Domakihub How to Install a Cat Flap: Step-by-Step Guide for Any Door
Cut, fit, and seal a cat flap in a wooden or uPVC door in under an hour — no specialist tools required.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
A cat flap gives your pet the freedom to come and go without scratching at the door at midnight — a welcome upgrade in any home, holiday rental, or hotel suite that welcomes guests with animals. The video above shows a clean real-world installation on a wooden door in under twenty minutes; the steps below cover the full process including material choices and the sealing that matters most in Greece's variable climate. Whether you own a villa in Crete or an apartment in Athens, this guide will walk you through every cut.
Choosing the Right Cat Flap for Your Door
Cat flaps come in four main types: basic manual flaps, magnetic-collar models, infrared-collar models, and microchip-activated flaps. For a private home or long-term rental a microchip flap is worth the extra cost — it reads your cat's existing implanted chip, so no collar is needed and no stray animal can wander in. For a holiday rental where different guests bring different pets, a simple manual or magnetic flap keeps maintenance minimal.
Door material matters too. Wooden and uPVC doors are the easiest to cut; a standard jigsaw handles both. Glass doors and cavity walls require specialist tunnel extensions and, for glass, a professional glazier. Always check the door thickness and compare it against the tunnel depth listed on the flap's packaging before you buy.
Tools and Materials You Will Need
Gather everything before you start: the cat flap kit (flap, frame, tunnel, fixings), a tape measure, pencil, masking tape, a drill with a suitable bit, a jigsaw or hole saw, sandpaper, and weatherproof sealant. A second pair of hands is useful when holding the template in place.
For uPVC doors pick jigsaw blades rated for plastic to avoid cracking the material. For wooden doors a medium-tooth wood blade works well. Always have a damp cloth ready to wipe away dust before applying sealant — adhesion fails on dusty surfaces, and a poor seal lets in cold draughts or rain.
Installation Steps
- 1
Mark and position the opening
Hold the paper template (usually included in the box) against the door at the correct height — the flap's bottom edge should sit roughly 5 cm above the floor so your cat steps through comfortably rather than jumping. Secure the template with masking tape, then use a pencil to trace the cutting outline. Double-check the position from both sides of the door before drilling anything.
- 2
Drill pilot holes at the corners
Drill a hole at each corner of the marked rectangle, just inside the pencil line. These pilot holes give the jigsaw blade a clean starting point and prevent the material from cracking or splitting as you begin the cut. Use a drill bit slightly wider than the jigsaw blade's width. On uPVC doors apply steady, slow pressure to avoid melting the plastic.
- 3
Cut out the opening
Insert the jigsaw blade into one of the pilot holes and cut along the pencil line, moving from corner to corner in smooth, continuous strokes. Support the cut-out piece from the other side if you can — letting it drop suddenly can splinter a wooden door. Once the piece is out, smooth all edges with sandpaper until they are clean and even.
- 4
Fit the tunnel and frames
Slide the tunnel through the opening so it spans the full door thickness. Push the outer frame and inner frame onto each end of the tunnel from their respective sides and press them firmly against the door surface. Insert the fixing screws through the inner frame, through the door, and into the outer frame — tighten them evenly in a cross pattern so the frames sit flush without warping.
- 5
Seal the edges and test the flap
Run a thin bead of weatherproof, paintable sealant around the join between each frame and the door on both sides. Smooth it with a wet finger and leave it to cure for the time stated on the tube — usually two to four hours. Once cured, press the flap open a few times to confirm it swings freely and springs back. Then coax your cat through with a treat, holding the flap open the first few times until they learn to push it themselves.
Rather have a pro handle it?
Get a vetted handyman pro in your city — one number, booked in EN/EL/DE.
FAQ
- Can I install a cat flap in a rented apartment in Greece without losing my deposit?
- In most Greek tenancy agreements structural modifications require landlord consent in writing. A cat flap does leave a permanent hole, so always get approval before cutting. Some tenants use removable panel inserts that fit inside an existing glass pane — a glazier cuts a small pane to size and the flap sits in that, leaving the original door intact.
- My door is a uPVC double-glazed unit — can I still fit a cat flap myself?
- Not without specialist help. Cutting into a sealed double-glazed unit destroys the argon-gas seal, causing condensation and heat loss. You need a glazier to replace one pane with a single pane that already has the cat flap fitted, or to install a purpose-made replacement panel. For solid uPVC doors (without glass) a standard jigsaw with a plastic blade is fine.
- What size cat flap do I need?
- Measure your cat at its widest point — usually the shoulders or hips — and add about 4 cm on each side for comfort. Most adult cats fit a standard flap opening of roughly 15 cm wide by 17 cm tall. Large breeds like Maine Coons need a 'large' or 'dog-medium' flap. When in doubt, size up — a slightly oversized flap is easier for the cat and costs very little extra.