15 DIY Cat Door Window Insert – How To Build

Jane Foster

DIY Cat Door Window Insert

Hello, today I would like to share with you how to build a DIY cat door window insert. This is a great project for people who want an easy way in and out of their home while letting the cat stay inside. If you are looking at this post, then chances are your kitten is already starting to climb up some windows and try to jump in your bedroom window, so this might just apply to you!

At some point we all have been in a situation where the cat is outside and you have no idea what to do. We find this to be very stressful and sometimes even dangerous, especially if our pets are young and not fully grown up. The best way to tackle this issue is by installing a cat door window insert. It’s easy, you don’t need special tools or skills, and it can improve your relationship with your feline friend for years to come.

See also: 15 Scratching Posts For Cats

1. DIY Cat Window With Door Insert

If your catio is right behind your window, it will be nice to have a door inserted in your window for your cat to have easy access to the catio anytime. Before making the door insert, you need to measure the inside of the top track to the inside of the bottom track. Then, gather your materials and cut them to length. However, you need to shorten the length to enter the bottom track. Get a pine and paint it to your desired color. After that, cut it to length and use it to build the frame for the foot insert. But, ensure that the pine is wide enough for pet door cutout in case you have larger cats.  

2. Cat Window Door Insert DIY

Choosing the materials for your cat door insert is very important because most of the materials might not be durable enough and they can break at any time. In this guide, you’ll learn how to make a sturdy yet amazing cat door insert that will allow your cat to move freely in and out of the house. 

3. DIY How To Install Cat Door In Window 

The materials needed for this cat door window insert include pine board, speed square, compound miter saw, pencil, small cat door, clamp, and tape measure. The first step after gathering the materials and tools is to remove the window slide and measure the length and width of the window. After that, the next step is to measure and cut the pine board for the window frame. Then, install the frame with screws and assemble the cat door. 

4. Custom Cat Window Door Insert with Solid PVC

If you’re looking for something a little classy and elegant for your cat,  this custom cat window door insert is amazing. The idea behind the window door insert is very simple; an amazing cat window door with a solid base and a locking flap! The solid base could be made from either PVC or plexiglass. The whole window insert is removable and it can be reinstalled as quickly as possible. Since it is custom, you have it in different sizes; 4-way locking, larger size flap, or microchip cat flaps.

5. DIY Cat Door For Window

DIY Cat Door Window Insert

Are tired of letting your cat in and out of the house all the time by yourself? The best solution to this is to install a cat door to your window. Having a stair attached to your cat window door makes this idea the perfect project for you if your window is located at the top of the house. The amazing cat window door with stairs is made from scrap wood and plexiglass. dougcone

6. DIY Sash Cat Door Insert

DIY Cat Door Window Insert

If you abhor the idea of cutting holes until doors or windows to install a cat door, then this sash cat door insert is for you. It is so easy to put together and easy to disassemble. There are varieties of sash cat doors out there that can make a good fit for your window. All you have to do after getting one is to raise the window panel, place the sash cat door and close the panel on it.   Extremediy

7. DIY Pet Door Window Insert

DIY Cat Door Window Insert

Cat door installation in your window will boost your cat’s confidence as it can go in and out of the house anytime by itself. The door insert is made from extruded polystyrene (XPS) foam, and when appropriately installed it gives better thermal insulation than plastic or aluminum window door inserts. instructables

8. DIY Cat Flap Custom Build Cat Door For Window 

This custom build cat door is installed directly into your window track, you don’t need to cut the door. The cat door insert is totally removable. You’ll need the exact measurement of your window so you can have a cat door insert that fit well. The instructor will show you how to take the proper measurement and how to make the order easier and more comfortable. Check out what the instructor has to say in this video below. 

9. DIY Catio Window Door 

All that you need for this catio window door include wood, handsaw, miter saw, router, tape measure, power drill, drill bits, table saw, wood glue, screws, clamps, and a mallet. Once you have all these materials and tools, you’re good to go. The first step is to measure the length and breadth of the catio window. After that, cut the wood into pieces as shown in this guide and prepare it. By preparing, I mean, let it pass through the router, sand them, and drill holes in them. Then, you can start assembling. 

10. How to Install Aluminum Sash Window Pet Door 

When it comes to cat window doors, a very simple yet classy idea is the aluminum sash window pet door! All you have to do is to get the pet window door. The window door comes with a frame and a roll bumper seal. Raise the sash window the panel to fill open the window and place the pet door assembly into the center of the windowsill. 

After that, gently turn the sliver knobs anti-clockwise to release the spacer and spring-loaded.  Then, turn the silver knob clockwise to tighten it. Repeat the processes for both sides. After that measure the top of the pet door assembly and use that to cut the number of seals needed for the installation. 

11. Sash window Cat Door Installation 

Installing a sash window cat door is pretty simple and fast. The window door comes with a spring load on both sides such that you can adjust it to any length you want. All you have to do is to place the sash pet door on your window Franck and close the window on it. 

Then, get a piece of leather strip rolled up in foam and insert it in-between the sash pet door and the window. Also, insert the leather strip at the bottom of the pet door to have a better seal with the window frame. It also comes with a flexible draught stopper; it works like a squeegee blade. 

12. Easy DIY Cat Window Door Access 

What do you think about this removable cat window door? Amazing right! You can leave it on during the day and take it off when night comes. The whole window access is cheap and costs less than $5  using retail price sleeves, heavy-duty tape, and clip strip. All you have to do is to align the price sleeves to the opening of the clip strip and clamp the clip on it. Then, cover the back of the clip strip with tape and attach it to the window. It is as simple as that; it doesn’t take up your time, energy, or money. 

13. Building Cat Window Door 

Opening the door or window for your cat to go out is not a very good option, you should provide a means for the cat to move freely on its own. That’s why a window cat door is important; it allows your cat to go in and out of the house by itself. This cat window door is made of ¾” pine and plexiglass. 

Cutting plexiglass can be tricky and you need to be careful while at it. One of the effective ways of cutting plexiglass is by scoring it along a straight edge with a sharp knife. Score the plexiglass deep to make it easier to break. Once you’re done scoring, clamp the glass to the tip of a working bench and break it as shown in this video.  

14. How to Build a Cat Window Door

One of the features of an amazing cat window door is that it must swing in both directions, another thing is that it would always stay closed when not in use. The ability of the door to swing in both directions will prevent the cat from getting hurt, especially the tail. 

To make the swinging hinges, refer to this tutorial and you’ll have detailed instructions on how to put them together. Among the materials used for this cat door window include wooden dowels, black spray paint, plexiglass, screws, and a sander.  If your cat door is lacking any of the features above you can check the vide above for how to make this DIY Cat Door Window Insert. 

15. DIY Pet Door For Windows 

One of the cheapest ways to install a cat door in Windows is to use a screen. You can order the screen at the cheapest price from Home Depot or any other store. The first thing you need to do is to disassemble the screen (take care of the two raised corners at the bottom and two spring clips at the top of the screen), then measure the length and width of the window to the size of the frame needed for the cat door. 

After that, use the measurements to cut the frame from the screen part. Once you’re done cutting, attach the two raised corners to the bottom piece and the two spring clips to the top pieces. 


Give your cat the freedom they deserve! The idea of a cat door means freedom for both you and your cat they are so easy to build within a small time. All you need is a little guidance and that is exactly what the above-listed guides are doing; letting you on on the trucks if making amazing cat doors in a short period and for a cheaper price.  

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