Mastiff question...?

Is it true that you have to train a Mastiff differently than other dogs? And also my Mastiff is about 2 years old and is not house trained (When he was a puppy my dad got really sick with cancer so he didnt get properly trained) Is there anyway to "Retrain" him...every time i ever let him in its like he gets this uncontrollable urge to crap everywhere...and he is a mastiff so its aaalllooott of crap... And i want to be able to bring him inside but so far he is making it impossible.