House Training the adult IG is not very different from training the puppy. It is easiest if everyone understands that certain rules are to be made when the dog enters the home.
Until the dog can be trusted or if the yard is unfenced, the dog must remain on leash when taken outside.
The dog must go outside (or to the papers or litterbox if the dog is being trained for those) immediately upon the owner rising in the morning. This means that you take the dog to the desired elimination spot before you go to the bathroom, get dressed, brush your teeth or hair. A pair of slip on shoes kept at the back door is ideal for this situation. You tell the dog to do its business (go pee, or hurry up) and since the dog has been rousted from its bed, it will do so promptly. You praise the dog lavishly for being so good, and take it inside for some breakfast. Once it has eaten, you take it outside again to see if it has any more duties to perform. Since you are feeding the dog on a regular schedule, there will be a regularity to the stool, and there shouldn't be any sneak surprises once you have learned the dog's habits.
Throughout the day, the dog is given many opportunities to go outside for elimination. I like to give new dogs an opportunity at least every 2 hours. This is especially critical for adult dogs coming from kennels where they have never had to learn bladder control. As with a puppy, they should be given the opportunity to relieve themselves after vigorous play, eating, drinking and sleeping. Anytime the dog is seen to be circling, sniffing, squatting or lifting a leg it must be hurried outside and told to "go pee". If the dog has already started, simply say "no" or "uh-uh" and take it outside to finish.
What if the dog doesn't relieve itself when presented with the opportunity to do so? Say ,for instance, it is first thing in the morning and the little princess can't bring herself to walk on the dew covered lawn (it happens). She must be confined (you are crate training, right?) Place her in the crate for a half an hour. She may think about it, or she may fall asleep. At any rate, after half an hour take her out for another opportunity. If she avails herself of her chance to pee or poop, she is allowed freedom. If she doesn't, she goes back in the crate. And so it goes through the day. Freedom and praise when she eliminates in the proper place, and confinement if she doesn't go at all. Eventually, you will learn how often they need to go, and the signals they give and you will need to confine less.
What do you do if she eliminates on your rug?! Oh no! Well, you chastise yourself for not watching more closely for the cues (increased activity, circling, sniffing and squatting) and you clean up the mess. Do not use ammonia; it contains urea which is found in urine, and attracts dogs to that spot to urinate again and again. This explains why the dog always pees at the same spot on your walk.
To clean the mess, blot the urine patch with a paper towel or rag thoroughly. Try to remove as much as possible. Mix a little vinegar and water together and pour onto the spot and blot again. This usually works, but some dogs have very strong urine and you may need a commercial product such as "Urine-Erase" or "Nature's Miracle" to remove the odour.
This method of training is easily transferred to any location, be it paper, litter box or shower stall. It is possible to train for a couple of different options which allows more flexibility. If your dog isn't willing to pee outside in a downpour, at least he's trained for papers. If you are visiting relatives and they don't want your dog peeing in their house, at least he can go outside, and on it goes. Overall, the key to successful housetraining is consistency, confinement and patience. It may take some time and hard work, but it is possible to fully train an adult dog within a month or two. However, it must be noted that even then if the weather turns bad, some dogs will find a corner or bathmat to use.