Fitting a Cat Flap

· 6 min read
Fitting a Cat Flap

Installing a cat-friendly flap in your home is a fantastic step for any pet owner. If your cat is old and requires extra security, or you have kittens that need to be vetted there are plenty of options out there for you.

It can be a bit daunting for people who aren't experts in installing an animal flap, but with the proper instructions, it's simple. The crucial factor is preparation, planning and precision.

Choose the Right Door or Window

There are a variety of cat flaps to choose from, some with locks (which can be used to prevent your pet from going out or entering) and others with high-tech features such as microchip door entry systems. It is important to consider how it is easy to teach your cat how to use the flap, before you purchase and install one.

Based on the style of your home, it's generally best to place the cat flap inside a window or door that opens onto an area of protection in the garden so your cat will feel secure leaving and entering the home. If possible it will also provide them a route back in should they get pursued by a different cat or by a human intent to harm them.

It is possible to install a cat flap in the case of a uPVC door or a glass window, but it's not as simple as putting one in wooden doors. It's because uPVC or composite doors are available in a variety of thicknesses. This can affect the how holes are cut and the type of door you can fix into.

If you're installing the flap inside the glass of a door it is recommended to consult a glazier who specialises in this type of work to avoid costly mistakes. If you are fitting the flap into an existing wooden door it is recommended that you introduce your cat to it first so that it can become familiar with its dimensions and shape.

Take a look at your cat's belly measurement

You'll need your cat's measurements to ensure that the cat flap you put in is a perfect fit. This will help you make sure that the flap is placed at the right height for the door or window, and that it's big enough for him to enter and leave easily.

To do this, place your pet on their back and gently run your fingers across their belly. Look for a fat pad that is squishy around the lower back and face, as well as the limbs. The extra padding protects 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 require. If your cat weighs more than 5Kg, for example the suggested flap size is 14x12cm.

Make sure you measure your door or window

This kind of cat flap, as its name suggests, is designed to be installed into the door. It allows your pet to move in and out at their convenience. They are typically made of plastic or aluminium and simply rest in the middle of the door. They have an open door that is opened by pushing lightly on either side. They are available in locking versions that offer added security, so your cat cannot simply walk through the door from outside.

Cat flaps are also commonly used on windows. They are able to be easily installed, but they need to be placed at an elevated level since cats and dogs find it difficult to reach them. If the window is too high for a cat flap, ramps, steps, or specially built stairs can be utilized to help the animal access it.

A cat flap can also be fitted into a brick wall, however this is not recommended unless you're skilled in masonry work as it could weaken the structure of the wall. Before you begin, it is important to make sure that the wall is free of cables and pipes. If there are, then an opening must be made for them. This is something you should always seek expert advice on. Wearing protective goggles or a dust mask will help you avoid inhaling the sawdust that is created when you cut into your walls.

Choose the right cat flap

There are numerous cat flaps that are available on the market, and they come with various features. Some are equipped with security features like magnetic locks or microchips that block entry by unauthorized persons and restrict your pet from letting pets or friends into the home.  repairmywindowsanddoors  have insulation and weatherproof seals to keep out water and drafts.

There's also a variety of sizes based on the size and breed of your pet. Cat flaps can be found in rectangular shapes, whereas others are circular or square. The type of cat flap you select will depend on the size of the opening and the kind of door or window you're fitting it to.

Finally, think about the mechanism for opening your cat flap will have. The most affordable option is a simple swing-out aluminium or plastic door. It will not stop other animals and cats from entering the room, and you could be letting in drafts.

It's time to put in your cat flap. Determine the belly height of the door with your ruler. Use a spirit-level to make sure that the line isn't too low and is straight on the door. Draw a template of the shape of the cat flap using your spirit level as a reference. Then, use a Jigsaw to cut the door's outline. When you're satisfied with the results sand down the edges and then drill through the pencil marks to create holes for the screws.

Make sure you have the tools ready

Like any DIY tasks, it's advisable to make sure you have the appropriate tools for the job. The most important things you'll require are the cat flap itself as well as a tape measure, an excellent pencil and a spirit level a file, drill and a jigsaw (depending on your windows or doors).

If you're installing in a composite door, it is recommended to check with the manufacturer prior to making any changes since this could invalidate the warranty or break the weathertight seal. In this scenario, you'll probably require a new pane of toughened glass instead.

You'll require a jigsaw to cut out your cat flap on wooden or uPVC door. Follow the instructions that are provided by the manufacturer. If you can, use a template to help you mark out the dimensions of the hole you have to cut.

After you've cut the hole, you'll have to sand the edges of the opening. This will help prevent any future water damage or rust. It is also recommended to seal the holes in your window or door and the side of the flap to block rain and wind. When the sealant has dried, you're ready to install your new cat flap!

Install the Flap

The installation of 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 for installing the flap on a glass door or other type of uPVC door.


Check out the directions included with the cat flap. You will find a template drawing. This will provide you with an idea of where the holes for the flap have to be drilled into the door. Mark the areas in which you will have to drill using pencil.

After you've marked the area on your door, you can use the jigsaw to cut the design for the cat flap. This is a fairly simple task however you'll need be comfortable using a Jigsaw. Many companies will complete this work for you at a reasonable cost in case you're hesitant to take on the task yourself.

Then, attach the outer part to the hole in your door. It is possible to seal the flap prior to you do this, in order to ensure it is waterproof and weatherproof. You can then put the outer portion of the flap on the top of the fixing bolts and tighten them all together. You should test the cat flap on your cat to make sure that it is working correctly and allows them to enter and exit easily.