The no-drill frame
On a balcony with a ceiling or another balcony above, the catio can stand without a single hole in the building. Floor-to-ceiling tension posts, the adjustable kind used for room dividers and shelving, brace between the floor and the ceiling at each open corner; light 2x2 wall frames are clamped to them and meshed on the outside; the house wall and any side wall of the balcony close the rest. This 6 ft x 4 ft section of an 8 ft balcony, with the right side against a wall, needs:
| Item | Quantity |
|---|---|
| 2x2 x 8 ft | 11 boards |
| 4 x 8 ft plywood, 3/4 in (sold as 23/32 in) | 1 sheet |
| 1/2 in hardware cloth, 19 gauge, galvanized, roll 24 in x 100 ft | 1 roll |
| Exterior wood screws, 3 in | 88 screws |
| Exterior wood screws for the plywood, 1 1/4 in | 36 screws |
| Staples, 1/2 in or longer, for a heavy-duty stapler | 303 staples |
| Washer-head screws or screws with fender washers, 1 1/4 in | 52 screws |
| Hog rings or stainless zip ties for overlaps between members | 81 ties |
| Floor-to-ceiling tension posts, adjustable to 8 ft | 2 posts |
The tool marks nothing in this design as fixed to the building, and the shopping list has no wall fixings. Open the no-drill design to set your balcony's width, depth and ceiling height.
Without a ceiling above
Tension posts need something to push against, so on a top-floor balcony or a deck the frame stands on its own: a freestanding frame with a mesh roof, standing on the balcony floor. The tool's balcony type without a ceiling builds it with its own roof bars and checks that there is a top, because there should be no openings a cat could squeeze through, even on top (Humane World for Animals, catios). It has 24 pieces cut from 14 boards. Open the design without a ceiling.
Check before you build
- Your lease and your building's rules. If you rent, check with your landlord or management company first (Humane World for Animals, catios). The tool gives no permit or legal advice; it does show a design you can take down without a mark.
- The railing is not a wall. Mesh the open sides from the floor to the ceiling, railing included: a cat can climb a railing and squeeze between its bars.
- The gaps at the floor and the ceiling. Tension posts sit tight, but frames can leave a gap against a sloping balcony floor. The tool holds every gap to the short side of your mesh opening, never more than 1 in; type your widest gap and it checks it.
- Sun and heat. A balcony ceiling shades the floor at midday, but low sun reaches in under it. The shade check uses your latitude and the way the balcony faces; keep water out and the door into your home open on hot days (Catio Spaces, heatwave tips).
Shelves on a balcony catio
With 3 shelves in an 8 ft high space, the tool steps them 16 in apart, inside the 12 to 18 in suggested for older or cautious cats (The Refined Feline, shelf spacing). The shelves hang on the frame, not the building, so they come down with it.