This DIY cat castle gives your favorite feline a cozy place to sleep, play, perch, and keep watch over the kingdom. Built primarily from MDF and plywood, this fun woodworking project transforms a relatively simple cat house into a miniature castle complete with windows, towers, removable roof panels, crenellated parapets, and decorative corbels.
One of the great joys of woodworking is building something for someone else. Of course, people aren't the only ones who appreciate a shopmade gift. The enclosed keep of this castle provides a comfortable place for a cat to curl up, while the windows and sturdy plywood roof create perfect spots for watching the world go by.
The design is versatile, too. While we built it as a wooden cat house, the castle could also work for a small dog. Remove the roof panels and it could even become an imaginative playset for younger children.
What really transforms this project from a simple MDF box into a castle is the decorative trim. Crenellated parapets give the walls and towers their medieval profile, while rows of corbels provide architectural detail underneath. These small additions are a great example of how creative trim can completely change the character of a woodworking project. You can make the parts with traditional woodworking tools, or use the available DXF files to cut them with a CNC.
A pair of roof panels enclose the central keep. Finger pulls make them easy to remove, yet the plywood still makes a sturdy perch.
The keep and towers are decorated with routed crenellations above and corbels below, completing the classic look of this castle.
AN INTERLOCKING KEEP
The first thing to address on the castle is building the main body, or “keep,” of the castle. As you can see, the keep is made from four pieces of MDF. These are connected by lap joints (detail ‘b’). Additionally, the sides and front will need a little cutting to create the doors and windows. But, first things first: size the pieces of MDF.
LAPPED CORNERS
After cutting the keep pieces to size, next I looked to their joints. I made these lap joints using a router and a set of scraps as a guide. However, I needed to do a little work at the band saw before that.
First was cutting the notches shown in detail ‘b’— with a wide blade it was easy to get a clean cut. I then used a couple of curving cuts through the waste of the slot to remove most of the MDF. The more MDF you get out of the way now, the less you’ll have to worry about breathing in later on.
ROUTING THE PORTALS
Next on our keep comes the door in the front, as well as the windows along the sides (detail ‘a’). We’ve provided patterns that you can use to make templates. I used one template for the doors and another for the windows. The waste can initially be removed from the portals with a jig saw, but be sure to leave a little waste beside the layout lines.
Then, you can use a flush-trim bit in your router to make crisp lines that sit flush with the template. Now, the assembly can be fit together. The slots interlock, allowing you to break down the castle for transportation. As long as the four keep pieces fit together snugly, you’re ready to move on.
KEEP DETAILS
Aesthetics are important, and this castle doesn’t slouch on the fine details. To begin some of this work, we’ll start with an operation similar to what we just did.
ENTRANCE ARCH
The entrance arch is made quite similarly to routing the portals. As with the door, I first used a jig saw to remove most of the waste from within the arch and free it from the larger sheet. Then I used double-sided tape to stick the MDF to a backer board and routed along a template to clean up the inner and outer radii.
Sticking the arch in place doesn’t take much. Apply a little glue to the back of the arch, then press it to the keep front, centered on the door cutout. Given how light this piece is, clamps aren’t necessary. I found it easiest to simply hold the arch in place until the glue began to go off.
REMOVABLE ROOF
A pair of removable roof panels completes this portion of the cat castle. These panels are plywood. Plywood makes for a stiff and stable cat platform as well as a roof. Before cutting these two pieces to size, I started with one overly wide blank. This allowed me to use a Forstner bit to create the thumb pulls shown in the main illustration, then I simply ripped the blank in half.
Lastly, to make sure these panels will accommodate the towers you’ll be adding next, you’ll need to create the uniquely shaped notches shown in detail ‘a.' I accomplished these at the band saw.
THE MIGHTY TOWERS
While your cat may enjoy the rather plain keep assembly so far, there are a few additions that will make this box a true castle.
TOWER WALLS
We’ll begin with towers — specifically, the walls. Detail ‘b’ shows how the tower walls fit together. After cutting the front, back, and side pieces to size, cut the grooves in the fronts and backs that will accept the sides.
Next up are the slots that allow the towers to fit over the keep walls. I made these by routing out the waste, then cleaning up the corners with a chisel. Keep in mind that these slots will only be on the back and inner side piece of each tower.
TOP & FILLER
Two sets of parts remain on the towers: the tops and the fillers. Fit the towers together when sizing these pieces to be sure the fillers are snug and the tops sit flush. After sizing, drill a hole in the center of each top for the banners added later. Finally, you can assemble the towers and slip them over the keep sides.
PARAPETS & CORBELS
The towers add a lot to the keep, but what will really sell it as a castle are the parapets (the rectangles) and the corbels (the arches). These pieces are shaped trim. While they take a bit of time to make, they’re not difficult.
PARAPETS
Although the parapets differ in length, the depth of the embrasures (the gaps) are the same. This means they are created quite quickly with a dado blade and a crosscut sled. After dadoing the lengths of parapets, cut them to fit in their places.
When fitting the parapets on the towers, start by centering the front and back ones over the tower sides, then use them to help fit the side parapets in between. To attach these pieces, I simply used a bit of glue and hold them in place until it sets.
CORBELS
Making the corbels is somewhat similar to the parapets. However, to establish the radiused ends, I used a Forstner bit at the drill press to create a series of holes in the corbel blanks. Now you just have to take care of the waste in between. You could rout it out, but since I already had a dado blade and sled in place, I narrowed down the dado stack and cut the waste at the table saw.
Sizing and attaching the corbels work the same as the parapets. Lastly, we painted the castle and added the flags.
Correction / clarification: Window Corbels should be (6) 1/4" MDF - 3/4" x 1 3/8"
