Dogs who are sweet and loving to their families can still be aggressive to other people and animals. These fences aren't usually cheap, so research the options to find the one that's best for your dog.
Picking the Material
Many materials work well as privacy fencing for aggressive dogs. The main point to consider is whether the fence blocks the dog's view; if he can see people and animals outside, it could make him more aggressive, which is known as barrier aggression. Wooden privacy fences make attractive additions to your yard, as do solid vinyl fencing panels and permanent options such as brick or concrete walls. Wood needs replacing more often but is often less expensive than the other options, while making changes or repairs to brick or concrete is expensive and time consuming. Vinyl doesn't offer a natural look, but it stands up well to weather and wear.
Taller Is Better
Shorter fences often cost less, but they might not hold in your pooch. Many dogs can jump or climb fences to escape, so consider your dog's abilities before picking the fence height. A 6-foot-tall fence is fairly standard, although some tall or especially athletic dogs might require an 8-foot-tall fence. Small dogs might be contained with shorter fences such as 4 feet high. Err on the side of too high if there's a question so you don't have to replace or extend the height later.
Building It Right
Wood and vinyl fences require horizontal supports to keep them secure. Even when these supports fall near the top and bottom of the fence, they might give your dog just the edge he needs to get over the fence -- he can use the supports almost like a ladder to help propel him over the top. Make sure these supports rest on the outside of the fence, giving a smooth surface on the inside. The same goes for gates -- keep supports on the outside with the gate securely latched and locked at all times. With other materials, such as brick or concrete, don't put items near the barrier that could help your dog escape, such as benches or large container plants.
Stopping the Digging
Over isn't the only way out. Some aggressive dogs dig under fences to escape and chase their victims. If you have a digger, keep the barrier going at least 6 inches below the ground surface to keep him contained. With a wood or vinyl privacy fence, this could be as simple as a line of chicken wire, a row of bricks or a trench filled with concrete. With brick and concrete, build them so they extend below the surface from the beginning.