Fitting a Cat Flap in a UPVC Door

· 6 min read
Fitting a Cat Flap in a UPVC Door

The freedom to let your cat move around the house whenever it wants is an excellent way to keep your pet active and mentally stimulated. A flap can help reduce the frequency of accidents due to toilets, making it easier for the cat to leave the home when necessary.

Take a measurement of the door

A cat flap lets your pet leave and come back whenever they want without you having to open the door. This is a great way to keep your pet in the house when you are away or at home. It also helps prevent unwanted pests from entering.

It is important to take measurements of the door to ensure you get the right size  cat flap . There are many sizes available. You should then make sure that the cat flap is the proper size for the door you have. Otherwise, it could be too large or small, and your cat could be unable to use it.

Take a ruler, and take measurements of the width at various places along the edges of the door. Also, determine the door's height in a couple of places. This is because the door that is too high can cause your cat to perform a gymnast's routine every time they use the flap!

If you're not sure how to measure the door, it may be best to ask for help from a glazier or someone who does this type of work frequently. They will be able determine if your door is suitable for cat flaps and give you advice on the right size flap to buy.

Mark out the shape of the hole on your door once you have your measurements. This will provide you with a guide when it comes to cutting the hole out and will help you avoid making mistakes that could cost you money in the end!

Make sure that you put holes in the right location. If you're installing an apex flap to the patio door, it is crucial that the hole does not get too close to the hinges. This could result in leakage or issues with the seal.

It is best to delegate the job of installing the cat flap on glass doors to an experienced glazier. It isn't easy to install a cat-flap in an existing pane. It is also possible that it cracks and loses its weatherproof seal.

Measure the Cat

A cat flap allows your pet to leave and come back whenever they want without you having to leave him home alone. It also helps stop the draughts from entering your home, which isn't bad for you or your cat!

However, if you own a uPVC or composite door, it could be a challenge to put in the cat flap. These doors are made of different materials and the installation is different. Before you consider fitting the cat flap on your uPVC or composite door, be sure that it's compatible, and you have checked with the manufacturers as alterations may cause the warranty to be invalidated.

Generally speaking, these types of doors are built to be tough and durable, with insulation built in. This makes them more resistant to weather elements than other types of doors, however they can be difficult to install a cat flap into. If you're not sure if your uPVC or composite door can accommodate the cat flap, make sure you consult with a professional jointer prior to starting.

To ensure that your cat is able to access the door, you'll need to determine their height. This is easiest if they are sleeping or calm, so that they aren't moving around too much. Once you know their height and weight, you can determine the distance from their stomach to the floor to determine the location of the bottom of the flap. You can then mark this spot on the door.

If your uPVC or composite door is made from metal (either aluminium or steel) you'll need be extra cautious when cutting it using power tools. The act of drilling into the metal may cause it to crack, especially if the area is toughened glass. This is why it's recommended to employ an expert glazier to install your cat flap in the glass pane. This will prevent the glass from breaking or becoming brittle. A Glazier is also able to provide you with a circular cat flap that is less likely to break and is safer for your cat to use.

Cut the Hole

A high-quality cat flap will come with a template drawing that you can use to mark the area on your door where the hole should go. If it isn't, you can make one yourself using the thin paper (tracing paper is the best choice). After the shape has been drawn on the door, you can utilize your spirit level to make sure that it is horizontal. This will allow the cat flap to be properly seated in the opening and stop it from being capable of sliding open or close.

Next, use your jigsaw, and cut the shape that has been written on the door. Make sure you are using a blade suitable for use on uPVC doors. Usually, it will be marked accordingly If not, ask the staff at your DIY store for assistance. Once the hole is made, place the flap section against it and open it, making sure that the flap moves easily. If it is bound at any point, use a filer or rasp to correct this.


It is also important to ensure whether there are no electrical cables or gas pipes inside the door you'll be cutting into since they could be damaged by your Jigsaw. Also, be aware of any handles or other fixtures that are on the door which must be removed to accommodate the cat flap. Be cautious not to scratch these objects during the process.

The majority of people who install the cat flap themselves have the standard solid uPVC door and will not be dealing with any of these issues. But, if your door is constructed of wood or has an ornamental panel that can't be removed, it will make it more difficult to complete the task.

For these types of jobs, it's worth getting expert advice from a cat-flap fitter. It is crucial to perform them correctly to avoid problems in the future. Making the wrong choice could cause the door to be damaged, which could cause the warranty to be invalidated.

Place the Flap

After you've made the hole drilled, place the flap in place to check whether it is able to open easily. If you notice any spots that catch or stick to the door, smooth them out using an sandpaper or hand file until it fits properly and opens without issue. Make sure that the flap is flush with the door.

If your tool doesn't have templates, you can use tracing paper that is thin, such as a piece of paper or Acetate. Place the paper on the door, and draw a line to indicate where the flap should be placed (this will serve as a cutting guide). Then, using the pencil lines you've made on the door, draw four screw holes in each corner of the flap. These are the screw holes you'll use to fit the flap into place.

Most uPVC door are solid and easy to cut. If the door is made of composite or GRP, it can be more difficult. If you're not comfortable with this, it is recommended that you hire a professional. They will also be able tell you if your door is suitable for installing an animal flap.

It is possible to install the cat flap onto composite doors. However, it's essential to verify with the manufacturer or a professional joiner prior to making any changes since any modifications to these types of doors may invalidate the warranty. If you decide to tackle the work yourself, bear in mind that this can be a messy job and could be dangerous.

For composite doors, you'll generally need to use a grinder or saw to cut through the door's frame rather than simply through the GRP. This is a risky task, and you'll require extra care to ensure that the door is not damaged. It's also worth noting that cutting a hole into any kind of glass door is a lot more difficult than making the same changes in a uPVC or solid wooden door.