How to install a cat door: steps for wooden vs glass doors

install a cat door

This guide outlines the steps to install a cat door — sometimes called a ‘cat flap’ — into wooden doors, and the steps for glass doors.

A cat door, also known as a pet door, is a small opening in a door or wall that allows pets, usually cats, to enter or exit a house or specific area freely without requiring human intervention. Below you will find the benefits, and step by step instructions for cat flap installation.

Benefits to install a cat door

There are several benefits associated with installing a cat door…

Convenience for Your Cat

A cat door allows your feline friend to come and go as they please, which can be particularly beneficial for indoor-outdoor cats or cats that need access to a litter box or food while you’re away.

Physical and Mental Stimulation

Cats are naturally curious and independent animals. A cat door provides them with the opportunity to explore the outdoors, engage in physical activities, and experience new stimuli, helping to prevent boredom and potentially reducing behavioral issues.

Reduced Accidents

If your cat has access to the outdoors, a cat door can reduce accidents inside the house related to needing to go outside to relieve themselves. This is especially helpful if you’re not always available to let your cat out.

Health Benefits

Cats that have the ability to roam outdoors might be more active, which can contribute to better physical health and weight management.

Safety and Security

Outdoor cats that have a cat door can quickly return to the safety of the house if they sense danger or feel threatened by other animals.

Freedom for You

A cat door can free you from the responsibility of constantly letting your cat in or out, which can be especially useful if you have a busy schedule or if your cat tends to wake you up during the night to be let out.


Cats are naturally solitary animals that value their independence. A cat door allows them to maintain their privacy and territory without relying on human assistance.

Reduced Scratching and Meowing

Cats that want to go outside but are confined indoors might resort to scratching at doors or windows and meowing excessively. A cat door can alleviate these behaviors.

Litter Box Access

If your cat’s litter box is located outside, a cat door provides convenient access, reducing the likelihood of accidents if your cat can’t reach the litter box in time.

Climate Control

Some cat doors come with insulation and weatherproofing, helping to maintain a comfortable indoor temperature by minimizing drafts and energy loss.

How to install a cat door

It’s important to note that there are different types of cat doors available, including manual flaps, magnetic or electronic locking doors, and even smart doors that can be controlled remotely. The right choice for you will depend on your specific needs and your cat’s habits. Additionally, if you live in an area with potential dangers such as predators, busy roads, or adverse weather conditions, you should carefully consider whether a cat door is suitable for your cat’s safety and well-being.

How to install a cat door into a wood door

Installing a cat door into a wooden house door can be a relatively straightforward DIY project. Here’s a step-by-step guide to help you through the process:

Materials You’ll Need

  • Cat door kit (make sure it’s appropriate for wooden doors)
  • Measuring tape
  • Pencil
  • Screwdriver or drill
  • Jigsaw or keyhole saw
  • Sandpaper
  • Level
  • Screws

Installation Steps:

Choose the Location:
Decide where you want to install the cat door on the wooden door. Choose a location that’s easily accessible to your cat and consider factors like your cat’s height and any obstacles on either side of the door.

Measure and Mark:
Measure the height of your cat’s belly from the ground and use this measurement to determine the height at which the bottom of the cat door should be placed. Mark the top and bottom edges of the cat door on the door with a pencil.

Trace the Template:
Most cat door kits come with a template. Place the template on the door, aligning it with your markings. Trace the outline of the template onto the door.

Drill Holes for Starting the Cut:
Use a drill to create holes at each corner of the traced outline. These holes will serve as starting points for your jigsaw or keyhole saw.

Cut along the Traced Outline:
Use a jigsaw or keyhole saw to carefully cut along the traced outline. Take your time and follow the lines as accurately as possible. Wear safety goggles to protect your eyes from any wood particles.

Sand the Edges:
After cutting, the edges might be rough or uneven. Use sandpaper to smooth out the edges and create a clean opening for the cat door.

Assemble the Cat Door:
Follow the manufacturer’s instructions to assemble the cat door components. This typically involves attaching the frame and flap assembly.

Install the Cat Door:
Slide the assembled cat door into the opening from the interior side of the door. Ensure that it fits snugly. Use a level to make sure the cat door is straight and aligned.

Secure the Cat Door:
Once the cat door is aligned correctly, secure it in place using the screws provided in the kit. Follow the manufacturer’s instructions for screw placement and tightening.

Test the Door:
Open and close the cat door flap several times to make sure it operates smoothly and that your cat can easily go through it.

Training Your Cat:
After installation, you might need to help your cat get accustomed to using the door. Gently encourage them to go through the flap by holding it open initially, and then gradually letting it close as they become more comfortable.

How to install a cat door into a glass door

Installing a cat door in a glass door can be more challenging than installing one in a wooden door due to the delicate nature of glass. If you’re not experienced with working with glass, it’s recommended to seek professional help to avoid damaging the door or glass. That being said, here are the general steps for installing a cat door in a glass door:

Materials You’ll Need:

  • Cat door kit (designed for glass doors)
  • Measuring tape
  • Pencil
  • Masking tape
  • Glass cutter or glass saw (if necessary)
  • Safety goggles
  • Silicone sealant or similar adhesive
  • Screws or bolts (as provided in the kit)

Installation Steps:

Choose a Suitable Location:
Determine where on the glass door you want to install the cat door. Make sure it’s at an appropriate height for your cat and consider any obstructions or structural elements within the glass.

Measure and Mark:
Measure the dimensions of the cat door frame and mark the outline on the glass door using a pencil. You can also use masking tape to create a guide for cutting.

Prepare the Area:
Ensure the area around the marked outline is clear and clean. Place drop cloths or old towels on the floor to catch any glass fragments.

Cut the Hole (if necessary):
If your cat door kit doesn’t fit the dimensions of the glass, you might need to use a glass cutter or glass saw to carefully cut along the marked outline. Wear safety goggles to protect your eyes while cutting. If you’re not comfortable cutting glass, consider hiring a professional glazier to do this part.

Assemble the Cat Door:
Assemble the cat door according to the manufacturer’s instructions. This typically involves attaching the frame and the flap assembly.

Apply Silicone Sealant:
Apply a thin, even layer of silicone sealant or a similar adhesive around the outer edge of the cat door frame. This will help create a watertight and airtight seal between the cat door frame and the glass.

Insert the Cat Door:
Gently insert the cat door assembly into the hole you cut or the prepared opening. Press it firmly against the glass to ensure good adhesion with the sealant.

Secure the Cat Door:
Follow the manufacturer’s instructions to secure the cat door in place. This usually involves using screws or bolts provided in the kit. Be careful not to overtighten, as you don’t want to crack or shatter the glass.

Clean Up:
Wipe away any excess silicone sealant that may have squeezed out during installation.

Let it Cure:
Allow the silicone sealant to cure according to the manufacturer’s recommendations before allowing your cat to use the door.

Test and Train:
Test the cat door to ensure it’s functioning properly. Encourage your cat to use the door by gently holding the flap open and allowing them to pass through. Positive reinforcement and patience can help your cat become comfortable using the new door.


Remember to consult the specific instructions provided by the cat door kit manufacturer, as installation steps can vary slightly between different brands and models. If you’re not comfortable with DIY projects or if you encounter any difficulties, you might want to consider seeking assistance from a professional handyman or carpenter.

Photo by Mervilili