Outdoor Fireplace vs Fire Pit: Size, Footings, Smoke and Code
A fire pit is a low ring on a compacted gravel base that people sit all the way around. An outdoor fireplace is a tall masonry structure on a reinforced concrete footing that throws heat one way and sends smoke up a chimney. Here is how they compare to build and to live with.
The choice between an outdoor fireplace vs fire pit comes down to how people will sit and how much you’re willing to build. A fire pit is a low ring on a few inches of compacted stone that everyone sits around; an outdoor fireplace is a tall masonry structure on a reinforced concrete footing that throws heat forward and sends smoke up a chimney.
Fire pits cost less, seat more and fit a casual yard. Fireplaces block wind, control smoke and give a patio a back wall, but they weigh tons and the footing is a real foundation job.
Quick answer
Fire pit: about 3 to 6 feet across, built on 4 to 6 inches of compacted stone, seats people all the way around, and a wood fire in it up to 3 feet across and 2 feet high falls under the model fire code’s 25-foot rule. Outdoor fireplace: one precast kit stands 8 1/2 feet tall and weighs 7,507 pounds; it needs a steel-reinforced concrete footing, deeper or on piers in frost country, and a mortared kit cures 28 days before the first fire. Your local code and the maker’s manual decide where either one can go.
Outdoor fireplace vs fire pit at a glance
| Fire pit | Outdoor fireplace | |
|---|---|---|
| Seating | All the way around | In front, in an arc |
| Heat | Radiates in every direction | Thrown forward from the firebox |
| Smoke | Goes wherever the wind blows | Drawn up the chimney |
| Typical size | 3 to 6 ft across, about 16 in high | One precast unit: about 5 ft wide, 4 ft 8 in deep, 8 1/2 ft tall |
| Foundation | 4 to 6 in of compacted stone | Steel-reinforced concrete footing |
| Setting it | Hand-laid block or a steel insert | Mortared kit or precast pieces set by machine |
| Fire code (model IFC) | A wood fire up to 3 ft across is a recreational fire: 25 ft | Not a recreational fire; local code and the kit’s clearances |
How each one heats and handles smoke
A fire pit puts everyone at the same distance from the flame, which is why it seats a crowd. It also sends smoke wherever the wind takes it, so on a breezy night someone is always moving a chair.
A fireplace works like the one in your living room. The firebox throws heat out the front, the chimney carries smoke up and away, and the masonry mass blocks wind from behind. The tradeoff is that everyone sits on one side, facing it.
Fireplaces also need more room in front than people expect. The Stone Age 48 kit manual calls for a noncombustible hearth extension 24 inches out in front and 12 inches to each side, and says to keep combustible furniture and pillows at least 4 feet from the opening.
Outdoor fireplace dimensions vs fire pit size
Fire pits
A block fire pit kit is small. Belgard’s square fire pit is 4 feet outside, 2 feet 8 inches inside and 16 inches high, lined with fire brick or a steel insert.
The patio around it is what takes space. Unilock plans at least 6 feet of room on all sides: a 15-foot patio for a 3-foot round pit and four to six chairs, and at least 18 feet for a 6-foot pit. Our patio size guide works through the furniture math, and seat wall dimensions covers a built-in bench around the pit.
Outdoor fireplaces
Fireplaces are big in every direction. The Cambridge fully assembled fireplace measures 4 feet 11 7/8 inches wide, 4 feet 7 7/8 inches deep and 8 feet 5 1/2 inches tall, and weighs 7,507 pounds. Its pieces go in with a machine whose forks can lift 4,000 pounds.
Add the hearth extension and a seating arc in front, and a fireplace claims a deep strip of patio, not a corner. Under a pavilion or porch roof, the Stone Age manual’s 2/10 rule applies: the chimney stands at least 2 feet higher than any roof or projection within 10 feet, and at least 3 feet above the point where it passes through the roof.
The foundation is the biggest difference
What a fire pit sits on
Belgard’s fire pit guidelines call for 4 to 6 inches of compacted aggregate, with the first course set about 4 inches below grade. Depending on the pit’s size and local fire codes, Belgard leaves some space between blocks near grade for air. Line the inside with fire brick or a steel insert, because Belgard says its landscape blocks aren’t fire-rated and can crack under high heat. Building one into a new or existing patio is covered in our guide to a fire pit on pavers.
