Cat window boxes and balcony enclosures

Cat window boxes and balcony mesh enclosures for flats and small homes, giving indoor cats safe fresh air. What's involved and typical UK prices.

In short: A cat window box is a small mesh enclosure fixed outside an opening window, and a balcony enclosure uses mesh panels to close in a balcony so a cat cannot fall or climb out. Both are aimed at flats and homes with little or no garden. A fitted cat window box typically costs around £250 to £700 in the UK, and a balcony mesh enclosure around £400 to £1,500.

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For many indoor cats in flats, a window or balcony is the only realistic way to get fresh air, sunshine and something to watch. A window box gives a cat a secure perch outside the window, with mesh on all sides and a solid top for shelter. It is small, but cats use it intensively, especially to watch birds and street life. A balcony enclosure goes further, enclosing the whole balcony from floor to ceiling so a cat can use it as a small outdoor room.

Falls from height are a real risk for cats, and they do not always land safely, so balcony mesh needs to run the full height with no gaps at the top, sides or base. Fixings have to suit the building, which might be concrete, brick, render or a metal balcony frame. Many flats are leasehold and many are rented, so the freeholder's or landlord's consent usually comes first. Designs that clamp or tension into place rather than drilling can help get that agreement.

What is included

Measurement of the window or balcony and its fixing points
Frame sized to the opening, with a solid or part-solid top
Welded wire mesh on all open sides with no gaps at joins
Fixings chosen for the wall or balcony type, including no-drill options where possible
Shelf or platform inside the window box
Full-height mesh on balconies, closing gaps at railings and ceiling
Check that windows still open, close and lock safely
Advice on getting landlord or freeholder consent

Who it is for

Flat owners and tenants with no garden of their own
Homes on busy roads where a ground-level catio is not possible
Indoor cats that sit at the window and would benefit from fresh air
Balconies at height where falls are a real risk
Owners wanting a small first step before a larger enclosure

How much does it cost?

As a guide, a fitted cat window box in the UK typically costs £250 to £700, and a balcony mesh enclosure £400 to £1,500, depending on size, height and how difficult the fixing points are. See our full cost guide.

How it works

How cat window boxes and balcony enclosures works, step by step

Measure and check consent

We measure the window or balcony, look at the fixing surfaces and flag where landlord or freeholder consent is needed.

Design for the building

The frame, mesh and fixings are chosen to suit the wall or balcony and to keep the look tidy from outside.

Fit securely

The window box or balcony panels are fixed in place, with mesh tensioned and joins closed.

Check every gap

We check where the frame meets the wall, window or railings, because cats will find any gap they can fit their head through.

Cat window boxes and balcony enclosures: FAQs

Can I have a cat window box in a rented flat or leasehold property?

Usually you need written permission first. Most tenancies say you cannot alter the outside of the building, and most leases reserve the exterior and windows to the freeholder. Asking with a clear design, photos and an explanation of how it fixes and comes off makes approval more likely. Clamp-in or tension-fit designs that do not drill the walls are often easier to agree.

Is a balcony safe for a cat without an enclosure?

Not reliably. Cats can fall when chasing birds or insects, slip off a railing, or misjudge a jump, and falls from height can cause serious injuries. Railings often have gaps a cat can squeeze through. A full-height mesh enclosure is the safest way to let a cat use a balcony.

What size should a cat window box be?

A typical window box is around 60 to 100 centimetres wide, 40 to 60 centimetres deep and 60 to 100 centimetres tall, depending on the window. It should be big enough for the cat to turn around, lie down and sit up comfortably, with a solid top for shelter. Bigger windows can take larger boxes with two levels.

Does a window box need planning permission?

Small window boxes on houses are rarely a planning issue, but flats do not have the same permitted development rights as houses, and listed buildings or conservation areas may need consent for changes to the outside. On blocks of flats, the freeholder's consent is usually the main hurdle.