Fitting a Cat Flap

· 6 min read
Fitting a Cat Flap

Getting a cat flap fitted inside your home can be a major step for any pet owner. There are a variety of options for you, no matter if your cat is old and needs extra security, or you have kittens who need to be vetted.


It can be a bit daunting for non-professionals to install the cat flap, but with the proper instructions, it's simple. The crucial factor is preparation, planning and accuracy.

Choose the Right Door, or Window

There are a myriad of kinds of cat flaps, including some with locks that can be used to prevent your pet from going out or in and others with advanced features like microchips for door entry systems. It is important to consider how easy it will be to train your cat to use the flap before you buy and install one.

It's best to place the cat flap, depending on the style of your house, in an opening that leads into an area of the garden that is protected. This will help your cat feel safe when entering or leaving your home. This will also allow them to return inside if they are chased by another animal or humans who want to harm them.

It is possible to install a cat flap in the form of a uPVC door or glass window, but it's not as straightforward as putting one in wooden doors. This is because uPVC and composite doors come in different thicknesses, which affect the way holes are cut and the materials you're fixing them into.

If you're installing the flap inside the glass of a door it is recommended to consult a glazier who specialises in this kind of work to avoid costly errors. If you're installing the flap to the door made of wood, start by the cat with it before you fit it to allow them to get used to its shape and size and explore it from every angle.

Take a look at your cat's belly measurement

In order to install the right cat flap that's the right size for your cat, you'll need to measure your cat. This will help you ensure that your cat flap is placed at the correct height on the door or window, and also that it's large enough to allow him to enter and leave easily.

To do this, lay your pet on their back and run your fingers gently along their belly. Look for any squishy fat pads that could be visible on their lower back, face, and legs. The extra padding shields your pet and allows it to move more freely, especially when performing feline acrobatics.

You can also consider the weight of your pet to determine how large an opening you need. If your cat weighs up to 5Kg, for example, the suggested cat flap opening size is 14 x 12cm.

Make sure you measure your door or window

This type of cat flap, as the name suggests, is made to be fitted into a door. It lets your pet be able to enter and exit at his/her convenience. They are usually made of aluminum or plastic and rest in the middle of the door. They have a two-way swinging door that is opened by pressing lightly on either side. They are available with locking options that provide additional security so that your cat is not able to enter the door from outside.

A window is a common location for a cat flap and these are easy enough to fit, although they are usually set up high as it is difficult for cats and dogs to reach them otherwise. If  cat flap installation  is not sufficient in height to be used as a cat's flap, you can opt for ramps, steps, or stairs that are specially designed to assist the animal in reaching it.

It is possible to install an egress into a brickwall, but it is not recommended for those who aren't familiar with masonry. This could weaken the structure of the wall. It's important to check that there aren't any cables and pipes inside the wall before you begin. If there are, a hole needs to be made for them. This is something you should always seek expert advice on. It is also recommended to wear safety goggles and a dust protection mask to avoid inhaling any of the sawdust created by cutting holes in the walls of your home.

Choose the right cat flap

There are many different cat flaps on the market and all of them offer different features. Some cat flaps have security features such as magnetic locks or microchip recognition that block entry by anyone who isn't authorized. They also keep your pet from letting guests or other animals into the home. Certain seals are weatherproof and have insulation to keep out moisture and draughts.

There's also a range of sizes depending on the size and breed of your pet. Certain cat flaps are available in rectangular shapes, whereas others are circular or square. The type of cat flap you choose will depend on the dimensions of the opening as well as the type of window or door you're fitting it to.

Last but not least, think about the opening mechanism the cat flap will employ. The cheapest option is to use a simple swing-out aluminium or plastic door. But, it will not prevent other cats or pets from entering and you may let draughts in as well.

It's time to install your cat flap. Start by marking the belly's height on the door with your ruler. Use a spirit level to ensure that the line is straight against the door and not too low. Utilize your spirit level to draw a sketch of the cat flap. Then, using the Jigsaw, cut the outline of the door. When you are satisfied with the result, sand the edges down and drill through the pencil marks to create holes for screws.

Make the Tools

It's essential to have the right tools when performing any DIY project. You'll require the cat flap along with tape measure and pencil along with a spirit-level, drill, and a jigsaw, depending on the kind of window or door.

Consult the manufacturer before making any changes to a door made of composite. This could invalidate the warranty or cause the weathertight seal to become damaged. In this instance, it's likely that you'll have to replace the glass with a new piece of toughened glass.

For wooden or uPVC doors, you'll need to cut out the shape of your cat flap using the Jigsaw. Follow the guidelines that are provided by the manufacturer. If possible, you can use an example to mark out the size of hole you'll need to cut.

After you've made the hole, you should then smooth the edges of the opening to smooth them. This will stop any rust or water damage from happening in the near future. Also, you should apply any sealant you require to the rear of the cat flap and to the holes in the window or door to keep out the elements of wind and rain. Once the sealant is dry, you're ready to install your new cat flap!

Install the Flap

Fitting a flap will allow your cat to move around whenever it wants. It's a simple procedure that most people can do themselves, although you may require the help of an expert if you're installing the flap on the form of a glass door or another type of uPVC door.

Take a look at the instructions included with the cat flap. You will find an illustration of the template. This will give you an idea of where the holes will be made for the flap on the door. Note the areas you'll have to drill with the pencil.

After you have marked the area on your door, use the jigsaw and cut out the shape for the cat flap. This is a relatively easy task, but you'll require a good understanding of a jigsaw. If you're worried about doing it yourself, there are many businesses that can handle this for you at a minimal cost.

Then, you can screw the inside part to the hole of your door. It might be necessary to seal the flap before you do this, in order to ensure it is weatherproof and watertight. The outside of your cat flap may be placed on top of the bolts, and then securing them. It is recommended that you test the flap using your cat to ensure that it functions properly and that they can move easily through it.