Housebreaking an adult or older dog is essentially the same as housebreaking a puppy, with the only real difference being that a normal adult dog is physically capable of holding its urine and feces longer than a puppy. Housebreaking requires the proper use of a dog crate.
A dog crate mimics a dog's natural desire to feel safe and secure in a small enclosed space that is similar to a den if the dog were in the wild. As dogs learn by association, it is the most effective tool to teach a dog that the only acceptable place to relieve itself is outdoors by taking it out of the crate at suitable times and directly outside to do so.
Utilizing a dog crate of the proper size keeps the dog from relieving itself while in the dog crate, as it takes advantage of a dog's natural desire to not soil its immediate space. Dogs normally need to relieve themselves after waking up following a night's sleep, after exercise, and about 15 minutes after eating a meal, so effectively timing when the dog is removed from the crate and taken outdoors teaches it quickly to not relieve itself in the house.