Question: I recently rented a single story home w/ fireplace. I had a mason inspect the flu who concluded the flu was clean and in good shape. My 1st fire was with a Duraflame log. The smoke clearly entered the chimney without any problems. About 1 and 1/2 hours into the burn the smoke detector went off. No smoke but I could smell fumes from the Duraflame. The house is located in a windy coastal area. The chimney does not have a chimney cap. How would one correct this? Insert a liner? Any help is appreciated. Thanks Answer: It sounds more like a pressure problem in your house to me. As the fire dies down the flue cools off and you have less draft to pull smoke up the chimney. Other devices in your house that exhaust air (dryer, range fan, bathroom fan, furnace, etc.) can sometimes use the chimney as a means of pulling air into the house to provide the makeup air for what they remove. You can have a scenario where two columns of air exist in your chimney - one trying to exhaust the smoke upwards, and one column of cool air dropping down the chimney at the same time. If the cold air overwhelms the chimney then you can get smoke back into the house. Since you don't mention that the chimney smoked when you first lit it, it's less likely that the chimney is too small for the size of the fireplace, as can also be the case. Try not running other devices in the house while you're burning a fire and see if this makes a difference. Next step is to crack a window close to the fireplace to provide more combustion air to see if that helps. I doubt that a cap would solve your problem.