There's nothing like a fireplace to make your home feel extra cozy when the weather is chilly! Keep your home safe by being on the lookout for these signs that your fireplace may need some maintenance.
Backdrafting
If you find smoke stains above the fireplace, that's a major indicator of a backdrafting problem and means that excess smoke is going into your house rather than up and out the chimney. understand backdrafting we must first understand the basic physics at work in your fireplace.
A Draft is the force pulling air from inside your house up through the chimney. Draft is primarily a result of the difference in temperature between your fireplace and the outside air, as warm air from inside is drawn up the chimney to meet the cold air outside the chimney stack. An implication of this is that it will be more difficult to properly start a fire on a warm day since there won’t be a significant temperature difference to kick-start the draw of the chimney. It also means that when you first use your chimney after it’s been idle for a while, you might have trouble getting the entry to the flue warm enough to get the smoke moving.
If this happens, try holding a lit piece of newspaper or kindling up to the flue entrance right by the damper for a minute or two to quickly warm the flue and establish a draft. This can also be helpful on cold, damp days; humid air is heavier than dry air, so your chimney has to work harder to overcome that resistance.
But if your backdrafting problem is persistent, you need to call a professional to help identify the source of the problem and to make any repairs or modifications necessary to prevent the backdraft.
Creosote
Creosote is a combustible chemical mass of carbon formed when wood, fossil fuels, or tar is burned. Creosote distills and lingers commonly in a fireplace or a masonry chimney. When it is not removed, it can build a thick, hard coating of debris up the flue and chimney, posing a threat to your fireplace.
Creosote comes from unburned fuel that can eventually cause a chimney fire if not periodically removed. Creosote restricts the airflow of your chimney, preventing proper circulation and lowering efficiency. It is a combustible material that is also toxic. You don’t want to be breathing this in, or letting it catch fire.
There are three main types of creosote.
First Degree Creosote is soft and sooty, not really all that different than wood ash.
Second Degree Creosote is kind of like honeycomb toffee only not tasty. It is soft and crumbly and indicates that you may have had a chimney fire.
Third Degree Creosote is a black, glassy, tar-like substance, also called glaze creosote. It requires a special piece of equipment with rotating chains to remove.
Depending on how well maintained your fireplace is and whether or not you’ve had it professionally inspected recently, you can always attempt a DIY Fireplace cleaning. But it’s hard work, potentially dangerous and can be extremely messy if done improperly and we do recommend leaving it to the professionals.
Cracks
Cracks and deteriorated mortar joints are dangerous fire hazards. Any visible crack should be sealed - for tiny hairline cracks, there are caulk tube repair sealants specifically for chimney fireboxes. You will find that most Chimney Sweeps do this sort of repair, as do Chimney Masons. Be sure the repair includes inspection for additional unnoticed cracks - in the firebox or elsewhere on the chimney, because this may or may not be an indication of more extensive problems. Very commonly just an aging thing or erosion of the mortar due to heating and cooling, but you never know till you inspect.
A fireplace is usually built with several layers of fire protection, but one crack can bypass all of the protective measures and start a house fire.
Efflorescence
To end on a lighter note - If you notice any white streaks / white crystalline deposits in your firebox, don’t fret. White deposits on the interior of the fireplace aren’t safety hazards and don’t necessarily represent an immediate threat. But they’re not just ugly stains. Efflorescence indicates that there is moisture penetration which eventually will cause your fireplace to deteriorate over the course of a few decades. If you notice these streaks make a note and bring it up with a fireplace inspector next time you have one over.
