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Historic Preservation - Technical Procedures

Spectitle:

Unsticking A Wood Double-Hung Window Sash

Procedure code:

0861003R

Source:

Hspg Prepared For Nps - Sero

Division:

Doors And Windows

Section:

Wood Windows

Last Modified:

04/11/2014

Details:

Unsticking A Wood Double-Hung Window Sash



UNSTICKING A WOOD DOUBLE-HUNG WINDOW SASH


PART 1---GENERAL

1.01 SUMMARY
 
    A.   This procedure includes guidance and procedures required
         to inspect and loosen a wood sash.

    B.   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.

    C.   See 01100-07-S for "Ggeneral 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

    A.   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
         
    A.   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

    A.   A device for cutting paint seals such as "Window Zipper"
         (Red Devil), or approved equal; available at hardware
         stores.

    B.   A rubber mallet and block of wood for jamb and stop
         straightening

    C.   Utility knife for cutting paint seals

    D.   Paint scraper

    E.   Wide putty knife or "window zipper" to break paint seal

    F.   Screwdriver and screws to tighten jamb into place

    G.   Hand soap or household paraffin for waxing the stop and
         parting beads

    H.   Flat steel pry bar to loosen sash from outside

    I.   Carpenter's nippers to remove nails

    J.   1" chisel to scrape paint in channel

    K.   Sandpaper

    L.   Planer

    M.   Nail to secure sash cord/chain

    N.   Soap and water


PART 3---EXECUTION

3.01 EXAMINATION

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

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   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.

    B.   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.

    C.   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.

    D.   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.

    E.   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.

              a.   The sash must be carefully planed and should
                   be done only once.

              b.   Take off as little of the sash surface as
                   possible to make the window operable during
                   all times of the year.

              c.   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:

              a.   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.  

              b.   Pull one side of sash out to expose the sash
                   cord/chain.

              c.   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.
   
              d.   Remove loose paint from all members by
                   sanding, and repaint.

              e.   Reinstall parting bead and sash.

              f.   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.

              g.   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.

         3.   If weatherstripping applied too tightly is
              suspected to be the problem, removal and
              reinstallation of weatherstripping will be
              required.  

                             END OF SECTION
 


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