Sash Leaks:
When the leak is from a sash it is usually from the top and is caused by the hinge stays not pulling the sash in tight enough to get a good seal replacing the hinges will normally fix this or depending on the type of joinery the sash top sealing rubber has shunk back and needs replacing not all sashes have a top seal.

Sliding window leaks can be caused by lack of drainage from the track area. Sliding window felts been worn or none existant. The sliding panel not sitting square and not sealing possibly the wheels. If its leaking from the fixed pane then it requires the glass to be removed and the frame resealed. The glazing rubbers are normally replaced at this time.

Sliding door leaks can be caused by lack of drainage from the track area. Sliding door felts been worn or none existant. The sliding panel not sitting square and not sealing possibly the wheels. If its leaking from the fixed pane then it requires the glass to be removed and the frame resealed. The glazing rubbers are normally replaced at this time.