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Extending your cat's indoor environment with a fully enclosed secure outdoor area is a great way to give your cat a complex and interesting environment with lots of choice as well as helping to keep them safe. This option fully encloses an outdoor space for your cat such as an area of your garden, balcony, courtyard, or patio by using a barrier such as net, wire, or solid material to secure all the potential exit points (to the sides and, potentially, overhead).

Example of a garden cat enclosure (made using wire and wood) that is attached to the house and contains platforms and walkways.

Example of an enclosed patio cat enclosure (using netting) that is attached to the house and contains cat towers, multiple levels, and places to observe, rest, sleep, and hide.

Make sure the enclosure is both escape-proof (to stop your cat getting out) and animal-proof (to prevent other animals getting in). The enclosure should be attached to your cat’s indoor space via a cat flap (or a window or door that can be left open), so that your cat has free and immediate access in and out of the indoor/outdoor spaces.

Having your cat’s outdoor space linked to the indoors is important as it means your cat can choose where they spend their time. They can retreat into the house if something outside scares them, and there is less risk of accidental escape than if you are moving them into a separate enclosure. If you have a balcony or veranda which can be made escape-proof, this is another option. 

To avoid your cat dashing through a door or gate and escaping, it can be helpful to create a double door or gate system at the external exit point(s) to your cat's outdoor area. This means that at the exit point you open one gate (or door), enter this space, then close the first gate and check to make sure your cat has not come through before opening the next gate. See example below:

If your only option is to have a freestanding enclosure, it is strongly recommended that this is connected to the house. You can do this with by connecting the freestanding enclosure to the house (or a part of the house) with a tunnel and cat flap for safety, social connection, and welfare considerations. That way the cat can choose to be inside or in their enclosure whenever they want and wherever they feel safest, happiest, and most comfortable.

A freestanding enclosure that is not connected to the house is not recommended as this option does not give your cat choice about when to use the enclosure or be inside, and there are also potential safety and comfort related issues with this option. For example, it can be difficult to provide an environment that can be kept at a comfortable temperature in a freestanding enclosure. Ensuring that it does not get too hot or cold is an important consideration as the cat will not have the choice to move to another area to help regulate their temperature. 

Extending your cat's indoor environment with an outdoor space in your yard or garden that is surrounded by an escape-proof and animal-proof barrier will help to keep your cat safe and give them a complex and interesting environment with lots of choice. 

There are plenty of ideas and products available to help you make your yard or garden escape-proof, such as a modified fence or netting.

For more information see the Cat-proofing tips section below.

Enclosed garden secured using existing fencing with rollers on the top (connected to the indoors via a cat flap for free access).

This can work well when you provide for all your cat's needs within your home. That means providing enough space, and lots of mental and physical enrichment for your cat - including consistent, predictable, and positive interactions with people - and multiple and separated areas for eating, drinking, sleeping, hiding, toileting, scratching, and playing.

To help your indoor cat benefit from exposure to outdoor sights, smells, and sounds, you can install cat-proof screens so that windows and doors can be opened without your cat escaping.

Cat-proofing a backyard with cat-proof fencing

The photo above/right shows an example of a garden enclosed with rollers on the top of existing fencing to make it cat proof.

If you have an existing continuous solid fence around your backyard, you can modify the top of the fence to stop your cat gaining purchase and climbing over to escape. You can achieve this using rolling cylinders, smooth metal or plastic sheeting, or inward-inclined wire. Please note that inward-inclined wire or smooth sheeting just on the inside of your fence will not prevent other cats coming into your garden. To stop this, you will need to install rolling cylinders, or use inclined wire or smooth sheeting on both sides of the fence. 

Alternatively, you can erect a new solid fence with an escape-proof top to create a secure space. 

A cat-proof fence should have a total height (including any extension/escape-proof top) of at least two metres, or your cat may jump over it. 

Don’t forget to check for anything that might lead to an escape, such as gaps in the fence, around gates, where the fence meets the building or overhanging trees and tree trunks near the property boundary. Check the escape-proofing regularly to make sure that it remains safe and secure. 

If you have any trees close to the fence, a simple way to stop cats climbing them is to fix a smooth metal or plastic band around the trunk at least two metres off the ground. 

Using netting for cat proofing

Cat-proof netting can be used to provide a secure outdoor space in a backyard, balcony, courtyard, or patio. The netting should be floppy (but not stretchy) to discourage climbing. To avoid your cat getting their paws, claws, or even their head caught in the net, the openings should be about 50mm wide. Young kittens should be kept away from netting until they are close to adult size. 

If a net extension is being added to an existing fence, the total height needs to be at least two metres, or your cat may jump over it. 

Example of a netting extension to an existing fence to make a cat-proof safe enclosed outdoor space.

