He installed it yesterday and we let it set for 24 hours before starting it today. We also taped seams to make sure there is no possibility of leakage. He used 4" commercial grade stainless Duravent. Two clean out tees and the better exhaust tip (supposed to shoot the smoke further) which extends about one foot past the cantilever. So far, so good. Wish it had been done this way in the first place. It is quite windy today so we'll have to see how it is when it calms down outside. Now we have to clean inside - apparently, the smoke smell was not just smell - we have some soot in certain areas.