Catio materials explained: mesh, timber, roofing and fixings

Updated 6 November 2026 · By the Cat Enclosures team

Short answer: An escape-proof catio uses galvanised welded wire mesh, typically 16 or 19 gauge with 25 mm or 50 by 25 mm holes, fixed under timber battens on a pressure-treated timber or coated steel frame. A solid or part-solid roof of twinwall polycarbonate or felted boarding gives shelter, and the base is sealed with slabs, gravel boards or a mesh skirt so nothing can dig under. Chicken wire and staples alone should be avoided.

Catio materials explained: mesh, timber, roofing and fixings

Mesh: the most important choice

The mesh is what keeps your cat in and other animals out, so it is the last place to save money. Welded wire mesh, where the wires are welded at every crossing point, holds its shape and resists being pushed or chewed. Hexagonal chicken wire is twisted rather than welded, stretches easily and can be torn by a fox, so it is not suitable for cats.

Mesh type	Suitable for a catio?	Notes
Galvanised welded mesh, 16 gauge	Yes, strongest	Best for fox-prone areas and determined cats
Galvanised welded mesh, 19 gauge	Yes, common choice	Lighter and cheaper, fine for most cats when well fixed
PVC-coated welded mesh	Yes	Softer look and feel, coating protects against rust
Stainless steel mesh	Yes, premium	Longest lasting, especially near the coast
Chicken wire	No	Twisted wire stretches and tears
Plastic netting	Not on its own	Can be chewed through, best only for internal or high sections

Hole sizes of 25 mm square or 50 by 25 mm are widely used. Smaller holes stop kittens getting their heads through and stop rodents getting in. Wire gauge numbers run backwards, so a lower number means a thicker wire.

Galvanised before or after welding

Mesh that is galvanised after welding has the zinc coating applied over the welds, which protects the joints from rust. Mesh galvanised before welding is cheaper but the welds can rust first, especially in wet or coastal areas. For a structure meant to last ten years or more, galvanised after welding or PVC-coated mesh is the better choice.

Timber and frames

Most UK catios use pressure-treated softwood, often 45 by 45 mm or 50 by 50 mm for uprights and rails, with larger sections for big spans. Pressure treatment pushes preservative deep into the wood, which lasts far longer than a brushed-on coat. Any cut ends should be treated with an end-grain preservative, because cutting exposes untreated timber.

Keep timber out of direct contact with soil where possible. A frame resting on slabs, a concrete strip, gravel boards or post supports lasts much longer than one with posts sunk straight into the ground. Powder-coated steel or aluminium frames are an alternative, especially for balconies, and do not rot, though they cost more.

Roofing

Twinwall polycarbonate: lets light through, sheds rain and is light enough for most frames
Clear corrugated PVC or polycarbonate: cheaper, but noisier in rain and can go brittle in sun
Felted or shingled boarding: fully solid, good shade and shelter, heavier frame needed
Mesh roof with a covered section: most light and air, with a sheltered corner for bad weather

A roof falling slightly to one side, with a gutter where needed, stops water pooling or dripping onto shelves. In hot summers a fully clear roof can make an enclosure very warm, so add shade over part of it.

Fixings that cats cannot beat

Staples alone are the commonest weak point. A cat pushing against the mesh, or a fox pulling at it, can pop staples out over time. Mesh should be fixed under timber battens screwed through into the frame, or held with screws and large washers at close spacing. Joins between mesh panels should overlap and be fixed to a frame member, not just clipped together in mid-air.

Cut wire ends should be turned in or covered with a batten, so cats and people cannot catch themselves on them. Use exterior-grade or stainless screws so fixings do not rust out.

Sealing the base

Slabs or a concrete strip under the frame on all sides
Gravel boards with mesh fixed down to them
A mesh skirt turned inwards along the ground and pinned or buried
Checks at doorways, where gaps under the door are a common escape route

Cats rarely dig their way out, but foxes, rats and dogs will dig in, especially where food or litter is kept in the enclosure. A sealed base also stops the frame settling unevenly, which is what opens gaps at doors and corners over time.

Matching materials to your situation

There is no single best specification. The right choice depends on where you live, what visits your garden and how long you want the enclosure to last.

Situation	Suggested approach
Urban garden with regular fox visits	16 gauge welded mesh, sealed base, solid door and no gaps at ground level
Coastal or very exposed site	Stainless or PVC-coated mesh, stainless fixings, sturdier frame and bracing
Balcony or window at height	Powder-coated metal frame or light timber with secure fixings to suit the building
Calm single indoor cat	19 gauge welded mesh well fixed under battens is usually enough
Young, agile or escape-prone cats	Heavier mesh, full mesh roof or solid roof, no shelves near the roof edge
Rented home	Freestanding frame on slabs that can be taken apart and moved

Whichever materials you choose, ask your builder to list them on the quote, including the timber size, mesh gauge and hole size, roof material and fixing method, so you know exactly what you are paying for.