Keep the net in good condition by reinforcing it along attachment points and making sure it can’t be chewed. Check it regularly to make sure that it remains safe and secure. 

Other considerations for cats with secure outdoor spaces

Note that a cat contained in a backyard or enclosure may still kill or injure wildlife if they enter the cat’s space. You can reduce this risk by fitting an effective and humane predation deterrent collar with quick release on your cat (for an example, see image and details below) and making sure the enclosed area does not contain plants, food, or water sources that would attract wildlife.

Willson SK, Okunlola IA, Novak JA (2015) Birds be safe: Can a novel cat collar reduce avian mortality by domestic cats (Felis catus)? Glob Ecol Conserv. https://doi.org/10.1016/j.gecco.2015.01.004

In addition, you still need to be aware of and take steps to reduce risks that your cat might face even in a cat-proofed garden or enclosure, such as snakes, ticks, other predators, and ill-intentioned people.

Cat proofing a balcony, courtyard, veranda, or patio

Cat-proof netting (or wire) can be used to provide a secure outdoor space in a balcony, courtyard, veranda, or patio. Just ensure that any exit points are cat-proofed – this includes any gaps between the balcony fence and the house (such as between rails, between the fence and the walls, and between the fence and the roof). 

You can also enclose a small backyard or courtyard by covering the top (fence to fence/wall to wall) with netting/wire or extending your fence height with netting/wire. Netting should be floppy (but not stretchy) to discourage climbing. In the case of enclosing a balcony or veranda, rigid netting or wire can be used if the top of the balcony or veranda is cat-proofed or fully enclosed (e.g., with the roof). 

Creating an optimal environment for your cat in their outdoor space (e.g., (enclosure/enclosed garden) is just as important as for their indoor environment.

As well as being safe and secure, it is important that their outdoor space also feels safe and secure to your cat. Also, the more appealing the outdoor space is, the more like your cat is to enjoy it and want to use it.

You can use the five pillars of a healthy feline environment explained below to create an outdoor environment that meets your cat's mental and physical needs and enriches their life.

For example, you can create an outdoor space for your cat that:

• Is a safe place (i.e., it is safe and secure and feels safe and secure with resting and hiding places, a variety of elevated platforms at different heights, and adequate protection from the weather [e.g., sun, rain, wind] and extremes of heat and cold).
• Contains multiple and separated key environmental resources (e.g., drinking stations, places to scratch, opportunities to play, and areas to sleep and rest).
• Provides opportunity for play and predatory behaviour (e.g., provide toys and play time outdoors as well as indoors).
• Facilitates positive, consistent, and predictable human-cat social interaction (e.g., spend quality time allowing your cat to interact with you in ways they enjoy in their outdoor space).
• Is an environment that respects the importance of the cat’s sense of smell and other senses (e.g., consider the impacts of the outdoor environment on your cat’s senses [smell, sight, hearing, touch, and taste] and try to avoid or minimise negative impacts [such as the sight of unfamiliar animals and people, which your cat may find scary] and maximise positive impacts [such as cat safe plants with enjoyable scents].

It is also important to provide as many options as possible within the enclosure to help your cat regulate their temperature. For example, hiding places that that are warm and cosy (such as a box with warm bedding) and hiding places that will be cooler (like shady spots under cat-friendly plants).

If you have more than one cat, if they are part of the same social group, they should be able to socialise and co-exist peacefully with each other. However, putting two or more cats who are not in the same social group into close proximity in an enclosed space with few options to create or maintain distance between them can cause significant stress, and even possibly lead to physical conflict.  For more information on feline social groups and special considerations for multi-cat households, read on!

Feline social groups

If you have more than one cat living with you, each individual cat may either behave as a solitary cat or be part of a social group of cats. There may be more than one social group within the household. For example, if you have three cats, you may have one social group that consists of two cats and one cat who lives as a separate social entity, all within the same household.  

When you have more than one cat in your family, social acceptance between the cats is not guaranteed, even if they are together from the beginning. Particularly when adding a new cat to a family with an existing cat (or cats), the new cat must be viewed and treated as a separate social entity/group from the existing cat(s), at least initially, although that may change if the existing cat(s) accept the new cat into their social group. 

In multi-cat households, a lack of understanding of the number and make-up of the feline social groups and a failure to design the environment to accommodate these can result in cats not being able to easily access their essential resources, which can cause them stress, fear, anxiety, and frustration. Cats may block another cat’s access to resources (e.g., litter tray, cat flap, resting, or perching place), especially if they are unhappy about the other cat and their activities.  

