Fix a sliding patio door that sticks

Clean, adjust and lubricate a sticking sliding patio door so it runs smoothly and latches properly again.

PD-01Work out what's causing the stickSlide the door fully open and closed a few times, paying attention to where it drags. Note whether it sticks along the whole track, jams in one spot, or feels heavy from the very start. This tells you whether the fault is dirt in the track, worn rollers, or the door sitting unevenly in its frame, so you know which of the later steps to focus on.

PD-02Clear debris from the trackVacuum the track with a nozzle attachment to lift out grit, sand and dead insects. Use an old toothbrush to get into the corners and the groove itself. Wipe the track dry with a cloth. A single small stone or a build-up of grit is the most common reason a patio door sticks.

1 each · Old toothbrush

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1 each · Microfibre cloth

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PD-03Check the rollers for wear or damageMost sliding patio doors run on small wheels (rollers) fixed to the bottom of the door. Tilt or gently lift the door slightly to see them without removing the whole door if you can. Look for flat spots, cracks, or a roller that doesn't spin freely by hand. Patio doors are heavy and awkward, so get someone to help you support the door if you do need to lift it clear of the track.

PD-04Adjust the roller heightFind the adjustment screws, usually at the bottom corners of the door, sometimes under a small plastic cap or reached through a hole in the frame edge. Turning a screw clockwise usually raises that corner of the door, anticlockwise lowers it. Make small quarter-turns and test the door after each one until it slides evenly without rubbing the frame or track.

1 each · Screwdriver (flat or Phillips, check your door)

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PD-05Lubricate the track and rollersUse a dry PTFE-based lubricant spray, not oil or grease, which attracts more dirt and makes sticking worse over time. Spray lightly along the whole track and onto the rollers, then wipe off any excess with a cloth. Slide the door back and forth a few times to work the lubricant in.

1 can · PTFE dry lubricant spray

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PD-06Check the door sits square in the frameWith the door closed, look along the gap between the door edge and the frame at the top and both sides. An uneven gap means the door is sitting slightly twisted. Go back to step PD-04 and fine-tune the roller adjustment on the side that's out. If the gap stays uneven after adjustment, the roller on that side is likely worn out and needs replacing.

1 pair · Replacement roller set (if worn)

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PD-07Adjust or clean the latch and keeperIf the door now slides smoothly but won't latch shut, check the keeper (the metal plate on the frame the latch clicks into). Loosen its two fixing screws, shift its position by a few millimetres in the direction the latch needs to reach, then retighten. Clean off any old wax, paint or grime blocking the latch mechanism itself with a dry cloth.

1 pack · Replacement screws (pack)

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PD-08Test and tidy upOpen and close the door fully several times to check it runs smoothly along its whole length and latches without forcing. Wipe down the track, frame and glass with a clean, damp cloth to remove any lubricant overspray. Put your tools away and bin any debris you removed from the track.

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