Небось дом он отгрохал себе здоровый
He seems to have built a huge house.

Personally I use "небось" very rarely. As well as "вероятно"

Usually it's наверное.

Btw "небось" shifts the probability of an event to even a more positive value than "вероятно" to me. In other words, when you say "небось" you expect that something has happened or it's going to happen or had happened (depending on the tense). When you say "вероятно", "возможно", "наверное", you expect it to happen too but the strength of the expectation is weaker. Also a mocking shade of sense most probably may be implied when "небось" shows up.