When a double-hung window is stuck and cannot be opened, the trouble is either caused by dampness which causes the sash to swell or to paint that has been applied improperly and has sealed the window to its stop. Freeing a stuck window is not a difficult task, but the methods used depend to some extent on the cause.
If a sash is stuck because paint has hardened, joining the sash to a stop or to the sill, it is necessary to break the paint seal. Use a putty knife, if you have one, or any other thin blade, and insert it between the sash and the stop. Tap the blade lightly with a hammer, and simply cut the paint. Alternatively, you can force a chisel or a hatchet blade between the bottom of the window and the frame from outside. As you tap on the back of the hatchet or the handle of the chisel, the taper forces the window open breaking the paint seal. Once the window has moved, it usually can be opened easily. Scrape away the extra paint so that the window will not jam again when it is closed. If you wish, you can sand the edge to make it smooth. If none of these methods are effective, you must remove the inside stop and free the window in the same manner as before by replacing a sash cord. Pry off the stop carefully, since you will be breaking the paint seal as you do.
When a sash sticks because of dampness, you can sometimes loosen the widow by hammering the stop away from the sash. Use a small block of wood between the hammerhead and the stop so that you do not mar the stop. Again, if this method is ineffective, you can free the window by removing the inside stops and the sash. If the sash moves stiffly without the stop in place, it indicates that the sash itself is swollen. Remove the sash, plane or sand the edge so that it moves freely. Before putting it back, rub the edge with paraffin or wax. This lubricates the sash so that it slides better and also forms a seal against moisture.
When steel casement windows are difficult to more, the trouble may be due to excessive paint but is most often caused by inadequate lubrication. Oil all moving parts at the first sign of sticking. Sand off any rust spots, and touch up with a rust-resistant primer. Break paint seals by moving the window back and forth a few times and scrape away any accumulated layers of paint.
