I was talking to a guy recently and he said when he burns wood he has to preheat his flue liner till it starts to draft or his house fills with smoke. He lives out in the country. I'm no chimney expert, but shouldn't draft cold as long as it sits high enough in relation to the roof? He says his brother has the same problem and he lives in town. I don't think the chimneys were built by the same person either. Is this ever normal? what IS normal?