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 |
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