How to Build Outdoor Fireplaces

Three Parts:Planning the BasicsChoosing a DesignBuilding the Fireplace

Outdoor fireplaces can be breathtaking additions to homes, giving backyards a decorative and functional focal point. However, outdoor fireplaces demand thoughtful assessments even before you begin construction, especially if you intend to make an outdoor fireplace from scratch. If you want to build an outdoor fireplace that will last you a lifetime, follow these guidelines.

Part 1
Planning the Basics

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    Consider what purpose you want your outdoor fireplace to serve. Reasons for building an outdoor hearth vary, but whatever yours are, you will want to consider certain elements to bring your project to a successful conclusion.
    • Ambience: Fireplaces can set the mood. A cozy open hearth provides an intimate setting for small groups. If you throw large parties, consider building a fireplace with two open ends to accommodate more people. A fire pit provides views from all vantage points and the feel of a campfire setting.
    • Functionality: You can build a fireplace that also serves as a barbecue or pizza oven, but these designs are very complex.
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    Consider the design of the hearth. Many homeowners match the stonework of their fireplace to the stonework of their residence, although it's not mandatory. Brick offers a more traditional stone façade, while man-made stacked stone gives the hearth more of a contemporary look.[1] If you don't want to go for a stone exterior, stucco is also a popular option.
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    Determine the size of your fireplace. The size of your fireplace should be scaled to its surroundings. Consider whether you want your fireplace to be the focal point of your back yard, or to complement an already-stunning vista.
    • Try to design the fireplace with proportions in mind. You don't want your fireplace to completely overshadow the size of your house; nor do you want the fireplace to be dwarfed by your home.
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    Decide on wood-burning or gas. What type of fireplace is best for you? Most outdoor fireplaces are either wood-burning or gas, and each offers certain advantages and drawbacks:
    • Wood-burning fireplace offers natural sights, sounds and smells of a fire that gas units simply cannot match. A traditional fireplace will also produce a significant amount of smoke, and therefore must have a chimney built to strict specifications.
    • The primary consideration in building a gas fireplace is safely connecting the hearth to an existing gas line. Gas fireplaces offer many advantages over wood-burning hearths: they produce no ashes or embers, don't require a chimney, and seldom require construction permits. Still, they don't burn as hot and lack the rustic charm of a wood-burning unit.
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    If building a wood-burning fireplace, obtain a building permit. Most wood-burning units require permits. Contact your municipal government about setback restrictions and other requirements. You can begin construction after being issued a building permit.
    • The city will need to inspect the fireplace before you can use it.
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    Find your gas line if you want to build a gas fireplace. Your gas company can help you locate the line nearest your fireplace location.

Part 2
Choosing a Design

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    Choose a fireplace kit for ease of assembly and efficiency. Fireplace kits really run the gamut, ranging from simple affairs to ornate pieces, replete with all the bells and whistles. The great thing about fireplace kits is that you can usually opt for a wide variety of styles that will fit your budget. Got a smaller budget? No problem, there's a kit for that. Working with a bigger budget? The sky is almost literally the limit.
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    Make your own design. So you fancy yourself a builder, or maybe you're a mason? Why settle with a pre-bought kit when you can build the design that's in your own head, without having to compromise? Most self-made designs employ cinder blocks or another sturdy, economical material as the skeleton. The skeleton is then covered with stone or another veneer stone after the cinder block is laid. Consider the three main elements of your outdoor fireplace when crafting the design:
    • Base: A reinforced concrete base is the best base you can have for a fireplace. Custom fireplaces are usually heavier than prefab fireplaces, meaning your base needs to be stronger and thicker than ordinary.[2]
    • Firebox: Your firebox will house the fire, and should sport fire brick if custom built. On the other hand, you can purchase a firebox (choices of material include stainless steel and other types of brick) if you don't want to build it yourself.
    • Chimney or Vents: A wood-burning fireplace will require a chimney with a spark arrestor, while a gas-lit fireplace will only require vents.
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    Plan on adding any additional features to the fireplace area. Your fireplace doesn't merely need to be a hearth. In fact, if you're building an outdoor fireplace, it makes sense to outfit it with other uses or aesthetic furnishings. Consider:
    • Built-in seating. Warming yourself by the heat of the hearth is a real treat, so why not build seat walls as an extension of the fireplace itself? It looks wonderful and adds instant charm to any outdoor fireplace.
    • Wood storage. Convenient if you're building a wood-burning fireplace, a compartment or space for wood will make stoking the fire easy and painless.

