Regular chimney sweeping is a critical aspect of chimney maintenance. It improves air flow and increases draft so that smoke can be drawn upward and out of your home. But more importantly, sweeping, by removing the buildup of flammable creosote, reduces the risk of a dangerous chimney fire. There are several things that you, as an engaged and invested homeowner, can do yourself to keep your chimney clean and to minimize blockages and buildup in the first place.
Put a cap on it!
The single most important and easiest thing you can do to prevent blockage of your flue and protect the health of your chimney is to put a cap on it. A chimney cap fits over the top of your flue, typically with a solid top and screened sides, allowing smoke to escape but preventing the entry of snow and rain, plant debris, and most importantly, nesting animals. Available in a variety of materials (stainless steel, copper, galvanized) and for every size of flue, chimney caps are cheap and easy to place (once you're on the roof, that is). There's simply no reason not to take this minimal step in protecting your chimney.
Burn the right type of wood
While we're talking prevention, the wood you're using for fuel definitely matters when it comes to the health of your chimney. Hardwoods (e.g. oak, maple, birch) burn hotter than softwoods (conifers) and thus produce less ash and less chimney-clogging creosote. Additionally, burning wood should be well-seasoned—that is, dried—for at least a year but ideally two or three years. Another best practice for preventing buildup is to keep the fire burning hot and not allowing it to smolder and smoke. Smoke is what turns to creosote and coats the inside of your chimney: the less smoke, the less buildup, the less often cleanings are needed.
Brush the flue
Dedicated DIYers can find various chimney cleaning brushes and tools online. You'll want to find a brush that matches your chimney flue in shape and size—too small and it will just bang around inside without accomplishing much of the scraping that needs to happen for creosote removal; too big and you make your job more laborious and risk damage to the liner or flue, or it could get stuck and break. A chimney can be swept from the roof (top-down method) or from the firebox (bottom-up method), each with its own set of challenges. You'll want to close off the firebox from the living space if you're working from the top down, and if working from the bottom up, prevent debris from entering your home with the help of a powerful vacuum or a plastic sheet placed across the fireplace with a flap for access.
Clean the firebox
After brushing the flue, the creosote chunks and ashes will fall into the firebox. To remove, you can begin with the fireplace broom and dust pan for larger debris, and a dust extractor or shop vac for the finer dust (spare your household vacuum from this dirty job). A cloth moistened with water will also work fine to collect the finer debris and finish the job. Note that the CSIA (Chimney Safety Institute of America) recommends that unless it's the end of the fire season, about an inch of ash should remain in the fireplace, both to protect the bottom of the firebox and to help maintain the next fire.
Where the pros come in
Chimney sweeps have the expertise and specialized tools to effectively remove creosote buildup and any blockages from your chimney flue, and to preventively install or replace a chimney cap. Sometimes creosote levels or blockages are such that removal is best entrusted to a professional. Though creosote buildup in its early stages is powdery and fairly easily removable with appropriate brushing, later-stage creosote resembles a tarry glaze and is far more stubborn, requiring more specialized tools.
Additionally, a chimney sweep's years of experience help them to diagnose and troubleshoot common chimney problems, such as backdrafting or unpleasant odors, and to check various removable parts, such as the damper and cap, to ensure good condition and functionality. They will look for signs of disrepair in the masonry, such as spalling brick or a cracked chimney crown, and recommend repair if necessary. No matter how well or how often your chimney is cleaned, you'll want to have it inspected initially, upon taking ownership of a new home, and then regularly thereafter so that any areas of disrepair can be identified and addressed before they become more significant and costly.
In short, a savvy homeowner will take all necessary preventive measures to maintain the health of their chimney in between cleanings, bringing in a professional regularly to make sure the chimney is free from obstructions and deposits, that it's in good working order, and to check for any signs of disrepair or deterioration.
Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Chimney Cleaning Company.
Many thanks to our technicians Roy S and Ben S for lending their expertise to this article.