Outdoor Fireplaces and Fire Pits

Four kinds of outdoor fire

Most backyard fires fall into four groups. They differ less in how cozy they feel than in where the smoke goes and what has to be maintained.

• Open fire pits and rings. A steel ring, a stone ring or a dug pit. Smoke leaves at ground level and drifts wherever the wind sends it. There is little to maintain beyond the ring itself and the ground around it.
• Portable fire bowls, chimineas and spark-screened units. Sold as freestanding products, usually steel, cast iron or clay. Some have a short stack that lifts the smoke a few feet. The maker's instructions set where and how they may be used.
• Built outdoor fireplaces. Masonry or stone structures with a firebox, a smoke chamber and a chimney. They behave much like an indoor fireplace and age like a chimney that is exposed on every side.
• Gas fire pits and tables. A burner fed by natural gas or propane, often in a stone or metal surround. No wood smoke and no ashes, but the gas supply and burner have their own requirements.

Tabletop firepots that burn pourable gel fuel are a separate category. A joint warning from the National Fire Protection Association and the U.S. Consumer Product Safety Commission describes a serious risk of flash fire and burns when gel is added to a pot that is still burning or still hot, and notes that burning gel sticks to skin.

Start with what is allowed on your lot

In New Jersey, more than one authority can have a say in a backyard fire, so the rules come before the shopping.

• The New Jersey Forest Fire Service. Its recreational fire permit page says that before having any fire within a forested area, you must contact the nearest Forest Fire Service office to request a permit. The permits are free, and the page asks for requests at least 10 days ahead.
• Your local fire official. The same page notes that you may also need a permit from the local fire official or the NJ Division of Fire Safety, and that open burning has to follow the state fire code as they enforce it.
• Your town's ordinance. The U.S. EPA notes that some local governments restrict backyard recreational fires and suggests checking with local authorities. Some New Jersey towns publish their own distances, permit types and size limits.

Conditions can also change during the year. The Forest Fire Service uses stages of restriction in wooded areas: at Stage 1, fires directly on the ground are prohibited; at Stage 2, only elevated prepared fireplaces, elevated charcoal grills, or stoves using electricity or liquid or gas fuel are allowed; at Stage 3, only electricity or liquid or gas fuel. A wood-burning fire pit that is fine in October may not be allowed during a dry spring.

A short decision path

Working through these questions in order usually narrows the choice quickly.

1. Is the yard in or next to woods?If yes, call the Forest Fire Service and your fire official before buying anything wood-burning. If restrictions are common where you live, a gas unit may be the only type you can use during dry periods. If not, go to step 2.
2. How far can it sit from the house?Measure from the spot you have in mind to the house, deck, fence, shed and overhanging branches. If the distance your town requires does not fit, a wood fire is out and gas or nothing is left. If it fits, go to step 3.
3. How close are the neighbors' windows?Ground-level smoke from an open pit drifts into nearby yards. If houses are close, consider a unit that lifts the smoke, a built fireplace with a chimney, or gas. Otherwise go to step 4.
4. How much upkeep do you want?A ring or portable bowl needs little. A built fireplace adds a chimney, a crown and a cap to look after. A gas unit adds a burner and a fuel supply that need servicing by a qualified gas professional.

Placing it: distance, overhead and underfoot

The U.S. Fire Administration advises keeping a fire pit at least three feet away from your house and anything that can burn. Treat that as a floor. Local rules can be stricter. As one example, the Borough of Somerville's fire prevention page lists 25 feet from a structure or combustible material for a recreational fire that is not in an approved container, 15 feet when it is, and 15 feet for portable outdoor fireplaces. Your own town's numbers may differ, so ask before you build.

Distance is only one direction. Look up for branches, eaves, awnings, umbrellas and string lights. Look down at what the fire will sit on: a wood or composite deck, dry mulch and lawn can all be ignited by heat or a dropped ember. For a portable unit, the manufacturer's instructions say what surface and clearances it needs, and they are worth reading before the first fire.

