Remodeling work puts on a damper on fireplace use

Q: For several years, we have not been able to enjoy a cheery fire on a cold day. About eight years ago, we enclosed our back porch and made it into a TV room. What used to be the outside of the chimney is now on the inside wall of the TV room. When we enclosed the porch, we knew we needed fresh air for the fireplace, so a 4-inch flexible pipe was routed about 10 feet to access outside air. When a fire is first lit, there is a lot of flame and updraft. Then the fire burns down and the updraft decreases to the point where we get some smoke in the living room, which irritates our eyes and even sets off the smoke alarm. We miss our fireplace. Any suggestions?

A: Now that the chimney is inside the home, it should be warmer and should draft better than a cold chimney that is exposed to the environment. Draft problems are generally associated with flue height. Rule No. 1: The chimney needs to be a minimum of 3 feet above the roof. This rule applies to chimneys that protrude through the ridge of the roof or for chimneys on the gabled ends of a home. Rule No. 2: The flue must extend at least 2 feet above any obstruction that is within 10 feet of the chimney. The 2-in-10 rule applies to chimneys that are next to a hip roof, at the eave of a gabled roof or where a chimney is located near a second-story wall on a multilevel home.

I would imagine the new roof for the TV room is too close to the top of the flue. Any air movement near the roof and chimney will cause the flue to backdraft when the warm fires die down. One repair I have suggested in the past is to simply add an extension to the flue. If the flue extension is too long and is an eyesore, the entire chimney can be extended. Costs may be the only thing to keep you from enjoying the fireplace this winter.

Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home-improvement questions at d.Barnett@insightbb.com. Sorry, no personal replies.