Fitting a Cat Flap

Fitting a Cat Flap

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

Installing a cat flap can be daunting for non-professionals however, with the proper instructions, it's not hard to do. The crucial factor is preparation, planning and precision.

Select the Right Door or Window

There are a variety of cat flaps, some with locks that can be used to keep your pet from going out or in, while others have modern features such as microchips or a door entry systems. It is important to think about how it is easy to teach your cat to use the flap, before you buy and install one.

It is recommended to put the cat flap, depending on the style of your home, inside an opening that leads into a sheltered garden area. This will help your cat feel safe when entering or leaving your home. This will also enable them to go back inside if they are chased by another animal or human beings who wish to harm them.

You can install the cat flap on a uPVC door or glass window however, it's not as straightforward as fitting one into a wooden door. This is because uPVC and composite doors come in different thicknesses, and this can impact the way holes are cut and what you're fixing to.

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

Take a look at your cat's belly measurement

In order to install an appropriate cat flap that is suitable for your pet, you'll need to measure your cat's height. This will ensure that the flap is the right height for your door or window and that it's large enough for them to enter and out easily.

To do this, put your pet on their back and gently run your fingers across their belly. Look for squishy fat pad around the lower back, face or legs. The padding gives your pet protection and allows them to move more easily, especially when performing the acrobatics cats are known for.

You can also consider the weight of your pet to determine how large an opening you require. If your cat is up to 5Kg in weight, for example an opening of 14 x 12cm cat flap opening is advised.

Make sure you measure your windows or doors

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 enter or leave at any time it wishes. These flaps are constructed of plastic or aluminum and are placed in the middle of the door. They have a two-way swinging opening that opens by gently pushing on either side. There are locks on some of these flaps, which provide extra security, so your cat can't simply traverse through the door from outside.


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

It is possible to put the cat flap onto brick walls, however it is not recommended for people who aren't familiar with the masonry industry. This could weaken the wall's structure. Before you begin, it's important to ensure that the wall is free of cables and pipes. Always consult a professional if you need to create a hole for pipes and cables. It is also recommended to wear goggles with a protective lens and a dust protection mask to avoid inhaling any sawdust generated by cutting holes in your home's walls.

Choose the Cat Flap that is right for you.

There are numerous cat flaps that are available on the market, and come with various features.  cat flap fitters  have security options such as magnetic locks or microchip recognition to prevent unauthorized entry and also prevent your pet from allowing guests or other animals to enter the house. Some also have insulation and weatherproof seals that keep out draughts and moisture.

There are various sizes to choose from based on the size and breed of your pet. Cat flaps can be found in rectangular shapes, while others are circular or square. Selecting the best cat flap will be dictated by the space you have available and the kind of door or window you are fitting it to.

Lastly consider the opening mechanism that your cat flap is likely to have. A simple plastic or aluminium swing-out door is an choice and is typically the cheapest. It won't prevent other cats and pets from entering, and you could also be letting in draughts.

It's time to install your cat flap. Begin by marking the belly's height on the door with your ruler. Use a spirit-level to make sure the line is not too low and is in line with the door. Utilize your spirit level to draw a sketch of the flap for cats. Then, you can use your 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 make holes for screws.

Prepare the Tools

It's essential to have the right tools available when doing any DIY project. The most important things you'll require are the cat flap along with a tape measure, an excellent pencil, a spirit level, drill, file and the jigsaw (depending on the windows or doors).

Check with the manufacturer prior to making any changes to a composite door. This could invalidate the warranty, or cause the weathertight seal to become broken. In this instance you'll likely require an additional pane of toughened glass instead.

For wooden or uPVC doors you'll need to cut out the shape of your cat flap with the Jigsaw. Follow the guidelines provided by the manufacturer. Use a template to determine the size of hole you'll require.

After you've made the hole, you must smooth the edges of the opening to smooth them. This will help prevent future rust and water damage. It is also recommended to cover the holes in your door or window and the back of the flap to keep out rain and wind. After the sealant has dried then you're now ready to put in your new cat flap!

Install the Flap

If you want your cat to move around whenever it wants, installing flaps can be helpful. The majority of people can install the flap by themselves. However when you plan to put it in a glass or uPVC type door, you may require a professional.

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 will need to be drilled into the door. Mark the areas you'll need to drill into using pencil.

After you have marked the area on your door, use the jigsaw and cut out the design for the cat flap. It is a relatively simple task, but you'll require a good understanding of a Jigsaw. If you are concerned about doing it yourself, there are many companies that can complete this for you at a very low cost.

Then, attach the outer part to the hole in your door. You may have to apply sealant prior to doing this to ensure it remains weather-proof and water resistant. You can then place the outer part of the flap on top of the fixing bolts and then tighten them all. It is recommended to test the flap using your cat to make sure that it functions properly and that they are able to move easily through it.