What an outdoor fireplace sits on
A fireplace needs a true footing. Stone Age says outdoor installations sit on a monolithic pad of steel-reinforced concrete. For its 48-inch kit on stable soil, up to 10 feet tall overall, the minimum footing is:
| Exterior finish | Thickness | Front to back | Width |
|---|---|---|---|
| Thin: fabricated stone, stucco, stain or tile | 8 to 10 in. | 39 in. | 64 in. |
| Thick: full-veneer natural stone or brick | 18 to 24 in. | 45 in. | 70 in. |
With full stone or brick veneer, the minimum footing more than doubles in thickness. Cambridge’s precast unit takes a different route: an excavation 64 by 58 inches and 12 inches deep, about 6 inches of 3/4-inch clean stone compacted every 3 inches, then a rebar-reinforced pad of 4,000 psi concrete cured 48 hours before anything is set on it.
Cold climates change the footing. Stone Age says colder regions may need deeper footings or piers that reach below the frost line to prevent frost heaving, and unstable soil may need the same. Our frost line depth by state guide covers how deep that is where you live. We build in Pennsylvania freeze-thaw country, and a tall masonry box that heaves out of plumb is hard to miss.
How deep is the frost line where you live? Look it up in our frost line depth by state guide, then confirm with your building department.
Don’t set a fireplace on a patio’s sand-set paver base. Stone Age requires a solid, level, noncombustible base such as concrete.
Builder’s note: Mock it up before anything gets ordered. Stake out the fireplace footprint plus the 24-inch hearth extension, stand an 8-foot pole at the back, and set your chairs out at dusk. A fireplace is a wall: you’ll see right away what view it blocks from the kitchen window and whether it shelters you from the usual wind or sits downwind of it.
Fire code and setbacks
For a wood fire in a pit, the 2024 International Fire Code keeps recreational fires 25 feet from structures and combustible material (Section 307.4.2) where your state or town has adopted it. That rule, the 15-foot rule for portable pits and property-line setbacks are covered in our guide to how far a fire pit should be from the house.
A built-in fireplace is treated differently. The code’s definition of a recreational fire excludes fuel contained in an outdoor fireplace, so the model code gives a fireplace no distance of its own. That doesn’t mean it can go anywhere: your town may regulate outdoor fireplaces directly or require a permit for the masonry, and the kit’s own clearances still apply. Ask the building and fire departments before you pour.
Which one fits your yard
Pick a fire pit if:
- You want to seat six or more people facing each other
- The yard is open enough for the 25-foot clearance a wood fire needs
- You want something a handy homeowner can build on a gravel base
Pick an outdoor fireplace if:
- Wind or close neighbors make pit smoke a problem
- You want a back wall for the patio, for privacy or to frame the space
- The site can take a real footing and machine access for setting the pieces
If you’d like to see it drawn first, our fire pit patio plans put the fire feature, seating and setbacks on your lot to scale before anyone digs.
Cooking out there too? See how far a grill should be from the house. Fire pits, hot tubs and pergolas on pavers are all in our pavers and patios guide.
DIY or hire a pro
A block fire pit kit on a compacted base is a fair DIY job. A fireplace usually isn’t: the footing is structural concrete, the pieces are too heavy to lift by hand, and a mortared kit has to go up plumb, level and square layer by layer. Any gas line to either one belongs to a licensed gas fitter.
Frequently Asked Questions
Does an outdoor fireplace need a footing?
Yes. Kit makers call for a steel-reinforced concrete pad; the Stone Age 48 kit’s minimum on stable soil is 8 to 10 inches thick with thin veneers and 18 to 24 inches with full stone. In cold climates or on poor soil, the footing may need to go deeper or onto piers below the frost line.
How big is an outdoor fireplace?
Larger than most people picture. One precast Cambridge unit is about 5 feet wide, 4 feet 8 inches deep and 8 1/2 feet tall, and the Stone Age manual adds a 24-inch hearth extension in front.
How far does an outdoor fireplace need to be from the house?
There’s no single model-code number. The fire code’s 25-foot rule covers recreational fires, which exclude fuel burned in an outdoor fireplace, so your local code and the kit’s listed clearances decide. Check with your building and fire departments before you pour the footing.
How long before you can use a new outdoor fireplace?
Follow the kit’s cure time. Stone Age says to wait at least 28 days after building a mortared kit before the first fire, so moisture can leave the masonry.
Sources: 2024 International Fire Code, Ch. 2 Definitions; 2024 International Fire Code, Ch. 3 General Requirements; Cambridge Pavers, Fully Assembled Outdoor Fireplace Instruction Manual; Stone Age (Stonewood Products), Outdoor Fireplace 48 Installation and Operation Instructions; Belgard Technical Resource Guide, Fire Pit Installation Guidelines (p. 82); Belgard Technical Resource Guide, Square Fire Pit Construction (p. 83); Unilock, Fire Pits: Ideal Patio Size and Design Ideas
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Written and reviewed by Thayne Muthler, owner of Muthler Landscaping & Construction (PA HIC #PA212584). How we check facts: editorial policy.