Techniques > Systems > Windows > Conservation >

Repairing Double-Hung Window Sash Weights and Cords/Chains (08760-01)
Repairing Double-Hung Window Sash Weights and Cords/Chains (08760-01), Historic Preservation Technical Procedures, U.S. General Services Administration

Part 1 — General
1.01 SUMMARY

     A.   This procedure includes guidance on inspecting and
          correcting a faulty counter-balancing system.  This
          problem may be caused by a missing sash cord/chain, an
          unattached or missing sash weight, or a pulley in poor
          condition.

     B.   When a window sash will not stay open and slides back
          down to the closed position or when a window is difficult
          to slide, a faulty counterbalance system is often to
          blame.  

     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 prior to performing
          this procedure and should be followed, when applicable,
          along with recommendations from the Regional Historic
          Preservation Officer (RHPO).

1.02 DEFINITIONS

     A.   The counterbalance system in a double hung window is
          usually divided for the upper and lower sash.  Each
          system contains sash weights, sash weight pulleys, sash
          cord/chain, sash cord slot located in the stiles of both
          of the sashes, and the weight access pocket in the jamb 
          (Not in all double hung windows).  

1.03 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.
Part 2 — Products
2.01 MANUFACTURERS

     A.   Architectural Iron Co.
          Box 126, Schocopee Rd.
          Milford, PA 18337
          717/296-7722
          sash weights

     B.   Barry Supply Company
          36 West 17th ST.
          New York, NY 10011
          212/242-5200
          pulleys, sash weights, old hardware

     C.   Blaine Window Hardware, Inc.
          1919 Blaine Drive, R.D. 4
          Hagerstown, MD 21740
          800/678-1919 or 301/797-6500
          pulleys

     D.   Casting Unlimited
          P.O.Box 400
          Morris, NY 13808
          607/263-5194
          manufactures sash weights with your pattern or sample

     E.   Hern Iron Works
          1900 Millview
          Couer D'Alene,ID 83814
          208/765-3115
          sash weights; has patterns for most sizes, requires
          minimum order

     F.   The Woodstone Company
          P.O.Box 223, Patch Road
          Westminster, VT 05158
          802/722-3544
          sash manufacturer; will sell pulleys

2.02 MATERIALS

     A.   Sash cord/chain to replace existing cord/chain

     B.   Salvage sash weights if original ones are missing

     C.   1" PVC pipe and sand or leadshot to fabricate
          replacement sash weight if necessary

     D.   Pulley

     E.   Oil, motorcycle-chain lube or powdered graphite to
          lubricate pulley

     F.   Lye solution, or TSP is needed to remove paint from
          pulley

          1.   Trisodium Phosphate:  

               NOTE:  THIS CHEMICAL IS BANNED IN SOME STATES SUCH
               AS CALIFORNIA.  REGULATORY INFORMATION AS WELL AS
               ALTERNATIVE OR EQUIVALENT CHEMICALS MAY BE
               REQUESTED FROM THE ENVIRONMENTAL PROTECTION AGENCY
               (EPA) REGIONAL OFFICE AND/OR THE STATE OFFICE OF
               ENVIRONMENTAL QUALITY.

               a.   Strong base-type powdered cleaning material
                    sold under brand names.

               b.   Other chemical or common names include Sodium
                    Orthophosphate; Tribasic sodium phosphate;
                    Trisodium orthophosphate; TSP*; Phosphate of
                    soda*; (also sold under brand names such as).

               c.   Potential Hazards:  CORROSIVE TO FLESH.

               d.   Available from chemical supply house, grocery
                    store or supermarket or hardware store.

