Fitting a Cat Flap Installing a cat flap your home is a fantastic option for any pet owner. No matter if your cat is older and requires extra security, or you have new kittens who require a vet check, there are plenty of options out there for you.

Installing a cat flap can be daunting for non-professionals but with the right instructions, it's not hard to do. The most important thing is planning, preparation and accuracy.

Choose the Right Door or Windows

There are a variety of cat flaps that are available, some with locks (which can be used to prevent your pet going out or coming in) and others with advanced features such as microchips for door entry systems. It is important to think about the ease of your cat to train to use the flap prior to making a buy and install one.

Based on the style of your home, it's generally best to put the cat flap near an opening or window that opens to an area that is protected from the garden so that your cat will feel secure entering and leaving the home. If possible, this will also give them a way back case they are chased by a cat or by a human intent on harming them.

You can install an egress flap inside the form of a uPVC door or a glass window however, it's not as simple as fitting one into the door made of wood. It's because uPVC or composite doors come in various thicknesses. This can impact the way holes are cut, and the type of door you can fix into.

If you're installing the flap in the glass of a door it is recommended to find a glazier who is experienced in this type of work to avoid any costly mistakes. If you're fitting the flap in a wooden door, start by introduction of your cat to it prior to fitting it to allow them to get used to its shape and size and explore it from every angle.

Find out the size of your cat's belly

In order to put in an appropriate cat flap that is a good fit for your pet, you'll have to measure your cat's height. This will help you ensure that the flap is the right height for your door or window, and that it's wide enough to allow them to enter and out easily.

To do this, lay your pet on their back and run your fingers gently along their belly. Check for any fat pads that are squishy that may be visible around their lower back, face and limbs. The extra padding offers your pet safety and allows them to move more easily, especially when performing the many acrobatics felines are famous for.

Alternatively, you can also use your pet's weight to determine the size of the opening you need. If your cat weighs at or above 5kg in weight for instance that's a 14x12cm cat flap opening is recommended.

Measure your windows or doors

This type of cat flap, as the name suggests, is designed to be affixed to the door. It allows your pet to enter and exit at its convenience. The flaps are made of aluminum or plastic and are located in the middle of the door. They feature a two-way swinging opening that can be opened by lightly pushing on either side. There are locking versions of these flaps that offer extra security, so your cat won't be able to simply traverse through the door from outside.


Cat flaps are also frequently employed in windows. They are able to be easily installed, but they need to be installed at a height where cats and dogs find it difficult to access them. If the window is too high to be used as a cat flap, then steps, ramps or purpose constructed stairs can be used to assist the animal get access to it.

A cat flap could also be fitted to a brick wall, but it is not recommended unless you are experienced in masonry work as it could weaken the structure of the wall. Before you begin, it's important to ensure that the wall is free of pipes and cables. It is recommended to consult an expert if you have to create a hole for cables and pipes. Wearing safety goggles or a dust mask can help you avoid inhaling the sawdust created when cutting into your walls.

Choose the right cat flap

There are a variety of cat flaps available and they all have different features. Some come with security options such as magnetic locks or microchip recognition to block entry by unauthorized persons and stop your pet allowing friends or other animals into the home. Some seals are weatherproof and insulation to keep out the elements and keep out drafts.

There are different sizes to choose from based on the breed and size of your pet. Cat flaps can be found in rectangular shapes, while others are square or circular. Selecting the best cat flap is determined by the space you have available as well as the type of door or window you intend to install it on.

Last but not least, take into consideration the kind of opening mechanism your cat flap will utilize. A simple aluminum or plastic swing-out door is a good alternative and is usually the cheapest. It won't prevent other animals and cats from entering, and you could also let in draughts.

Once you have selected the appropriate cat flap and measured the window or door and window, it's now time to put it in place it. Mark the belly height of the door using a ruler. Use a spirit level to make sure that the line is straight on the door and not too low. Create a template for the shape of the cat flap using your spirit level as a guide. Then, using a jigsaw, cut out the outline of the door. Once you are happy with the result then sand the edges and drill through the pencil marks to make holes for screws.

Make the Tools

Like any DIY tasks, it's best to have the proper tools to complete the task. The most essential things you'll need are the cat flap as well as a tape measure, a decent pencil, a spirit level, drill, file, and an jigsaw (depending on the door or window type).

Check with the manufacturer prior to making any changes to a door made of composite. This could invalidate the warranty or cause the weathertight seal to be broken. In this case, you'll probably have to install a new pane of toughened glass instead.

You'll need the jigsaw to cut your cat flap on wooden or uPVC door. Follow the instructions given by the manufacturer. Make use of a template to mark the size hole you need.

After you've cut the required hole, you'll need to smooth the edges of the opening to smooth them. This will stop future rust and water damage. You should also cover the holes in your window or door and the back of the flap to prevent wind and rain. When the sealant has dried and dry, you can install your new cat flap!

Install the Flap

If you want your cat to come and go as it pleases, fitting flaps can be helpful. It's a simple procedure that most people can accomplish on their own, but you may need to hire an expert for installing the flap on the form of a glass door or another type of uPVC door.

Begin by reading the instructions included with the flap to locate the template. This will provide you with an idea of where the holes for the flap will need to be drilled in the door. Mark the areas you'll have to drill with a pencil.

After you have marked the area on your door, use the jigsaw to cut the the cat flap. It is a relatively simple job, but you'll have to be comfortable using the saw. Numerous companies will perform this for you for a reasonable price If you're not sure how to tackle it yourself.

Then, you can screw the inside part of the door to the hole in your door. It is possible to seal the flap before you do this, in order to ensure it is waterproof and weatherproof. The outside of your cat flap may be placed on top of the bolts, and then securing them. You should test the cat flap on your cat to make sure that it's working properly and that it allows them to enter and exit easily.