Double hung sash windows only need a few components to work smoothly. The most crucial are the weights.
A double hung sash window is made up of one or more moveable panes of glass. To facilitate operation, the weight of the glazed panel is usually balanced by sash weight or counter-weight concealed within the window frame. The sash weight is connected to the window by a braided cotton sash cord, or a chain, that runs over a pulley at the top of the frame.
As anyone in the Window Repair Industry will know, re-balancing windows is an integral part of a sash window service.
The largest percentage of the weight of a window sash is in the glazing, and the type of glass will therefore have a direct effect not only on the weight of the sash, but also on the required counterweight. For example, glass in older windows may well be 2mm thick, which was the standard of yester-year. In comparison the standard nowadays is 3mm thick which is heavier and will therefore require more weight to counterbalance it. If you have had new glass put in your window, and it is not functioning properly, chances are you need your window rebalanced.
Incorrectly balanced windows are at best awkward and difficult to use, at worst they are dangerous - if a heavy window drops from its closed position it could cause a lot of damage.
In the vast majority of cases, re-balancing windows requires adding more weight as opposed to taking weight away. ...Enter the "add-on weight".
Small, half pound or one pound weights are added to ensure the correct weight is counterbalancing the window.
Many add on weights on the market today in Australia are square. However, the existing weights in the windows that need to be added to are not square, they are round. Using our unique round and domed shape, our add on weights slot neatly and efficiently on to the existing weights making for a smooth and seamless movement within the box. They have been designed this way because we found square weights would often cause friction problems within the box.
Our weights come in half pound and one pound options.
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