use.
      1. The sash must be carefully planed and should be done only once.
      2. Take off as little of the sash surface aspossible to make the window operable during all times of the year.
      3. Remove the sash as described below with the problem of paint build-up.
   2. If the sash binds because of the build-up of layers of paint, remove the paint. To remove the paint properly, first remove the sash:
      1. Remove the stop; break the paint seal between the inside stop and the window frame. Pry the stop away from the frame with a stiff putty knife, small pry bar, or wide chisel.
      2. Pull one side of sash out to expose the sash cord/chain.
      3. Remove cord/chain from both sides of sash. Temporarily secure the end of cord/chain with a nail through the cord/chain and across the pully hole so that it will not fall into the pocket. Lift out the sash.
      4. Remove loose paint from all members by sanding, and repaint.
      5. Reinstall parting bead and sash.
      6. When reinstalling inner stop, check position in relation to the sash one nail at a time so that sash will fit snugly in place and will not bind or rattle.
   3. To remove the upper sash - lower the sash; remove the parting bead from the top down; at midpoint, raise the sash and continue. Follow the same procedure as above.
      1. If weatherstripping applied too tightly is suspected to be the problem, removal and reinstallation of weatherstripping will be required.