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Historic Preservation - Technical Procedures

Spectitle:

Repairing Double-Hung Window Sash Weights And Cords/Chains

Procedure code:

0876001R

Source:

Hspg Prepared For Nps - Sero

Division:

Doors And Windows

Section:

Window Hardware

Last Modified:

02/24/2012

Details:

Repairing Double-Hung Window Sash Weights And Cords/Chains



REPAIRING DOUBLE-HUNG WINDOW SASH WE= IGHTS AND CORDS/CHAINS


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 Precaution= s

         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<= br>
    C.   1=AB" PVC pipe and sand or leadshot to fabric= ate
         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.  REGU= LATORY INFORMATION AS WELL AS
              ALTERNATIVE OR EQUIVALENT CHEMICALS MAY BE
              REQUESTED FROM THE ENVIRO= NMENTAL 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
                   Ortho= phosphate; Tribasic sodium phosphate;
                   Triso= dium orthophosphate; TSP*; Phosphate of
                   soda*; (also sold under brand names such as).

              c.   Potential Hazar= ds:  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 tempor= arily 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.  Remo= ve 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 unatt= ached, 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 followi= ng 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
                   attac= hed by in one of two ways: two obvious
                   count= ersunk 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
                   buffi= ng, soaking in a lye solution such as
                   oven cleaner or drain opener or trisodium
                   phosp= hate (TSP).

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

                             END OF SECTION