There are a number of clues that can help you understand the cat social groups in your household. Cats who are part of the same social group tend to display certain behaviours towards the other cats in their group, including allorubbing (rubbing their faces and bodies against the other cat), resting or sleeping in close proximity to the other cat, playing together, grooming each other (allogrooming), and tail wrapping. Cats not in the same social group do not show these behaviours towards each other.  

It is important to understand the make-up of your feline household as you need to provide adequate physical separation of resources so there is no need for the cats to share the same areas to access the resources. Even within the same social group, each individual cat still needs their own resources within their social group’s area (e.g., litter trays and scratching posts). Ideally, and definitely if cats in the household are showing signs of stress or conflict, each social group should have a core territory of their own that is safe and secure, which cats from the other social groups cannot access.  

The cats in the images to the right are showing behaviours indicating that they are part of the same social group (allorubbing, allogrooming, tail wrapping, and sleeping together).

Special considerations for multi-cat households

If you are wanting to have more than one feline family member, consider adopting two kittens who are littermates or adopting two cats together who are already bonded and get along well (these kitten/cat combinations may be more likely to get along and live happily together compared to kittens/cats who are not littermates or bonded cats).  

Consider whether you can provide an environment that meets the physical and mental needs of more than one cat, as each cat needs multiple and separated resources immediately available to them at all times (e.g., food, water, toileting areas, scratching areas, play areas, and resting or sleeping areas). 

If you do bring more than one feline into your life, make sure they are introduced in a way that maximises the chance of a successful and happy multi-cat home; but keep in mind that a harmonious multi-cat household is not guaranteed. All cats are individuals, and some love the company of other cats, but many others prefer to be on their own.  

Having other cats living in the same space is often a significant cause of stress for cats. The impact of this can be minimised by providing each of them with multiple and separated essential resources, but there may still be tension between cats, and this can contribute to poor mental and physical wellbeing and unwanted behaviours like inappropriate toileting/spraying. 

Another component of the feline home environment that is important to consider is whether all the cats in the household can access all the areas of their territory without being blocked by another cat. Having multiple entry and exit points to different areas can help minimise stress caused by cats blocking access to other cats. Although the design of a house with hallways, staircases, and doors makes it common to have only one entry/exit point, if this is an issue that is contributing to stress in a multi-cat household, it might be possible to overcome these issues by using the three-dimensional space of the house (e.g., with shelving to provide a ‘high road’ as well as the floor for a ‘low road’ or creating ‘hatches’ between rooms to act as an additional entry/exit point in addition to the door). If you have multiple cats and they have an outdoor area, making sure they have multiple entry and exit points to this is also important as cats can block another cat from using the cat flap if there is only one.  

Understanding the feline social groups in your household will help you to better monitor for any subtle signs of conflict and adjust the environment to better support the wellbeing of the cats in your life.

Intercat tension

If you have more than one cat, it is important to be aware of signs of intercat tension and monitor carefully for these signs. The complexity of cat relationships and the potential for long term damage to these relationships and significant negative impacts from intercat tension on the wellbeing of all cats in the household mean that taking appropriate preventative steps (including providing an environment that meets the needs of all cats in the household), prompt recognition of intercat tension, and early and effective management are vital. 

There are many situations that can trigger intercat tension, even if the cats have previously got along well. These include the addition of a new cat to the home, a change in home or family dynamic (e.g., moving house, redecoration/refurbishment of the home or a change in human or animal family members, including the death of a family member), other neighbourhood/outdoor cats in the vicinity (even if they cannot directly interact with your cats but your cats can see/smell/hear them), one or more cats with medical issues or pain, and veterinary visits. So, it is important to continually monitor your cats' interactions and behaviour and be aware of signs that might indicate tension.

Signs of intercat tension include (some signs can be quite subtle and easily missed or misinterpreted):

• Staring 
• Chasing
• Stalking
• Fleeing
• Tail twitching
• Hissing
• Wailing or screaming
• Blocking
• Hiding
• Growling
• Biting
• Chasing
• Spitting
• Swiping
• Direct physical conflict (note that tufts of cat hair around the home can indicate that cats have had a physical conflict that people did not see).

When there is tension between cats, they may avoid one another but when this avoidance affects the ability or one or more cats to engage in important normal behaviours (like using the litter tray, eating, drinking, scratching, playing, interacting with people), this can be a problem even in the absence of overt signs of conflict.

For more information on intercat tension, including its recognition, prevention, and management please see the 2024 AAFP Intercat tension guidelines. These guidelines have a lot of helpful information, including photos and links to videos on how to recognise cat behaviour and body language indicative of intercat tension (and harmonious relationships) and how to differentiate physical conflict from play behaviours which can look quite similar sometimes.

If you think that your cats are displaying signs of intercat tension, please seek veterinary advice to discuss the situation, assess for medical conditions and pain, and make and implement a plan to help your cats.