2.03 EQUIPMENT

     A.   Stiff putty knife

     B.   Small pry bar

     C.   Wide chisel

     D.   Wood screws

     E.   A "Pinpoint Oiler" which could be an aerosol can with an
          extension tube or a disposable glue syringe

     F.   A buffing machine 

     G.   See also 08610-03-R "Unsticking a Wood Double-hung Window
          Sash".
Part 3 — Execution
3.01 EXAMINATION

     A.   Check for the presence of a sash cord or chain.  If it is
          present and in proper working order, proceed to Section
          3.02 B.  If the old sash cord is missing, replace it. 
          Replace sash cord with cord; sash chain with chain.  In
          many cases, the hardware/pulleys may not be compatible
          with a change from chord to chain, or vise versa.

3.02 ERECTION, INSTALLATION, APPLICATION
     
     A.   To replace a sash cord/chain:

          1.   Remove the sash as outlined in 08610-03-R,
               "Unsticking A Wood Double-hung Window Sash".

          2.   Remove cord from slot in sash and ease the knot of
               the cord up towards the pulley, located in the
               jamb, until it stops and is held in place by the
               pulley.

          3.   Locate weight access door in the jamb and carefully
               remove it.  Remove weight from pocket and untie it. 
               Reserve weight.  If jamb does not have access door,
               or if access door has been covered with
               weatherstripping, the window trim will have to be
               removed to access weight pocket. 

          4.   Remove old sash cord/chain and cut a new cord/chain
               to match its length.

          5.   Secure one end of new sash cord/chain to window and
               thread other end over pulley into weight pocket.
               Attach cord/chain to weight and replace in pocket.
               Replace access door or trim.  

          6.   Pull cord/chain from other end until weight just
               touches pulley and temporarily secure the
               cord/chain and pulley in place with a nail threaded
               through a link across the pulley hole. 

          7.   Secure other end of cord/chain to slot in sash with
               2 wood screws.  Remove nail which is temporarily
               holding weight in up position.

          8.   Repeat procedure on other side of sash.  Reinstall
               sash and stops.

          9.   If sash cord/chain is missing altogether, pull
               weight up to pulley and temporarily secure it as in
               (6) above.  With the window in the closed position
               measure enough cord/chain so that the end can be
               screwed into the sash slot.  Cut cord/chain and
               continue as in (7) and (8) above.

     B.   Check if sash weight is unattached or missing:

          1.   Secure the sash in an open position. 
          
          2.   Locate and remove the weight access panel in the
               jamb. 

          3.   If weight is present but unattached, retrieve it
               and the end of the sash cord out of pocket and
               reattach.  Return them to pocket and replace access
               door.

          4.   If weight is missing or not retrievable, it must be
               replaced. Salvage is the first choice for
               replacement. If a salvage weight is unavailable or
               new sash weights cannot be easily purchased, a sash
               weight can be fashioned out of a 1-1/2" diameter
               PVC pipe with the end sealed and filled with sand
               or lead shot to the proper weight.

          5.   To determine size of sash weights:

               a.   Weigh the sash and divide by two

               -OR-

               b.   Use the following formula:  [(1#/sq.ft. glass)
                    + (height{ft.} x width{ft} x depth{in})]

     C.   Check condition of pulley.  Paint and dust build-up may
          be causing the pulley not to function properly.  

          1.   If pulley appears to be free from paint or dust
               build-up, re-lubricate the pulley using a pinpoint
               oiler to lubricate the wheel-and-axle surface.  

               -OR-

               Recondition the pulley:

               a.   Remove pulley from window frame.  It may be
                    attached by in one of two ways: two obvious
                    countersunk wood screws or friction fit.  Care
                    must be exercised when removing a friction fit
                    pulley because it is anchored in place with
                    hidden spurs.  Wedging a screwdriver between
                    the wheel and case will damage the pulley.

               b.   Paint can be removed from pulley by machine
                    buffing, soaking in a lye solution such as
                    oven cleaner or drain opener or trisodium
                    phosphate (TSP).

               c.   When paint and dirt are removed, re-lubricate
                    the wheel-and-axle surface as above and
                    reinstall.

                              END OF SECTION

 
.
  © 2002-2012 Heritage Stewardship     contact