Advice · 4 min read · Updated 6 November 2026

10 common catio mistakes UK cat owners make (and how to avoid them)

Short answer: The most common catio mistakes are using flimsy mesh such as chicken wire, leaving small gaps at the base or roof edges, forgetting shade and shelter, and giving the cat nothing to do inside. Others include no double-door entry, climbable structures near the edges, unsafe wood treatments and access that only works when you are home. Most are easy to avoid at the design stage.

1 to 3: Mesh, gaps and fixings

1. Using chicken wire or garden netting. Chicken wire is thin, stretches and can be pushed or chewed through by a determined cat, and the twisted wire can injure paws. Welded mesh of a decent gauge, galvanised or PVC-coated, is the usual choice.

2. Leaving gaps. Cats can squeeze through gaps far smaller than you would expect, often anything their head fits through. Typical weak points are where mesh meets the house wall, under doors, around downpipes and where the roof meets the sides.

3. Weak fixings. Staples alone can pull out over time. Mesh should be fixed with staples and battens or screws and washers, so it cannot be pushed away from the frame.

4 to 6: Comfort

4. No shade or shelter. A fully meshed roof in full sun gets uncomfortable in summer, and a fully clear roof can overheat. Provide part-solid cover, shade and a spot that stays dry in rain.

5. Nothing to do. An empty box gets ignored. Shelves at different heights, a scratching post, plants and a hiding spot keep a cat interested.

6. No water. Cats outside for long spells need fresh water in a stable bowl, kept in the shade.

7 to 8: Access and entry

7. Access only when you are in. If the cat can only reach the catio when you open a door, it will be used much less. A cat flap or window link lets the cat choose, which is when most cats get the full benefit.

8. No double-door entry for people. If you walk into the catio through a single door, a quick cat can slip past you. A small airlock with two doors, or a door that opens into the house rather than the garden, prevents that.

9 to 10: Hidden escape routes and materials

9. Climbable surroundings. Overhanging branches, trellis, water butts or a shed next to a cat-proof fence can give a cat a ladder over the top. Cut back or move anything within jumping distance.

10. Unsafe treatments. Old creosote, some oil-based preservatives and fresh paint can be harmful to cats that rub and lick. Use products labelled safe for animals once dry, and let everything dry and air fully before the cat goes in.

Quick pre-use safety check

Walk the full perimeter and push on every panel
Look for gaps at the base, corners and roof edges
Check that doors latch firmly and cannot be pushed open
Remove sharp screw ends, wire tails and splinters
Check nothing toxic is planted inside or just outside
Confirm the cat can get back indoors or to shelter

Supervise the first few visits. Cats are good at finding the one weak spot you missed.

Cost of getting it wrong

Fixing a badly designed catio often costs more than building it right first time, because mesh may need replacing and frames strengthening. If you are building it yourself, it is worth taking time over the plan, and if you are paying for a build, ask how each of these points has been dealt with.

Planning problems are just as costly, and usually come from skipping basic checks before work starts. Building over an inspection chamber, blocking an airbrick or fixing to a neighbour's fence without asking can all mean taking part of the catio down later. Check drains, vents, boundaries and any lease or planning restrictions first, then design around them.

Bonus mistakes with cat-proof fencing

Many of the same problems apply when the whole garden is being cat-proofed rather than a single enclosure, plus a few of their own.

Leaving gates unprotected, which are the most common escape point
Forgetting gaps under fences and gates, which cats can dig or squeeze through
Toppers fitted the wrong way, angled out instead of in
Missing short sections behind sheds, compost bins or greenhouses
Not cat-proofing low walls or garage roofs that join the boundary
Assuming a tall fence alone will stop a climbing cat

Walk the entire boundary slowly with the cat's eye view in mind. Anything a cat could jump onto within about 1.5 metres of the top of the fence is a possible launch point. Gates need their own toppers and a close-fitting bottom edge, and they should be self-closing if children or visitors use them.

Frequently asked questions

What mesh size should a catio use?

Many catios use welded mesh with holes of around 25 mm by 25 mm or smaller, which keeps cats in and most birds out. Very small kittens may need finer mesh. The gauge, or thickness, of the wire matters as much as the hole size, because thin wire can be bent or chewed. Galvanised or coated mesh lasts longest outdoors.

Can a cat climb out of an open-topped catio?

Most cats can. Unless walls are very tall with an inward-angled top designed to stop climbing, an open-topped enclosure is likely to be escaped. Walk-in catios are normally fully roofed with mesh or a mix of mesh and solid panels. Open-topped cat-proof fencing relies on special angled toppers or rollers instead.

Is pressure-treated timber safe for cats?

Modern pressure-treated timber is widely used for catios and pet housing and is generally considered safe once it has dried. Avoid old reclaimed timber that may have been treated with creosote or other older preservatives. If you stain or paint the frame, choose a pet-safe product and let it dry completely before use.

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