Many homeowners would like to give their cat access to a specific room in the house while keeping other animals, like dogs, out. By installing a cat door, this can be accomplished with ease.
Initially, it may seem tricky to accomplish this feat, largely because interior doors tend to be hollow core. But, with the right tools and a little bit of time, most homeowners can complete this project successfully, letting them install a cat door in a hollow core door located anywhere in their house.
Read The Fitting Instructions
Every cat door kit should come with a set of fitting instructions. This will tell you how big the hole in the door needs to be for a successful installation, as well as how high off the lower edge of the door the hole needs to be.
Review the included fitting instructions to find these measurements, then move on to the next step.
Locate The Center Of The Door’s Width
In most cases, homeowners prefer to install a cat door in the horizontal center of the door. To do this, you need to take the tape measure and record the width of the door along the lower edge. Then, divide that number by two.
Take the new measurement and, using the tape measure, located that point on the lower edge of the door. Make a small pencil mark so you can reference it later.
Measure The Height Of The Lower Edge
To make sure the bottom edge of the cat door opening is in the right place, you need to measure up from the bottom of the door.
Take your tape measure and align it with the center mark from the previous step. Find the proper height, based on the manufacturer’s instructions, and make a pencil mark so you can locate where the bottom edge needs to be.
Draw The Lower Edge
First, check the fitting instructions to find the required width for the hole and divide it by two. Then, using your tape measure, measure out from the pencil mark in the previous step to the needed halved-width and make a new pencil mark to designate the length. Repeat the process in the other direction.
Now, you should have three points that make approximately a straight horizontal line. Take your level and align it with the center pencil mark. Adjust it until it is level (not until the existing pencil marks connect, as the right and left marks may be slightly off).
Next, draw a straight line, using the level as a straight edge, in the appropriate length based on the width measurements, using your right and left pencil marks as reference points.
You should now have a level, straight line designating the lower edge of the cat door opening.
Add The Right And Left Vertical Lines
Take another look at the fitting instructions and see how tall the hole needs to be in order to install the cat door. Then, take your square and, using your pencil, mark the 90-degree angle on the right and left side by drawing up from the lower line a two or three inches.
Use the tape measure and measure up from the lower line, using the new vertical line you created in this step to help keep it straight. Mark the needed height with your pencil. Repeat the process on the other side.
Take your level and align it with the vertical line coming off the 90-degree angle. Level it out then use it as a straight edge to draw a line to the needed height measurement, referencing the mark you made a moment ago. Repeat the process on the other side.
Mark The Upper Edge
Using the level or a straight edge, connect the top points of the vertical lines together with your pencil.
You should now have a rectangle drawn on the door in pencil designating the opening you need to install the cat door.
Drill Starter Holes
To give you enough room to start cutting out the opening, you’ll need to take a drill, attach a bit that is large enough for the jig saw blade to fit through, and create starter holes at each corner of the rectangle.
Take the drill and create a hole in just one side of the door. Since hollow core doors don’t have much support in the center, trying to drill straight through the other side could damage the panel.
Cut Out The Opening
Using the jig saw, insert the blade into one of the starter holes then cut out the opening using your pencil lines as guides. Make sure to keep the blade at a 90-degree angle to the door, and only cut through the single panel.
Repeat Steps 2 Through 9
Now, you should have a rectangle cut out on one side of the door. You need to repeat steps 2 through 9 on the other side of the hollow core door to finish creating the opening.
Sand The Edges (Optional)
Once you have a hole through the door, you may need to sand the edges of the opening if they are rough. Generally, this step is optional, so you can bypass it if the edges are relatively clean.
Install The Cat Door
With the opening created, you can now install the cat door in your hollow core door per the manufacturer’s instructions.
Each cat door kit may be slightly different, so you need to refer to any included materials for securing the frame and adding the flap.
Test Your Cat Door
After you install the cat door in the opening, take a moment to test it. Using your hand, make sure the flap swings properly from both directions. If you have a security door, typically a metal panel that slides into the frame, you can test it as well.
Once the test is complete, you’re finished installing your cat door.
By following the instructions above, you should have a functional cat door installed in your hollow core door, giving your cat the ability to move freely between rooms regardless of whether you’re there to let them in.