Different parts of the window could be damaged, causing it to stick. You could have a damaged frame,or the window itself could be damaged. You could also have broken hardware, such as a metal catch or window lock being loose or out of place.

The best way to repair a stripped window crank is to replace the crank.

1. Pry off the original crank handle, using a screwdriver.
2. Turn the crank knob and push on the window at the same time to open the window, using pliers.
3. Push down on the crank arm to pop the wheel out of the track.

To unlock this type of window from the outside:

1. Find out if the window is open and push it with your hands. If this doesn’t work, place a prybar between the window and the windowsill.
2. Put the blade of a thin hacksaw in the window close to the latch.
3. Another way to open a locked sliding window is to break the lock.

Open up the window and locate the lock-adjustment head. Use an Allen wrench to turn the lock backward to increase the pressure it exerts on the window when it’s locked, which will create a tighter seal.

Regardless of what material your window is made of, there is no difference in the adjustment process. All steps are the same, meaning you can adjust uPVC windows the same way as aluminum or wooden ones. Old wooden frames often do not need to be adjusted.

If you have very large gaps around a window, you can fill them using expanding foam. Expanding foam is perfect for filling large gaps around windows as it allows for a degree of movement without cracking or breaking. It can also provide a good moisture barrier between the brickwork and the window frame.

If there is a gap between the sash and the frame on the hinge side, then it is your hinges. All that is wrong is that your hinges are after wearing down and not pulling the sash in tight against the frame anymore. Gap in window where hinge won’t close the sash fully.

While one person holds the window in place, the other slips shingle shims between the window and the rough opening to make sure the inside gap is even all the way around the frame. The gap should be about a 1/4-inch. Use a level to ensure the window unit is level and plumb.

Backer rod should be slightly larger than the void and fit snug into the void. Insert 3/8″ and 10 mm backer rod into the space around the window. Provide at least 3/8″ (10mm) clearance between the backer rod and the exterior face of the window.

Replace the old hinges by unscrewing them and putting the new hinges in place. Put the UPVC sash back into the frame and screw the new hinges in. Open and close the window a few times checking for gaps and making sure that opens and closes smoothly.

A rough opening refers to the framed opening of a window. A window frame, however, has a header across the top, a sill plate across the bottom, and vertical trimmers on either side. The difference between rough opening and actual window size will vary by manufacturer.