Part 3
Building the Fireplace

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    Pour the concrete for the foundation, if you haven't already. Set up the foundation first by digging a trench and using a plate compactor to shore up the foundation. Mix and pour the cement and allow it to set for at least 24 hours, if not longer.
    • Check with local building authorities to see how low you'll need to dig your foundation. Some locations will need foundations of concrete only 6 inches (15.2 cm) deep, while others will need to be in excess of 1 foot (0.3 m).
    • Note: Concrete and mortar, although similar, are different bonding agents and should be used differently. You'll use the concrete to lay a foundation, if necessary, and the mortar in order to bond concrete or cinder blocks together.
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    Spread mortar onto the foundation and begin laying your concrete or cinder blocks. Follow the building plans precisely, making sure that each row of blocks is level.
    • When creating the base, be sure to use a level in order to ensure a balanced placement of the concrete or cinder blocks.
    • If building using cinder blocks, spread mortar in between each row, as well as in between individual pieces of cinder block.
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    If necessary, lay out your fire brick inside your firebox. Fire brick should take special care when installed inside a firebox: Laying a pleasing-looking pattern and mixing the right mortar is an important consideration.
    • Choose a nice inlay pattern with which to set the fire brick. A running bond pattern works nicely in a firebox. Find the center of the firebox and trace a line all the way to the face of the firebox.
    • Place a fire brick immediately to the left and to the right of the bisecting line, flush against the face of the firebox, leaving about 14 inch (0.6 cm) space in between the two. Lay one brick immediately above the two bricks, offsetting it by placing it exactly in the middle. Above it, lay down two bricks in the same pattern as originally placed.
    • Mix your mortar with high-temperature mortar. This way, the high temperature of the fire won't compromise the mortar that's holding the fire brick together.
    • When laying down the brick, cut it as necessary at corners and edges. While you should be able to get by without having to cut the center pieces of the firebox, corners and edges will force you to the fire brick down to size.
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    Remove any air bubbles from the fire brick mortar with a jointer and a brush. Pack in the mortar in each seam with a jointer. Then, dust away any excess mortar with a clean brush, leaving your firebox to dry to at least 24 hours.
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    Construct or add a chimney for wood-burning fireplaces. The chimney must be built to exact specifications to ensure proper draw of the smoke from the firebox. It must have a smoke shelf to reduce down-draft and a flue of optimum dimensions. The chimney also must be at least 2 feet (0.609 m) higher than any adjacent structures.
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    Add the spark arrestor. Like chimneys, spark arrestors are exclusive to wood-burning fireplaces. They trap embers from the hearth.
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    Install the hearthstone. The hearthstone is the lip of your fireplace opening, perhaps the focal point of your outdoor fireplace. Installing it correctly is an important part of building an outdoor fireplace.
    • Place mortar in three 3/4-inch deep strips, 1 inch (2.5 cm) from each other.
    • Set down the hearthstone, using a rubber mallet and level to make sure that it's plumb and level. If the hearthstone isn't flush with the firebox, that's okay. This will make it harder for any sparks to fly out of the front of the firebox.
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    Select a stone style for the veneer. Apply mortar to the back of the stones and stick them onto the cinder blocks. Use spacers to separate stones, filling in the area between them with mortar.
    • At perfect 90 degree corners, avoid continuous joints that travel all the way down the length of the fireplace. Instead, tooth them. Place the first stone flush on a corner, and then bring another stone out an inch or so to meet it. With the next two stones, alternate the joint: Bring the first stone out, and then place the second stone flush on the wall. This creates an attractive-looking alternating pattern running down the corners of the fireplace.
    • Once laid, allow the mortar at least 24 hours to harden. If possible, give the fireplace several days of rest before attempting to use.
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    Connect your gas-burning fireplace to the gas line. If building a gas-burning fireplace, prepare to hook up gas to your fireplace in order to get it working.
    • Turn off the gas.
    • Use plumber's putty on the threads of the main line to connect it to the flexible lines.
    • Tighten the connection with a wrench until the fitting seats. Test the connection by spreading dishwashing soap on it.
    • Turn on the gas. If bubbles appear, refit the connection.
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    Finished. You've successfully added value to your home, revitalizing your backyard. Enjoy your new outdoor fireplace!


  • Consider building your fireplace from a kit. Fireplace kits take much of the guesswork out the construction process. Most feature modular designs, complete instruction manuals, and can be built in just a few days. They also meet critical specifications on chimney and firebox construction. You will have buy stone finishing separately.
  • Consider building a patio around your fireplace, especially if you're using your fireplace for cooking.

Things You'll Need

  • Detailed construction plan
  • Masonry, including stone finishing, bricks, concrete blocks and ceramic bricks for the firebox
  • Fire-retardant grout
  • Hand trowel
  • Mortar mix
  • Carpenter's level
  • Duct or pipe to serve as the flue
  • Wheelbarrow
  • Clay tile for flue liner
  • Metal grate to hold the wood in the hearth
  • Pre-fabricated metal damper
  • Screened flue cap

Article Info

Categories: Candles Lamps and Fireplaces | Landscaping and Outdoor Building