The whole door, not just one part
A sliding door is a system: the panels, the lock, the handles, the seals and the glass all have to work together. When one part fails, the others suffer. A lock that does not line up gets forced, a forced lock damages the handle, and a door that will not close properly lets in the weather. This page is about the door as a whole, and getting it to close, seal and lock properly again.
Doors that will not lock, or are hard to lock
The most common complaint is a door that closes but will not lock, or locks only when you lift it or lean on it. Usually the hook on the door and the keep on the frame no longer meet, because the panel has shifted or the keep has worked loose. Sometimes the lock body itself is worn inside. We check which it is, realign the keep and the panel, and replace the lock if the mechanism has failed. A door you cannot lock is effectively an open door, so this is worth doing promptly.
Locks, handles and key cylinders
Handles crack, pulls come loose and key cylinders wear until the key sticks or turns without throwing the lock. These parts are replaced to suit the door, and a night latch or key cylinder can be added to a door that only has a basic catch.
Seals and draughts
Sliding doors seal with brush strips and rubber along the edges where the panels meet and where they close against the frame. When these wear flat, you get draughts, dust, insects and rain blown in along the edges. New seals are fitted into the existing channels.
Cracked or broken glass
Glass in a door takes knocks from furniture, pets and people who do not see it. A cracked panel should be replaced rather than taped and left, because the door is opened and closed every day and a cracked pane can give way. For door glass we recommend laminated safety glass, which holds together if it is ever broken again. The options are set out on our window glass replacement page.
Alignment and adjustment
Over time a door panel drops or leans, the gap between panel and frame becomes uneven, and the door catches at one end. Adjusting the panel's height and level brings it back into line so it closes square and seals evenly. If the door is hard to slide rather than hard to close, the cause is underneath the panel, and our page on sliding door rollers and tracks deals with that separately.
Hinged and stacking doors too
The same care applies to hinged aluminium doors, which drop on their hinges and scrape the floor or catch the frame, and to stacking doors, where one panel out of line stops the whole set folding. Hinges are adjusted or replaced, and stacking panels are realigned so they fold, close and lock in order.
Repair or replace?
Repair is almost always the answer when the frame is straight and square. Consider a new door when the frame is bent from a break-in or impact, when parts for an old system cannot be matched, or when you want larger panels or a different type of door; see aluminium sliding doors for the options. For sliding doors in wood or steel, see sliding door repairs.