Q: I plan to use my fireplace more to lower my utility bills. I see some deteriorated spots on the outside of the chimney, and it has not been cleaned recently. What type of maintenance items can I do myself?
A: Before doing any chimney maintenance yourself, have a professional chimney sweep inspect and clean it before you build your first fire. House fires due to chimney issues occur in tens of thousands of homes each year, claiming many lives and costing hundreds of millions of dollars.
Although the deteriorated spots on the brick chimney need to be addressed, problems inside the chimney present the greatest risk. Creosote buildup is the primary problem — it is very flammable when it gets hot.
When creosote catches fire inside the chimney, it is not always obvious. One telltale sign is a sudden increase in the draft up the chimney from the intense heat, but this still can be easy to miss.
The metal flashing between the roof and
chimney should have a water-tight seal. If the
flashing is badly rusted, replace it.
The intense heat may cause the tiles — which protect the chimney — to crack and come loose. This allows heat from fires to penetrate the brick and start a fire in your home. Sometimes loose tiles will block the chimney, and the smoke drafting back indoors will alert you.
When the professional cleans the chimney, puffed black creosote may mean there was a chimney fire. Once it is cleaned, an inspection along the chimney’s entire length with a camera should be done to check the tiles and mortar.
Be leery of a chimney sweep or company that does not do the camera inspection and claims you need a new liner or sealing procedure costing thousands of dollars. An unscrupulous chimney professional claimed my chimney needed a liner, but a subsequent camera inspection by a different company indicated the tiles and mortar were sound.
For those who are handy and not afraid of heights or do-it-yourself projects, products are available to make many chimney repairs. Companies — such as SaverSystems — carry supplies for professionals and offer their products in smaller quantities for homeowners to buy.
Although brick feels very hard, it is permeable to water. Over time, moisture can deteriorate the mortar. This is particularly bad 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 elastomer to fill the spots. Afterward, coat the entire chimney exterior with a water repellent formulated for brick.
Check your chimney crown for loose parts
needing repair.
If the mortar is bad, the chimney crown likely needs some repairs. Chip away any loose cement and fill in the pits with an elastomer crown repair. Some types are formulated specifically to cure in freezing temperatures.
The metal flashing between the roof and chimney is the final area to seal. If the flashing is badly rusted, replace it. Most often, brushing on a thick coating of flexible flashing compound is an adequate fix.
Whether you hire a professional to make repairs or do some of them yourself, check your chimney before the first fire of the winter season.
CORRECTION;
September’s Ask the Energy Expert featured links to find information about tax credits for energy efficiency improvements. We published an incorrect URL. The correct web address is energyoffice.colorado.gov/hptc.