House-training an adult dog requires crate-training and plenty of positive reinforcement for desired behavior. Prevent an adult dog from having accidents in the house with information from a certified dog behaviorist in this free video on dog breeds.
Let's talk about how to house train the older dog. Older dogs that are not house trained have actually been reinforcing the wrong way and the wrong place to go so we have to sort of change this association. Again, we use a crate for a dog of any age that is not yet properly house trained. When house training an older dog, we use the same techniques we would with a younger dog. Okay, it's important that the dog is comfortable in his crate and that we have lots and lots of intervals where we go out with our dog, on a leash, to the area where we do want him to eliminate, wait 'til he does, and praise him vigorously. Again, the proper size of the crate is very important, and if in fact your dog is comfortable in his crate and will not soil in that, 'til we have house training down to the level where it's acceptable, lots of crate time is good for an older dog who still hasn't mastered house training in your home. Again, the concept of house training has to do with the fact that a dog will usually, and generally not soil where he sleeps, so proper size of your crate is very important. If in fact you have a smaller dog that you expect to grow larger, make sure you put some spacers in that crate so your dog can't eliminate in one area and then sleep twenty-four inches away in another.