Plan where people will be, too. USFA advises closely watching children while a fire pit is in use and keeping matches and lighters out of their sight and reach. A clear path around the fire, with chairs set back from the edge, keeps anyone from stumbling into it.

Smoke, wood and the neighbors

The EPA notes that outdoor recreational fires can become a considerable source of fine-particle air pollution. The amount of smoke depends mostly on the wood and on the weather.

• Burn dry wood only. EPA's backyard fire tips call for seasoned, dry wood, checked with a moisture meter, with about 20 percent moisture as the target. Our firewood guide covers testing and drying, and buying firewood in New Jersey covers the purchase.
• Keep everything else out. EPA says never to burn green wood, construction waste, plastic, garbage or yard waste in a backyard fire, because they create more smoke and can be toxic. A fire pit is not a place to get rid of leaves or old lumber.
• Watch the wind and the air quality. EPA asks people to consider their neighbors and the wind direction, and never to burn on air quality alert days.

A spark screen over a wood fire, which USFA recommends, also keeps embers from drifting toward a neighbor's yard or roof.

A built outdoor fireplace is still a chimney

Once an outdoor fireplace has a firebox, a flue and a chimney, it has the same parts as an indoor one and many of the same weak points. The difference is exposure. An indoor chimney is warm on the inside and protected by the house below the roof. An outdoor one takes rain, freezing and sun on every face, from the hearth to the top.

• The top. A crown that sheds water and a cap with a screen keep rain, animals and embers in check. See crown vs. cap and cap types compared.
• The masonry. Water that soaks into brick and joints and then freezes is what breaks masonry down. Flaking faces and crumbling joints are covered in why chimney brick flakes and crumbling mortar joints.
• The draft. Short outdoor chimneys and open patios with crosswinds can struggle to pull smoke up. The reasons are the same ones described in why a fireplace won't draw.
• The flue. Creosote forms in an outdoor flue the same way it does indoors, so a fireplace used often needs its flue checked and swept.

If you are planning a new one, ask the designer or builder how the flue, the firebox lining and the top of the chimney will be detailed, and confirm what your town's construction office requires for the structure.

Gas units and conversions

The EPA notes that switching to natural gas or propane reduces harmful air pollutants, and that kits to convert existing fire rings and pits to gas burners are sold at hearth and patio stores. A gas unit also removes the ash and ember questions.

It brings its own. The burner has to be installed according to its manufacturer's instructions, and a natural gas line to the yard is a job for a qualified gas professional working under your town's permit rules. Propane tanks have their own storage and connection instructions from the supplier. Gas does not get around every restriction. The Forest Fire Service's Stage 3 still allows liquid or gas fuel in wooded areas, and your town may set limits of its own.

Putting it out and walking away

The Forest Fire Service page cites a New Jersey statute that prohibits leaving a fire that could endanger property without a careful and competent watch. USFA puts the household version simply: turn off or put out fires before you leave the backyard.

• Keep water or a hose, or a bucket of sand, within reach before you light the fire.
• Let the fire burn down, then drown the coals and stir until nothing hisses or glows.
• Feel for heat with the back of your hand held above the ashes, not on them.
• Treat the ashes as live for days afterward. The steps in getting rid of ashes safely apply outdoors too.

A built outdoor fireplace with a damper should have the damper left open until the ashes are cold, for the same reasons as indoors.

Questions homeowners ask

Sources

1. NJDEP, New Jersey Forest Fire Service: Recreational fire permits
2. U.S. EPA Burn Wise: Backyard recreational fires
3. U.S. Fire Administration: Outdoor fire safety (PDF)
4. Borough of Somerville, NJ: Bonfires, recreational fires and outdoor fireplaces
5. NFPA and CPSC: Pourable gel fuel warning (PDF, hosted by the State of Michigan)

This guide is general information. It can't diagnose a specific chimney; an inspection can.