Why Indoor Cats Deserve a Taste of the Outdoors
Indoor cats live significantly longer than outdoor cats — an average of 12 to 18 years versus 2 to 5 years for cats with unrestricted outdoor access. But keeping cats inside comes with a trade-off: many indoor cats develop boredom, obesity, and behavioral issues from a lack of environmental stimulation. A catio bridges this gap perfectly, giving your cat access to fresh air, sunlight, bird-watching, and the sounds and smells of the outdoors without any of the risks that come with free roaming.
The word “catio” — a portmanteau of cat and patio — covers everything from a small window box enclosure to a sprawling backyard structure with multiple levels, tunnels, and climbing features. And here’s the best part: you don’t need to spend thousands of dollars or hire a contractor. A functional, attractive catio can be built in a weekend for as little as $150 to $300 in materials, depending on the size and design you choose.
Choosing the Right Design for Your Space
Window Box Catios
If you’re working with limited space or renting, a window box catio is the simplest and most affordable option. These small enclosures attach to an existing window, extending outward like a bay window for cats. Your cat accesses it through the open window, and the enclosure is typically 2 to 4 feet wide, 2 feet deep, and 2 to 3 feet tall — enough room for one or two cats to sit, stretch, and enjoy the view.
A basic window box catio can be built from a few pieces of lumber, hardware cloth or welded wire mesh, some screws and brackets, and an afternoon of work. Materials cost runs $50 to $100 for a simple design. The main structural consideration is secure attachment to the window frame or exterior wall — the enclosure needs to support your cat’s weight with a generous safety margin.
Patio or Deck Catios
If you have a patio, deck, or balcony, you can convert part or all of it into an enclosed cat space. This is often the easiest approach for homeowners because the existing structure provides the floor and potentially one or more walls — you’re just adding screening and a roof.
Frame the open sides with 2×4 lumber and cover them with hardware cloth (the half-inch variety is strong enough to resist most predators and small enough that cats can’t push through). Add a screened roof or attach the enclosure to your home’s exterior wall for weather protection. A patio catio for a 6×8-foot space runs $200 to $500 in materials, and the project takes a weekend for someone comfortable with basic tools.

Freestanding Backyard Catios
The most ambitious option is a standalone structure in your yard, connected to the house via a cat tunnel or cat door. These range from simple 4×6-foot walk-in enclosures to elaborate multi-level structures with climbing walls, bridges, and garden beds. Freestanding catios typically cost $300 to $800 in materials for a moderate-sized build, plus the cost of a cat door or tunnel connection to the house.
The advantage of a freestanding catio is design flexibility — you can place it wherever you want in your yard, size it to your space, and add features like real grass patches, potted cat-safe plants, and elevated platforms for bird-watching. The disadvantage is that it’s a more involved construction project and may require a building permit depending on your local regulations.

