Making your chimney safe
If your chimney has not been cleaned recently, have a professional chimney sweep clean and inspect it before using the fireplace. Problems inside of the chimney are the greatest risk. Creosote buildup is the primary problem, becoming flammable when it gets hot.
When creosote catches on fire inside the chimney, it is not always obvious from indoors. One telltale sign is a sudden increase in the draft up the chimney from the intense heat, but this still is easy to miss.
The intense heat may cause the tiles that protect the chimney to crack and come loose, allowing heat to penetrate the brick and start your house on fire. If you are lucky, the loose tiles will block the chimney and the smoke backdrafting indoors will alert you.
DIY
If you are handy and not afraid of heights, do-it-yourself products can make many repairs.
Start with the chimney brick: Brick feels hard but it is permeable to water. Over time, moisture can deteriorate the mortar, especially in climates with freeze/thaw cycles over winter.
Inspect all the bad spots on the mortar using a chisel and hammer. Remove all the loose mortar. Use cement-colored elastomers to fill the spots. Coat the entire chimney exterior with a liquid water repellent afterward.
If the mortar is bad, the chimney crown likely needs some repairs. Chip away any loose cement and fill in the pits with an elastomers crown repair. Some types are formulated specifically to cure in freezing temperatures.
Finally, seal the metal flashing between the roof and chimney. If it is badly rusted, replace it with new flashing. Most often, brushing on a thick coating of flexible flashing compound is an adequate fix.
CHIMNEY CAUTIONS
Once a chimney is cleaned, the sweep should do a visual inspection along its entire length with a camera to check the tiles and mortar. Be leery of a chimney sweep who does not do a camera inspection and claims you need a new liner or sealing procedure costing thousands of dollars.
JAMES DULLEY is a nationally syndicated columnist who writes on energy efficiency and do-it-yourself energy topics.
