Do We Need Outdoor Cat Fences?
The very idea of an outdoor cat fence seems absurd. After all, cats can climb anything, so how can one possibly fence them in? On the other hand, there’s a real need for such fences. Most outdoor areas these days have too many cars, dogs, predators, and poison baits to ensure your cat’s safety. Hence, there’s a real incentive to provide cats with a secure outdoor setting.
Responding to this need, bright people have devised a number of outdoor cat fence types ranging from really reliable to poor. The best ones feature extender arms challenging cats to climb upside down, which they won’t do. Others use modified coyote rollers, multiple rows of plastic spikes, or wide pvc pipes to keep cats in. And still others use the wizardry of radio waves and shock collars as a disciplinary “invisible fence” training cats to stay within a defined border.
Stand-alone Outdoor Cat Fences
The best of all these in terms of reliability are stand-alone cat fences with fencing mounted on vertical posts and inward-pointing extender arms. As noted above, cats, unlike opossums, won’t climb upside down. That means that if the arm is high enough off the ground (6 feet generally does it), reaches far enough in (about 2 feet), and points downward at the end, the system will be reliable and cats will not surmount it.
A variant on this system uses an arm that goes straight in, rather than being angled downward at the end, which creates a temptation for a large, aggressive, and upwardly mobile cat to reach out and grasp the fencing. However, the arm has a clever hinge that can drop the outer part of the fencing downward to thwart the climber. This introduces an element of uncertainty, because what happens if the hinge gets rusted or sticks for some reason? But if all goes as planned (it usually does) this fence is as reliable as any other.
Things don’t end there, because one also needs to gird the nether reaches of the strong polypropylene fencing (the fencing material of choice for outdoor cat fences) against any cats, rabbits, woodchucks, or predators that might be inclined to chew holes. This can be done by applying a 2-foot strip of metal hexagrid or welded wire fencing to the lower portion of the fence and attaching it to the poly fencing with strong zip-ties or hog-ring (circular) staples. Our stand-alone cat fence kits provide all this gear.
Thus girded, an outdoor cat fence will create a safe area that protects cats from just about anything. I say “just about” anything because it does not provide 100 per cent protection against all intruders – such as digging dogs, raccoons and strange cats climbing up the fence from the outside, or winged predators such as large hawks and eagles. But should the need exist, dogs and other diggers can be kept out with digging barriers or low-key electric fences (not radio fences but real electric fences powered by a few flashlight batteries). Such electric fences will also keep out climbers such as racoons and intruder cats, while the very uncommon intrusion of large winged predators can be discouraged by placing appropriate bird netting over the enclosed area. Should you want more information about how to set up these things, send us an email to mcgregor.jal@comcast.net or phone us at 508-888-8305.
Regular Outdoor Fences Converted into Cat Fences
You can also convert a regular fence into an outdoor cat fence. The best way is by adding extender arms and fencing to the existing fence – something that works with fences as low as 3 feet tall—so long as you get cat fence extender arms able to make the modified fence about 6 feet tall.
The fences easiest to convert this way are wooden fences whose heights range from 3 feet upward. Simply affix the extender arm’s base plate to the fence’s posts with wood screws (provided in all our cat fence conversion kits). Then attach the poly fencing to the extender arms with strong black zip-lock ties (also provided in the kits). Secure the bottom of the poly fencing to the top of the wood fence with U-nails or stainless steel construction staples. Make sure that the main body of the wood fence is cat-proof. And close off any openings below the fence with metal hexagrid fencing, hardware cloth, or other suitable materials.
This approach can also be used with metal (chain link and wrought iron) fences, with vinyl fences, and with brick, cinder block, and cement walls. In each case, however, it is necessary to find suitable means of firmly attaching the extender arm’s plate and also for securing the bottom of the poly fencing to the top portion of the existing fence or wall. In many of these cases it would seem reasonable to seek professional advice.
Not all cat fence conversions involve extender arms. Some place rotating cylinders with paddles, plastic strips with spikes, or 5-inch wide pvc pipes along the top of the fence to prevent cats from getting a grip there. However, the system with the rotating paddles is expensive, and the reliability of all these systems is uncertain, depending heavily upon the nature of the existing fence.
Invisible (Shock Collar) Cat Fences
Reliability is also an issue with invisible cat fences used outdoors. These fences (not really fences at all) employ a radio transmitter to define a circular area or send a signal through a buried wire. If a cat wearing a special collar gets too close to the edge of the circle or the buried wire, the collar administers an electric shock or other disciplinary message to the cat.
To me this seems a bit harsh. True, the shock or other signal is harmless—much less physically harmful than the hazards involved in having a cat wear a collar. However, such treatment has been found to induce behavior changes in cats – changes that go beyond simply staying within the defined zone. In view of this, it seems fair to ask whether you as the cat’s owner would be willing to wear a collar, even during relatively brief training sessions, that would administer a periodic shock? If your answer, like most people’s, is a resounding “NO”, then it’s worth asking whether you should be willing to administer such a disciplinary treatment to your pet.
This matter of pet psychology has a bearing on the larger issue of reliability that goes beyond physical problems with the system like severed wires or power outages. That’s because the responses of cats subjected to these strong disciplinary signals varies greatly. Some cats respond by staying inside and refusing to go out, while other more aggressive types get so intent on things like hunting birds or mice that they run right through the system. Neither of these responses is desirable and both are common. So it seems clear that from an owner’s standpoint the reliability of these invisible cat fences is uncertain.
How Affordable Are They?
While not vastly expensive, outdoor cat fences aren’t cheap. The best ones (those with extender arms) have fairly high prices because the extender arms have special hinges or must be custom-made. Ours are more affordable than most. McGregor stand-alone cat fence kits (see our standard cat fence kits) start around $7 per foot, and McGregor cat fence conversion kits (see our economy conversion kits) start around $3 per foot.
Oddly, other less reliable cat fence gear can be costly. Wireless shock-collar fences (not only unreliable but inconvenient because of the necessarily circular perimeter) start out as low as $100, but ones from better-known vendors cost about $260. Wired shock-collar fences fall in this same general price range; but since the wire almost always needs to be installed underground by professionals with special machinery, their installed price is much higher. Rotating cylinders with paddles, besides being unreliable, are quite expensive (never under $11 per foot). Spikey strips for walls cost very little (about $2 per foot) but their reliability is questionable.
What about Visibility?
Aside from the transmitter and shock collar, invisible cat fences are… well, invisible. Spikey strips and rotating cylinders placed atop existing walls and fences (so long as they do not have sharply contrasting colors) also tend to have low visual profiles.
That leaves outdoor cat fences with extender arms. They are clearly visible. However, there are some mitigating circumstances. First, a well-installed stand-alone cat fence with extender arms appears both neat and novel. So a first-time visitor’s impression, rather than “Gosh, that’s ugly.” will tend to be “Gosh, what’s that?”—not a perjorative comment but a conversation starter.
Furthermore, these fences (both the stand-alones and the conversion kits) have black fencing and black posts. Since black is the least obtrusive of all colors (it’s really the absence of color), both the stand-alones and the conversion fences tend to fade from view when seen against a tall landscape or wooded background. So if they can be put in that position, visibility is much less of an issue.
Cat Fence Features

Those who came here to get an outdoor cat fence should be able to get one that meets your needs and is moreover affordable, visually acceptable, and reliable. We offer fences with those features. But as the foregoing suggests, all these terms are relative. Hence, you need to select a few candidate fences that appear to meet your needs and then pick one on the basis of its reliability, appearance, and affordability. We hope this brief overview of cat fence types can help with that.