Don't play with fire – use caution in operating that new fireplace

New Construction Corner

Despite advances in heating technology, the humble fireplace remains a feature of many new homes, and with good reason. Nothing is quite as romantic as a roaring fire on a cold winter night.

But operating a fireplace is a responsibility that no one should take lightly. In my years as a home inspector, I’ve seen several house fires and have heard of people succumbing to fumes. New-home buyers should educate themselves about potential fireplace problems and make sure they’re ready to address them.

Woodburning fireplaces arguably require the most caution. Sparks can fly out of the firebox and ignite a combustible surface – your lovely new hardwood floors, for instance. To avoid sparks, always burn dry lumber. Sparks are created when the water in moist lumber turns into steam and explodes. Your hearth should be at least 16 to 20 inches long to catch any sparks that might be created.

Many fireplaces have glass doors to prevent sparks from escaping, but I’m always concerned that those doors also can prevent a fire from getting necessary oxygen. A few fireplaces actually receive oxygen from outside of the building. For others, as oxygen levels deplete within the firebox, carbon monoxide can build up and seep into the room.

A safer solution is to install a grate at the front of the fireplace to bring in outside air. Also, remember to keep the area surrounding the fireplace free from combustibles such as newspapers, books and even toys.

If you’re considering buying a loft condo with a woodburning fireplace, take a close look at the joint where the front wall of the fireplace meets the hearth extension on the floor. That joint must be sealed with refractory cement or special high-temperature caulking, so that sparks won’t fall into the cracks and start a house fire. In my experience, the joints in about 90 percent of manufactured fireplaces are inadequately connected here.

These days, the ventless fireplace is the most common type found in new homes in Chicago, partly because it is inexpensive to install. A ventless fireplace burns natural gas and expels the gas created in this process (a mix of sulfur dioxide, water and carbon dioxide) into the living space, rather than through a chimney or some other external venting duct. Although such fireplaces are legal in Chicago, they are illegal in several states across the U.S because of some of the risks associated with them.

The gases that ventless fireplaces expel into a room can cause allergic reactions in some people. In my years as a home inspector, I have seen people develop skin rashes and nasal or eye irritation after being exposed to the gas created by the ventless fireplace, and many homeowners I know have stopped using their ventless fireplaces for that reason.

It is also possible for ventless fireplaces to deplete oxygen levels, converting air into potentially deadly carbon monoxide. To address the problem, legal ventless fireplaces are equipped with oxygen depletion sensors that, as the name suggests, shut down fires if they detect low oxygen levels.

Examine your fireplace for a stainless steel data tag, which is usually attached to the “leg,” or flame tube, of the fireplace. This data tag should confirm that the fireplace has an oxygen depletion sensor and that it was manufactured in accordance with Gas Appliance Manufacturers’ Association and National Fire Protection Association standards. If the fireplace does not have a data tag or the tag does not indicate the presence of a sensor, it is unsafe to use the fireplace. In my opinion, even if your ventless fireplace does include an oxygen depletion sensor, you should always open a window when operating the fireplace in case the sensor malfunctions.

In my experience, direct vent fireplaces, those that have attached horizontal flues, are the safest type of gas-burning fireplace. But homebuyers should make sure that the external venting duct is at least two or three feet away from all windows and doors.

Homebuyers also should consider the location of their fireplace and whether or not the room has adequate ventilation.

Under federal law and manufacturer standards, any room that contains a fireplace must have 50 cubic feet for every 1,000 BTUs a fireplace creates. If a fireplace provided around 30,000 BTUs, the room containing it would have to be 1,500 cubic feet, or roughly 20 feet by 12 feet, with eight-foot ceiling heights. The fireplace’s data tag should indicate how many BTUs the fireplace provides.

Thomas Corbett is president of Tomacor,, a professional property consulting company specializing in commercial and residential property inspections and expert witness work. Questions can be e-mailed to

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