Switching Fuel Types in Your Fireplace can Lead to Spalling of the Flue

Switching from wood burning to gas fuelSome folks enjoy sitting around a hearty, blazing fire in a wood-burning fireplace. Others appreciate the convenience and heat-control offered by a modern gas fireplace. There are a number of differences between the two styles, and because of some of these differences, changing fuel types can lead to expensive and dangerous problems.

We’re going to look at what can happen when a traditional wood-burning fireplace is improperly converted to gas power.


A common problem with this conversion is called “spalling.” Spalling of the flue liner happens when materials such as brick, stone or concrete begin breaking apart.

A key difference between wood and gas fireplaces is the way they affect chimneys. When a wood-burning fireplace is built or installed, the construction of the chimney is designed to operate properly for wood fires. If you’re burning gas fires in a former wood fireplace, gasses produced can lead to the flue lining becoming corroded. Making this doubly dangerous is the fact that it may be quite some time before a homeowner spots any signs of spalling.

A common reason for problems when converting from wood to gas is that the flue in a wood-burning fireplace is too large. When a fire burns, it produces water vapor. An oversized flue isn’t able to allow this vapor to leave the chimney fast enough. This is because the lack of heat makes it difficult to create an efficient draft.

Carbon monoxide: the “silent killer”

Acids are produced when water vapor lingers in the flue lining. This acid, like all other acid compounds, is destructive and can lead to the cracking and crumbling of the flue. When enough debris is present, the draft is impeded, and this can bring about a carbon monoxide hazard.

Many people die every year from carbon monoxide poisoning. Unlike with most other toxic gasses, carbon monoxide can’t be detected by the sense of smell. It’s odorless, and it’s invisible. If a chimney liner has degenerated to the point of creating an obstruction, this deadly gas can seep into a home.

Spalling is just one way a drafting problem can exist. Chimney drafts can also become blocked by debris from outside the home such as twigs, leaves, bird nests and dead small animals. Anything that forms a blockage can be dangerous to all who live in the home.

How to switch fuels safely

Converting to Gas FireplaceEverything we’ve said here doesn’t mean that a conversion from wood to gas can’t be accomplished safely. A lot of it depends on who’s doing the conversion. While installing a gas system is “relatively” simple, a person untrained in this process will overlook flue issues – or not even know they exist. Spalling is almost sure to happen at one point in time if a conversion is made with no thought given to the flue liner and the drafting process.

If you’re tired of the extra work your wood-burning fireplace requires, converting to a gas fireplace might be a great solution. But make sure to have this work performed by certified professionals, who will ensure that the unique venting requirements of a gas-fueled fireplace are met.

Chimney Solutions of Atlanta is standing by with expert technicians who can make your conversion from a wood fireplace to a gas system safe and efficient. Call us at (770) 771-5501.


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