How to Correctly Add More Weight to Your Sash Window
How to correctly re-balance your double hung sash window
1. Remove the sash window
2. Remove the weights. The weights are housed inside the boxed frame behind a pocket which is removable once the parting bead has been taken out. Untie the cord holding the weight, pass the cord through the pulley and remove the sash weights.
3. TOP SASH: Weigh the window. Ideally the weights for the top sash need to be slightly heavier than the window itself so that it doesn't drop down when it is open. Weigh your window on scales - bathroom scales will do! Add one pound (approx. 0.46kg) to the total and then divide this number by two. That is the weight that goes on either side of the window.
4. BOTTOM SASH: Weigh the window as above. This time take the total and then divide this number by two. That is the weight that goes on either side of the window.
5. Tie a piece of string with a small weight added to the end of the new sash cord. Thread the string through the pulley and pull through into the boxed frame. Add the new weights to the cord, but make sure you tie a knot in the cord so that it doesn't get pulled back through the sash pulley once the new weights have been added.
6. Re-attach the window . Place the new window back in the frame. This might need two people as the cord will need to be pinned (using galvanised nails) into the new window