Fitting a Cat Flap

· 6 min read
Fitting a Cat Flap

Installing a cat-friendly flap in your home is a great option for any pet owner. There are a variety of options to you, regardless of whether your cat is older and requires additional security, or you have kittens who need to be examined.

Installing a cat flap could be intimidating for people who aren't professionals, but with the right instructions, it's easy to complete. The most important thing is planning, preparation and precision.

Choose the Right Door, or Window

There's a wide selection of cat flaps to choose from including some with locks (which can be used to prevent your pet from leaving or entering) and others that have high-tech features like microchip door entry systems.  cat flap installers  is important to consider how it is easy to teach your cat how to use the flap, before you buy and install one.

Depending on the design of your home, it's usually best to put the cat flap near a window or door that opens out into an area that is protected from the garden so that your cat is secure when going into and out of the house. If you can it will also provide them a route back in should they get pursued by a different cat or by humans who are intent on harming them.

It is possible to install a cat-flap inside a uPVC or composite door, but it's not as easy as putting one in a wood door. This is due to the fact that uPVC and composite doors come in different thicknesses, which can affect the way holes are cut and the materials you're fixing them into.

If you're installing the flap in the glass of a door it is recommended that you find a glazier who is experienced in this kind of work to avoid costly errors. If you're installing the flap into a wooden door it is recommended that you introduce your cat to it first so that it can become familiar with its size and shape.

Find out the size of your cat's belly

To install the right cat flap that's the right size for your pet, you'll have to measure your cat's size. This will ensure that the flap is at the right height on your door or window and that it's wide enough to allow them to enter and out easily.

To do this, place your pet on their back and gently rub your fingers across their belly. Look for any squishy fat pads that might be visible around their lower back, face or the limbs. The extra padding protects your pet and allows it to move more freely, especially when performing feline circus skills.


You can also use the weight of your pet to determine how large an opening you require. If your cat weighs up to 5Kg in weight, for example that's a 14x12cm flap for your cat is recommended.

Take a measurement of your door or window

As the name suggests, this type of cat flap is designed to be affixed to an opening and provide the pet with a way to leave or enter at any time it wishes. These flaps are constructed of plastic or aluminum and sit in the middle of the door. They feature a two-way swinging opening that opens by lightly pushing on either side. There are now locking versions of these flaps that offer extra security, so your cat can't simply walk through from the outside.

A window is another popular location for a cat flap, and they are simple enough to install, though they are usually located high enough as it's difficult for cats and dogs to reach them otherwise. If the window isn't sufficient to accommodate a cat's flap, then you can make use of ramps, steps or specially designed stairs to aid the animal in getting to it.

It is possible to insert an egress into the brick wall, however it is not recommended for those who aren't experienced in the masonry industry. This could weaken the wall's structure. It is important to make sure there aren't any cables and pipes within the wall before you start. If they are, a hole needs to be made for them. This is something you should always seek professional advice on. Wearing protective goggles or a dust mask will allow you to avoid breathing in the sawdust created when you cut into your walls.

Choose the right cat flap

There are many different cat flaps on the market and they all have different features. Some come with security options like magnetic locks or microchip recognition that stop unauthorized entry and prevent your pet from allowing friends or other animals into the house. Some seals are weatherproof and insulation to keep out the elements and keep out drafts.

There is also a choice of sizes, based on the size and breed of your pet. Some cat flaps come in rectangular shapes, while others are square or circular. The type of cat flap you pick will depend on the size of the opening and the kind of door or window you're installing it to.

Last but not least, think about the opening mechanism your cat flap will use. The most affordable option is a simple swing-out aluminium or plastic door. But, it will not prevent other cats or pets from gaining access and you could let draughts through too.

It's time to put in your cat flap. Make a mark on the belly of the door using your ruler. Make use of a spirit-level to ensure that the line is not too low and is in line with the door. Use your spirit level to draw a template of the cat flap. Then, using a saw, cut out the outline of the door. When you're happy with the result, sand the edges and drill through the pencil lines to create holes for the screws.

Make the Tools

It's essential to have the right tools when performing any DIY project. You'll need a cat flap along with a pencil and tape measure 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 case, it's likely that you'll have to replace the glass with a new piece of toughened glass.

You'll need to use a jigsaw to cut out your cat flap from a wooden or uPVC door. Follow the directions that are provided by the manufacturer. Make use of a template to determine the size of hole you need.

After you've cut the hole, you will need to sand the edges of the opening. This will prevent the possibility of water damage and rust. In the end, you must apply any necessary sealant to the rear of the cat flap as well as to the holes in the window or door to keep out the elements of wind and rain. Once the sealant has dried then you can put up your new cat-flap!

Install the Flap

Fitting a flap will allow your cat to go and come whenever it pleases. This is a straightforward process that most people can do on their own, but you may require the assistance of an expert if you're installing the flap on the form of a glass door or another kind of uPVC door.

Take a look at the instructions that came with your cat flap. There is an illustration of the template. This will give you an idea of where holes for the flap will need to be made in the door. Mark the areas where you have to drill using a pencil.

After you have mapped out the door's opening then use a jigsaw cut out the shape of the cat flap. This is a fairly simple task however you'll need be comfortable with the Jigsaw. If you're worried about doing this yourself, there are many businesses that can handle this for you at a very low cost.

The next step is to screw the inner part of the flap onto the door's hole. It may be necessary to seal the flap prior to you do this in order to keep it weatherproof and watertight. The outer part of your cat flap could be placed on the bolts' tops and then tightened together. You should test the cat flap on your cat to make sure that it functions properly and that it allows them to exit and enter easily.