Cat Flap Stuck Open? 6 Causes and Quick Fixes

Almost every modern cat flap closes with a small magnetic strip in the bottom edge of the flap and a matching strip in the frame. Over time, especially in heavy-use households, the adhesive backing fails and the magnet slips out.

Fix: Check the bottom edge of the swinging flap and the corresponding spot on the frame. If a magnet is loose, you'll feel or see it. Glue it back with a small dab of contact adhesive (Gorilla Glue, Loctite Super Glue Gel — anything except hot glue, which fails in temperature swings).

Plastic cat flap doors that face direct south-facing sun can warp slightly, especially on hot summer days. Once warped, they won't sit flush in the frame.

Fix: In mild cases, a warm (not hot) hairdryer over the warped section while gently pressing it flat for 2 minutes can restore the shape. In severe cases the flap door is a cheap replacement part — typically £8–£20 direct from the manufacturer (SureFlap, PetSafe and Closer Pets all sell replacement flap doors).

Cat flap doors hang on small plastic hinge pins at the top. After thousands of cycles these can wear, snap or pop out.

Fix: Lift the flap and inspect both hinge pins. If one is broken, the flap will hang loose on one side and not close. Replacement hinge kits cost £3–£8 and take 5 minutes to fit.

Leaves, mud, cat hair or even kibble can wedge between the flap door and the frame seal, preventing full closure.

Fix: Open the flap fully and wipe both sides of the frame seal with a damp cloth. Vacuum out the channel. Check the rubber seal around the perimeter — if it's compressed flat or torn, a replacement is needed (cheap on Amazon or direct from the brand).

Manual 4-way lock cat flaps have a small slider on the inside face. If it's between settings or has dirt in the track, it can hold the flap part-open.

Fix: Move the slider firmly to each of the four positions, then back to 'fully unlocked'. Listen for a click. If sticky, a tiny drop of silicone spray on the slider track (never WD-40 — it attracts dust) will free it up.

If you've recently bought a replacement flap door online and it doesn't close properly, you may have ordered the wrong model. SureFlap Original, SureFlap Microchip and SureFlap Connect all use slightly different flap doors that look identical but aren't interchangeable.

Fix: Check the model number on the inside of your flap (small label near the battery compartment) and re-order. Returns are usually free.

If multiple issues stack up — warped flap, broken hinge, failing magnets, perished seals — it's often cheaper and quicker to replace the whole unit. A like-for-like swap into the existing aperture in your uPVC door, glass door or composite door takes us under an hour — and you get a fresh 3-year guarantee. Request a quote for your job.