Sash Windows: Replacing a Sash Cord
A frayed sash-cord is dangerous; it creates the danger of sudden snapping which could lead to a nasty accident. Sash-cords should be inspected regularly and replaced immediately any signs of undue wear become apparent. To test a sash-cord for wear, lower the window to its full extent and pull the sash-cord away from the framework, when any worn patches will be easily seen. Any rusty marks on the sash-cord should be viewed with suspicion.
To renew a broken or frayed sash-cord necessitates removal of the sash; in the case of a lower sash it is only necessary to remove that particular sash (sash is just another name for this type of window). If the cords of the upper sash are damaged it will be necessary to remove both sashes. A plan of a sash window with the names of the parts is shown in the image below.
To remove a sash the sash, or staff bead should be eased away from the frame with a wood chisel. The chisel should be inserted midway on the sash beading to bow it away from the framework, to release the mitred corners. The beading at both sides should be removed. When this is done it will be found an easy matter to lift the sash from the frame.
If it is necessary to repair the cords of the upper sash, the parting bead between the two sashes should also be removed before the upper sash can be lifted out of the frame. This may be eased away from the frame by gently pulling with a pair of pliers and by using a wood chisel. The cords at both sides of the sash should be replaced even if only one is frayed or broken. Replacement of one cord only will automatically weaken the remaining cord. If one cord still holds the sash in place, it should be cut through with a sharp knife or a pair of side-cutting pliers.
The next part of the job consists of removing the sash weights, which are accommodated in pockets each side of the window-frame. Access to the weights for both upper and lower sashes is gained through an aperture in the window-frame which is covered with a trap. The trap is not nailed in position and it may be released from the framework by inserting a thin-bladed tool at the lower edge and gently levering it. With the trap released, the weights should be removed from the pocket inside the frame. The poundage of a sash weight and the thickness of the cord varies according to the weight of the window. The poundage of the sash weight will be stamped in the cast-iron weight and this poundage should be given when purchasing new cord to ensure that it is stout enough for the job it has to do.
Should one of the sash weights have tumbled into the cavity between the brickwork inside the window-frame in a position where it may not be recovered, the poundage of the opposite weight for the same window should be given when purchasing a replacement weight. After removing the sashes it will be seen that the sash-cord is attached each side of the frame. The method of attachment may vary and this may be secured by threading the sash through a slot in the side of the frame and knotting the end of the cord. Alternatively the cord may be secured in a groove at the side of the frame and fastened there with strong tacks.
Whatever the method of attachment to the sash, replacement should be done In exactly the same way. The length of the new piece of sash-cord may be reckoned by releasing all the knots and placing the two pieces of old cord together. Alternatively the length of the cord may be decided by measuring the amount of cord used in securing one end to the frame, measuring the distance between the top of the sash and the pulley, with the window positioned so that the cord is fully extended and making further allowance for the small amount of cord secured to the weight inside the framework.
The ends of the new cords should first be attached to the sides of the sash by knotting or tacking according to the design and the sash should be replaced in the frame. The cord is then passed over the pulley before securing it to the weights.
To facilitate the easy passage of the cord over the pulley and down inside the frame, use a line with a ‘mouse’. The mouse is simply a small strip of lead bent and hammered over the end of a stout line. The unloaded end of the line should be attached to the free end of the sash-cord. The lead mouse is then passed over the pulley, when it will drag the thin line down through the frame until the mouse can be seen in the open weight-cavity. The line is gently pulled over the pulleys until the cord is tightened. Before attaching the weights it is necessary to slide the window up as far as it will go inside the framework, the weight of the window should then be supported by an oval nail tacked firmly into the framework under the sash each side. The cord is then pulled tight and the free ends knotted to the weights.
The method of knotting is not really important, except that the knots should be made firm and the end of the cord should be passed under the loop from the hole in the weight so that the weight will not slip off the sash-cord. With this done the weights should be fitted into the cavity and the trap replaced. Thesupporting the sashes should be withdrawn from the frame before replacing the parting beading and/or the sash bead. Should the cords of both upper and lower sashes be renewed the upper sash should be dealt with before the lower one.
Finish the job by oiling the pulleys and retouching any damaged paint-work on the sash bead.