Outdoor Fireplace Kit or Built on Site

What Comes in a Kit

Outdoor fireplace kits come in two very different kinds. A factory-built kit is a tested appliance: Unilock describes pre-built outdoor fireplaces as coming with a factory-made stainless steel firebox, pipe and metal termination cap, and one outdoor wood-burning model of that type is listed to UL 127 and comes with a manual covering every clearance and the chimney height.

A modular masonry kit is a set of precast or block pieces that stack into a fireplace shape. It saves design work, but the result is a masonry fireplace, and the masonry rules still apply to it.

What a Fireplace Built on Site Has to Get Right

A site-built masonry fireplace is designed to the 2023 Florida Building Code, Residential, chapter 10. The parts that decide whether it lasts and draws:

• A firebox at least 20 inches deep, with the throat at least 8 inches above the opening (R1001.6 and R1001.7).
• A fire brick lining at least 2 inches thick in refractory mortar, or 10 inches of solid masonry (R1001.5).
• A flue at least a tenth of the opening's area for a square liner (R1003.15).
• A footing at least 12 inches thick, 6 inches wider than the fireplace on every side (R1001.2).

Footing and Base, Either Way

Neither kind sits safely on pavers. A masonry kit weighs as much as any masonry fireplace and needs the same footing. A factory-built unit is lighter, but the chase, stone and hearth built around it are not, and its manual adds a non-combustible platform sloped away from the house with a drain where water can collect. Our guide to outdoor fireplace footings has the numbers.

Which One Fits Your Project

The choice usually comes down to how standard the design is.

• A standard size against a wall or in a corner, built quickly, favors a factory-built kit with its listed chimney and cap.
• A custom size, a wide opening or a fireplace built into an outdoor kitchen favors a site-built masonry fireplace.
• A tight spot near the house favors a factory-built unit, whose manual gives exact clearances.
• A matching stone or brick finish works with either, since both are wrapped in a chase.
• A DIY build favors a modular kit or a factory-built unit, with the manual followed to the letter.

Where DIY Kits Go Wrong

The instructions are where a kit build succeeds or fails. The factory-built outdoor fireplace manual warns that the termination cap must overlap the chimney pipe by the specified amount, or the chimney can separate from the cap and let sparks, heat and embers escape, and that only parts listed for the unit may be used. That manual says any variance from its instructions is not covered, and one oven maker says the same of its warranty.

Gas is the other common mistake. A fire pit kit maker says natural gas connections belong with a professional, and Florida code section G2453.1 has a permanently fixed outdoor gas fire feature tested to ANSI Z21.97 and installed to its maker's instructions.

Getting It Built Right

Whether you choose a kit or a site-built fireplace, the footing, the clearances and the chimney height are the same conversation, and it is the one we have on an outdoor fireplace installation visit. The free inspection comes with a written estimate for either route, from experienced builders at a local, family-owned firm.

We are Proudly American and fair about advice, and a Proudly American crew will tell you honestly when a kit is the right answer for your patio.