Fitting a Cat Flap

· 6 min read
Fitting a Cat Flap

Installing a cat flap inside your home can be a big step for any pet owner. There are many options available for you, no matter if your cat is getting older and requires additional security or if you have kittens that need to be checked.

Installing a cat flap may be intimidating for people who aren't professionals, but, with the right instructions, it's easy to accomplish. Planning, preparation and precision are the keys.

Select the Right Door or Windows

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 inside, and others that have modern features such as microchips or a door entry system. But, it's important to think about the ease of your cat to teach to use the flap before you purchase and fit one.

It's best to place the cat flap, depending on the style of your home, inside the form of a window that opens to a garden that is sheltered. This will help your cat feel secure when entering or leaving your home. This will also allow them to go back inside in the event of being chased by other animals or human who wants to hurt them.

It's possible to install a cat-flap in a uPVC or composite door, but it isn't the same as fitting one on a wooden door. It's because uPVC or composite doors are available in various thicknesses. This could affect the method of cutting holes, and what you fix into.

If you're installing the flap on the glass of a door, it's recommended that you find a glazier who is experienced in such work to avoid any costly errors. If you're fitting the flap to a wooden door you must introduce your cat first to ensure that it becomes familiar with its size and shape.

Find out the size of your cat's belly

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

To do this, put your pet on their back and gently rub your fingers across their belly. Look for a fat pad that is squishy around the lower back or face, or around the limbs. The padding helps protect your pet and allows it to move more freely, especially when performing feline acrobatics.

Alternately, you could consider your pet's weight as a way to gauge how big an opening you require. If your cat weighs up to 5Kg in weight for instance, a 14 x 12cm flap for the cat is advised.

Take a measurement of your door or window

This type of cat flap, as its name suggests is designed to be affixed to the door. It lets your pet enter and exit at its convenience. They are usually made from aluminum or plastic and sit in the centre of the door with an open door that is opened by pressing lightly on either side. The flaps are available with locking options that provide additional security so your cat cannot simply traverse the door from outside.

A window is a common location for a cat's 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 in height to be used as the flap for cats, you can make use of steps, ramps or specially designed stairs to assist the animal in reaching it.

A cat flap can be incorporated into a brick wall, however it is not recommended unless you're familiar with masonry work since it could weaken the wall's structure. It is important to make sure there are no cables and pipes in the wall prior to you begin. You should always consult a professional if you need to create a hole for cables and pipes. It is also recommended to wear safety goggles and a dust protection mask to prevent inhaling any sawdust generated by cutting holes in the walls of your house.

Select the Right Cat Flap

There are many different cat flaps on the market and they all have various features. Some come with security options such as magnetic locks or microchip recognition that stop unauthorized entry and restrict your pet from letting friends or other animals into the home. Some also have insulation and weatherproof seals to keep out water and drafts.

There are also different sizes to choose from based on the breed and size of your pet. Certain cat flaps are rectangular whereas others are circular or square. The type of cat flap you select will depend on the dimensions of the opening as well as the kind of door or window you're fitting it to.

The last thing to do is take into consideration the kind of opening mechanism your cat flap will utilize. A simple aluminum or plastic swing-out door is one choice and is typically the cheapest. It won't prevent other pets and cats from entering however, and you could let in draughts.

Once you've selected the correct cat flap and measured the door or window then it's time to install it. 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 against the door and not too low. Draw a template of the shape of the cat flap using your spirit level as a reference. Then, you can use your jigsaw to cut out the outline in the door. Once you are satisfied with the result, sand the edges down and drill through the pencil lines to create holes for screws.

Prepare the Tools

As with all DIY tasks, it's advisable to make sure you have the right tools for the job. You'll require the cat flap, an eraser and tape measure, a spirit-level, a drill, and a jigsaw, depending on the type of door or window.

Check with the manufacturer prior to making any modifications to a composite door. This could invalidate the warranty or cause the weathertight seal to be damaged. In this scenario you'll need to fit a new pane of toughened glass instead.

You'll require a jigsaw to cut out your cat flap on a wooden or uPVC door. Follow the instructions given by the manufacturer. Use a template if possible to determine the size of hole you need.


After you've cut the hole, you'll have to sand off the edges of the opening. This will stop any water damage or rust from happening in the near future. Also, you should apply any sealant you require to the back of the cat flap and to the holes in the door or window to keep out the elements of wind and rain. After the sealant has dried and dry, you can install your new cat flap!

Install the Flap

Installing a flap allows your cat to come and go whenever it wants. It's a simple procedure that most people can do by themselves, though you may need to hire a professional if you are installing the flap in an unglazed door or any other kind of uPVC door.

Begin by reading the instructions provided with your cat flap to locate the template.  cat flap cover for winter  will give you an idea of where holes for the flap need to be drilled into the door. Then, mark the places that you'll have to drill using a pencil.

After you have marked the area on your door, use the jigsaw to cut the the cat flap. This is a relatively simple job however, you'll need to be comfortable with a jigsaw. If you are concerned about doing this yourself, there are plenty of companies that can complete this for you at a very low cost.

Next, you will need to attach the inside of the flap onto the door's hole. You may have to apply sealant before doing this to ensure that it is weather and water resistant. The outer part of your cat flap could be placed on the bolts on top, and then tacked together. It is recommended that you test the cat flap with your cat to make sure that it works correctly and that they can enter and leave easily through it.