Fitting a Cat Flap

· 6 min read
Fitting a Cat Flap

Getting a cat flap fitted into your home could be a huge step for any pet owner. There are many options available for you, no matter if your cat is getting older and requires extra security or if you have kittens that need to be examined.

It can be difficult for those who aren't professionals to put in the cat flap, but with right instructions it's easy. Planning, preparation and precision are the keys.

Select the Right Door or Windows

There are many different types of cat flaps, including some with locks that can be used to stop your pet from getting out or in and others with advanced features like microchips for door entry systems. It's important to think about how easy it will be to teach your cat to use the flap, before you buy and install one.

It is recommended to put the cat flap, based on the design of your home, inside the form of a window that opens to a sheltered garden area. This will help your cat feel safe when entering or leaving your home. This will also enable them to return inside if they're pursued by a pet or human who wants to harm them.

It is possible to install a cat flap in the form of a uPVC door or a glass window, but it's not as straightforward as fitting one into the door made of wood. This is because uPVC or composite doors come in a variety of thicknesses. This can impact the method of cutting holes, and the material you put into.

To avoid costly mistakes to avoid costly mistakes, it is recommended that you consult an expert glazier before installing the flap on a glass-fronted door. If you're installing the flap on an old wooden door, begin by the cat with it before you fit it so that they can become familiar with its size and shape and explore it from every angle.

Find out the size of your cat's belly

In order to install an appropriate cat flap that is the right size for your pet, you'll have to measure your cat. This will ensure that the flap is the correct height on your window or door and that it's big enough for them to enter and exit easily.

To do this, lay your pet on their back and gently rub your fingers across their belly. Look for squishy fat pad around the lower back, face or legs. The extra padding protects your pet and allows it to move more freely, particularly when performing feline Acrobatics.

Alternatively, you can also consider your pet's weight as a way to determine the size of an opening you need. If your cat weighs at or above 5kg in weight for instance an opening of 14 x 12cm flap for your cat is recommended.

Take a measurement of your door or window

This type of cat flap, as the name suggests is designed to be installed into the door. It lets your pet move in and out at their convenience. They are typically made of plastic or aluminium and simply are placed in the middle of the door. They come with a two-way swinging door that is opened by pressing lightly on either side. These flaps are available in locking versions which provide extra security which means that your cat can't traverse the door from outside.

A window is a common location for a cat's flap and these are easy enough to install, though they usually need to be located high enough as it's difficult for cats and dogs to access them. If the window is not sufficient in height to be used as a cat's flap, then you can opt for ramps, steps or specially designed stairs to help the animal reach it.

A cat flap could be incorporated into a brick wall but this is not recommended unless familiar with masonry work since it could weaken the structure of the wall. It's important to check that there aren't any cables and pipes within the wall before you begin. If they are, there must be a hole made for them. This is something you should always seek expert advice on. Wearing safety goggles or a dust mask can help you avoid inhaling the sawdust that is created when cutting through your walls.

Select  Continued  that is Right for You.

There are a variety of cat flaps on the market, and they come with different features. Some have security options like magnetic locks or microchips that block entry by unauthorized persons and prevent your pet from allowing guests or other animals to enter the house. Some also have insulation and weatherproof seals to block draughts and moisture.

There's also a range of sizes depending on the size and breed of your pet. Some cat flaps are rectangular whereas others are circular or square. Selecting the best cat flap will be determined by the space you have available and the kind of door or window you intend to install it on.

Finally consider the mechanism to open your cat flap is likely to have. The cheapest option is to use a simple swing-out aluminium or plastic door. But, it will not stop other pets or cats from gaining access and you could be letting draughts in as well.

It's time to install your cat flap. Start by marking the height of the belly on the door with a ruler. Use a spirit level to make sure that the line is sitting straight on the door and not too low. Create a template for the shape of the cat flap using your spirit level as a reference. Then, you can use your jigsaw to cut out the outline of the door. When you're satisfied with the results sand down the edges and then drill through the pencil lines to create holes for the screws.

Make the Tools

As with any DIY jobs, it's always best to have the right tools to complete the task. You'll need a cat flap as well as a pencil and tape measure as well as a spirit-level, drill and a jigsaw depending on the kind of window or door.

If you're installing a composite door, it is recommended to consult with the manufacturer prior to making any changes as this may cause the warranty to be invalidated or break the weathertight seal. In this instance it's likely that you'll have to replace the glass with a fresh piece of toughened glass.

You'll need an jigsaw for cutting out your cat flap on a wooden or uPVC door. Follow the directions given by the manufacturer. If possible, you can use a template to help you mark out the size of hole you'll will need to cut.


After you've made the hole, you must sand down the edges of the opening to smooth them. This will prevent any water damage or rust from happening in the future. Finally, you should apply any sealant that is needed 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. When the sealant has dried then you're now ready to put in your new cat flap!

Install the Flap

The installation of a flap will allow your cat to come and go whenever it wishes. This is a simple process that most people can accomplish on their own, but you may need to hire an expert if you're installing the flap on a glass door or other kind of uPVC door.

Start by looking at the instructions included with your cat flap to find the drawing template. This will provide you with an idea of where holes for the flap need to be made in the door. Then, mark the areas that you'll must drill using pencil.

After you've marked the area on your door, you can use the jigsaw to cut the the cat flap. This is a fairly simple job, but you'll need to be comfortable with the jigsaw. If you're worried about doing this yourself, there are a lot of businesses that can handle this for you at a very low cost.

Next, you will need to attach the inside of the flap onto the hole in your door. You may have to apply sealant prior to doing this to ensure it is weather and water resistant. The outer part of your cat flap may be placed on the bolts on top, and then securing them. You should test the cat flap on your cat to make sure that it is working correctly and that it allows them to exit and enter easily.