We recently took in a stray kitten and to save our furniture we decided he needed his own to climb on. After looking online and in stores, we decided we could make one for a bit less money. As a fan of Instructables, I searched the site, but didn't find anything like what we were looking for. A search found some sites selling plans, but we reverse engineered some pictures and designed a plan of our own for a carpeted, four-level cat tree (five if you count the base level). We went to the hardware store (we have a Home Depot right down the street) and purchased lumber, carpet, sisal rope, a hook for hanging a toy on a string, and some spray cans of adhesive. We were unable to find dowel screws, so a trip to another hardware store, Menard's, netted us some more (and cheaper) rope and some dowel screws to connects the pole sections together. We already had the wood screws for attaching the poles to the base and the top, but those can be purchased as well. Our total was a little more than $100.

Step 1: Materials & Tools

Materials:

1 - 4ft x 8ft x 3/4" Particle board for the base and two rectangular levels
1 - 2ft x 4 ft x 1/4" MDF board for the triangular levels
4 - 2" x 2" x 8ft boards for the posts
3 - 50ft of 1/4" - 3/8" Sisal rope to wrap around some of the posts
1 - 3ft x 12ft piece of carpet
2 - cans of spray adhesive for gluing carpet platforms and poles
9 - 2" or 2 1/2" long dowel screws (the 2" long ones were labeled hanger bolts, and we only got them because the store didn't have enough of the longer, dowel screws)
18 - 2" wood screws

Tools:
Tape measure
Electric drill & drill bits
Utility knife
Circular saw
Pliers

We had the lumber cut into the following sizes by the staff at the store for free to make it easier to transport home:
Particle board cut into 30" x 4ft sections, with a little left over
MDF board cut into a 18" x 24" section with some left over
The 2x2's cut in half, to make 8 - 4ft boards.

Step 2: Prepare the Boards

Our layout consists of top-down views of each level, showing where poles are needed to support the levels, and how many of which sizes we need. We cut the boards according to our layout using a circular saw, so that we had a particleboard base of 30"x30" (or a little bit bigger) and another 30"x30" we cut in half, for the two 15"x30" rectangular, particleboard levels (the first level and the top level) and then an 18"x18" square of MDF that we cut in half into two right triangles for levels 2 and 3.

Step 3: Prepare the Posts

We decided to make the calculations easier by making each of the lower levels 12" high. So, for the poles that would be supporting a 3/4"-thick particle board level, they needed to be 11 1/4" tall. And the poles that would be supporting a 1/4"-thick MDF level, the poles needed to be 11 3/4" thick. To avoid a few extra cuts, we decided the top level would sit upon the 4ft high 2x2 poles, so the posts reaching the top level didn't need to be adjusted for the thickness of the top level. We didn't account for carpet thickness, figuring we would be okay if it was a little crooked. Find 3 posts that are about the same length for the full-length posts. For the remaining posts, we calculated the length of the pole sections, subtracting the thickness of the board that would be on top of it. As can be seen in our plans, we needed:

3 - 4ft poles
6 - 11 1/4" poles
5 - 11 3/4" poles
2 - 12" poles
1 - 23 3/4" pole
1 - 36" pole

We cut the poles down to the right sizes using a circular saw. Once they were cut, we made sure to mark the size on the ends so we would know which poles were which after carpeting them.

Step 4: Wrap Posts in Rope

You may want to do this step before or after the carpeting step, in case you run out of carpet, or find that gluing carpet to poles is too sticky and time-consuming. Wrap one or more of the posts in sisal rope. We found that 150ft of 1/4" sisal rope was enough to cover two 4ft poles. 50ft of 3/4" sisal rope covered the 3ft pole with a little bit to spare.

Step 5: Prepare the Carpet

We cut two sections at 3ft each off the 12ft x3ft strip we purchased for the base and the rectangular levels so that we'd have a couple extra inches of carpet around the edges of the boards to secure to the bottom, leaving us a 6ft x 3ft. Then we mapped out the cuts for the poles and the triangular levels. Even though the poles are 2" on each side, it took about 9" of carpet to go around the poles.

Follow the directions for the adhesive. We did the gluing outside, and stood on carpeted boards and poles while the adhesive set. For the boards, we first glued down the carpet to the top, and then once the top was set, wrapped the carpet around to the bottom and glued it down until that side was set. You may need to trim a bit of carpet from the corners of the boards. We trimmed it from the tips of the triangles, since it was quite thick, and used extra glue to make sure it held well.

For the poles, we found it best to line them up in the direction that the strands of carpet ran, otherwise when we cut it from the main piece of carpet, we might have runs going around the pole, instead of down the seam area. We glued one side of the pole down at the edge of the carpet, and held it until it was set, and then turned it onto the next side, and glued that side down until it was set, repeating until all four sides were done. Then we cut the carpeted pole off of the main piece of carpet. Note: we did not try to cut out pieces of carpet for each individual pole, figuring that there wasn't much extra carpet, and we didn't want to end up with the wrong size or shape because we glued at an angle, or did not glue the carpet down it tightly enough.

Step 6: Assembling the Cat Tree

We started by drilling a pilot hole in the center of the top and bottom of each pole so that when we put in the wood or dowel screw, we would be sure that we didn't end up going in at an angle. We then began building the cat tree by attaching 6 11 1/4" poles in positions 1, 2, 4, 5, 7, and 8 to the rectangular board for level 1. To do this, we first lined up where we wanted to attach the poles and drilled holes into the board for level 1. For the pole in position, we drilled a pilot hole for one of the wood screws, but for the other poles, we drilled a hole through the board for the dowel screw to fit through and using either pliers or the drill, screw the dowel rod into the top end of the poles for positions 1, 2, 4, 5, and 8. For the pole in position 7, screw it into the board for level one with a wood screw. Then line up the poles with level 1 on top to the base, and screw in the poles into the base using wood screws.

Using the same method, we attached the triangular levels to the poles that support them underneath, and made holes in them for the dowel screws, and screwing in the new poles above as we added the levels. Finally, we added the top level.

Step 7: Finish Assembling

Once all the levels are attached and all the connections are tightened up, we let the cat enjoy it. We've tightened the connections every couple months, but it's still very sturdy and we're all pleased with it. We hope you can enjoy your own cat tree too!