Domakihub How to Fit a Cat Flap in a Panel Door
Cut the hole cleanly, seal it properly, and give your cat the run of the house — without wrecking the door.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Fitting a cat flap into a timber panel door is a satisfying afternoon job that most homeowners and property managers can handle with basic tools. The video above walks through the core technique visually; the steps below add the detail you need to do it cleanly — right dimensions, right position, no draughts — whether the door is in a Greek villa, a holiday rental, or a city apartment. One honest caveat: if your door is a fire-rated or structural element, check local building regulations before cutting into it.
Choosing the Right Cat Flap for a Panel Door
Panel doors — the kind with two or four recessed timber panels in a solid or engineered frame — are the ideal candidate for a cat flap. The thinner recessed panel section (typically 9–18 mm on a hollow-core interior door, or up to 45 mm on a solid exterior door) is easier and safer to cut than the stile or rail. Always measure the panel thickness before buying the flap; most standard cat flaps cover doors from 16 mm up to 60 mm, and microchip models often come with tunnel extensions for thicker doors.
Choose a flap size based on your cat: the opening should be roughly 15 cm wide by 15 cm tall for an average adult cat. Microchip-activated flaps are strongly recommended for any external door in Greece, where feral cats are numerous. For doors exposed to sea air — common in coastal holiday rentals — look for a corrosion-resistant frame (aluminium or quality ABS plastic) to prevent the hinge from seizing.
What to Check Before You Cut
Locate the panel you plan to cut into and tap across it — a hollow tap means a hollow-core board (chipboard or cardboard honeycomb fill), while a solid thud indicates MDF or timber. A solid panel is easier to cut neatly and holds the fixing screws more firmly. If the door is hollow-core, you may need to fit a timber-infill frame into the hole to give the screws something to grip, or use the bolt-through method provided with most flaps.
Position matters more than most guides admit. Centre the flap horizontally in the panel and set the bottom of the opening 15 cm above floor level — low enough for a cat to step through comfortably, not so low that it scrapes the frame on an uneven tiled floor. On external doors, also check that there is no obstruction on the outside: steps, a threshold strip, or a door mat can all block the flap from swinging open.
How to Fit a Cat Flap in a Panel Door: Step by Step
- 1
Mark the cutting template
Use the paper or cardboard template supplied with the flap (or trace the inner frame directly). Tape it to the door panel at the correct height, check it is level with a spirit level or a phone level app, and trace the cut-line with a pencil. Double-check the dimensions against the flap body — you want a snug fit with no more than 2–3 mm of clearance all around.
- 2
Drill pilot holes at the corners
Fit a 10–12 mm spade or paddle bit and drill a hole at each corner of the marked rectangle, staying just inside the line. These corner holes let you turn the jigsaw blade without tearing the timber and give you a clean start on each straight cut. Clamp a piece of scrap timber to the far side of the door to prevent blow-out as the bit exits.
- 3
Cut out the panel with a jigsaw
Fit a fine-tooth wood blade (14–18 TPI) and cut from hole to hole along each marked line. Keep the jigsaw base plate flat against the door surface and move at a steady, moderate speed — rushing causes the blade to wander. Support the cut-out piece from inside with your free hand so it does not drop and splinter the panel edge as the last cut is made.
- 4
Clean the edges and test-fit the flap
File or sand the cut edges smooth and remove any loose timber fibres. If the door is hollow-core with a cardboard fill, cut back the cardboard 20 mm from the edge on all sides, then fill the void with strips of 18 mm timber pinned and glued flush with the face — this creates a solid perimeter for the screws. Offer up the outer and inner frames of the flap and check the fit before committing.
- 5
Fit, seal, and secure the flap
Push the tunnel body through the hole from the outside. Apply a thin bead of neutral-cure silicone sealant around the outer frame flange before pressing it against the door face — this weatherproofs the joint on external doors and prevents draughts on internal ones. Fit the inner frame from the other side, thread the fixing bolts through, and tighten evenly in a cross pattern. Wipe away any excess silicone before it cures. Test the flap swings freely, then introduce your cat gradually — a prop-open position for the first few days helps them discover it on their own terms.
Rather have a pro handle it?
Get a vetted renovation pro in your city — one number, booked in EN/EL/DE.
FAQ
- Can I fit a cat flap in a hollow-core interior panel door?
- Yes, but hollow-core doors need extra preparation. After cutting the hole, you will find a cardboard or paper honeycomb fill. Remove it back 20 mm from the cut edge on all sides and glue in solid timber infill strips flush with the face. This gives the fixing bolts solid material to grip and prevents the face veneer from cracking over time. Without this step the screws will eventually pull through.
- Does fitting a cat flap in an external door void the door warranty or breach a tenancy agreement?
- In Greece, standard residential tenancy law (Law 1703/1987 and general civil code provisions) requires tenants to restore the property to its original condition at the end of the lease. Cutting into a door is a permanent modification, so written landlord consent is advisable before proceeding. For holiday rental properties managed on platforms like Airbnb, fitting a permanent flap is the owner's decision; a removable snap-in insert is a lower-risk interim solution where the flap is likely to be used seasonally.
- My door panel is only 9 mm thick — is that enough for a cat flap?
- Most standard cat flaps specify a minimum door thickness of 16 mm, and a 9 mm panel is below that. In practice the flap will still sit physically in the hole, but the fixing bolts may be too long to tighten flush and the tunnel tunnel will protrude. The cleaner solution is to use a flap that allows for very thin panels, or to recess a 10 mm timber backing plate around the opening on one face so the combined thickness meets the minimum — then finish the exposed timber edge with a matching iron-on veneer tape.