Building an outdoor fireplace with cinder blocks is a cost-effective, durable, and customizable way to create a cozy gathering spot in your backyard.
From planning and design considerations to constructing the chimney, there are a lot of things you need to conduct properly to build an outdoor fireplace with cinder blocks.
And with finishing touches like stucco or stone veneer, your cinder block fireplace can blend seamlessly into any outdoor design.
So, ready to transform your backyard into the ultimate gathering place? Keep on reading to learn the entire process of building an outdoor fireplace with cinder blocks, from planning to finishing touches.
Let’s dive in and get started!
Why Must You Build an Outdoor Fireplace with Cinder Blocks?
Cinder blocks are a popular choice for outdoor fireplaces for several reasons:
- Cost-Effective: Compared to other materials like stone or brick, cinder blocks are much more affordable while still offering durability.
- Easy to Work: Cinder blocks are uniform in shape and size, making construction easier for beginners.
- Durability: They are resistant to weather conditions and can withstand the heat generated by a fire.
- Customizable: Cinder blocks can be easily covered with stone veneers, stucco, or painted to achieve the desired look.
For these reasons, they are perfect for anyone looking to build an outdoor fireplace without breaking the bank or dealing with overly complex materials.
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Materials and Tools Needed
Before you start building your outdoor fireplace, gather all the necessary materials and tools. Here’s a list of what you will need:
Materials:
- Cinder blocks (the number depends on the size of your fireplace)
- Firebrick (for the firebox)
- Fire-resistant mortar
- Concrete (for the foundation)
- Rebar (for additional support in the foundation)
- Gravel (for foundation drainage)
- Metal grate (for the firebox)
- Stucco or stone veneer (optional for finishing)
- Heat-resistant adhesive (if attaching finishing material)
- Chimney cap (optional)
Tools:
- Shovel
- Trowel
- Level
- Tape measure
- Hammer
- Chisel
- Masonry saw (if needed for cutting cinder blocks)
- Wheelbarrow (for mixing concrete)
- Safety gear (gloves, goggles, etc.)
Planning and Design Considerations
Make sure you give your outdoor fireplace plenty of thought before breaking ground. Consider the following:
- Location: Choose a spot that’s away from flammable materials such as trees, fences, or your house. Make sure there’s ample room around the fireplace for seating and safe movement.
- Size: Determine how big you want the fireplace to be, considering both your available space and how many people you want to accommodate around the fire.
- Local Building Codes: Check with your local authorities about any regulations or permits needed for building an outdoor fireplace.
- Chimney: Decide whether you want a tall chimney to direct smoke away from your seating area, or if a simple opening will suffice.
Step-by-Step Guide to Building the Fireplace
Once you have a clear plan, you’re ready to start building!
1. Preparing the Foundation
The foundation is critical to the stability and longevity of your outdoor fireplace.
- Mark the Area: Use stakes and string to outline the area where the fireplace will be built.
- Excavate: Dig a hole about 6-8 inches deep in the marked area. Make sure it’s level.
- Add Gravel: Fill the hole with 3-4 inches of gravel to help with drainage.
- Pour Concrete: Mix the concrete and pour it into the hole. Insert rebar into the wet concrete for extra stability. Use a trowel to smooth the surface and ensure it’s level. Let the concrete cure for at least 24 hours before proceeding.
2. Building the Fireplace Base
- Lay the First Layer of Cinder Blocks: Once the foundation is set, place the first layer of cinder blocks around the perimeter. Ensure they are level as you lay them.
- Add Mortar: Apply a layer of fire-resistant mortar between the cinder blocks to hold them together.
- Build Up the Base: Continue stacking cinder blocks, applying mortar between each layer. Build the base to the desired height, typically around 3-4 feet.
3. Creating the Firebox
- Plan the Opening: The firebox is the area where the fire will burn. Leave an opening in the center of the base that’s about 2 feet wide and 18 inches tall.
- Line with Firebrick: Firebricks are specially designed to withstand high temperatures. Line the inside of the firebox with firebrick, attaching them with fire-resistant mortar.
- Install the Grate: Place a metal grate inside the firebox to support the wood and allow air circulation.
4. Constructing the Chimney
- Build the Walls: Continue building up the walls of the fireplace, leaving a space for the chimney above the firebox.
- Create a Flue: As you stack the cinder blocks higher, leave an opening for the chimney flue to vent the smoke.
- Optional Chimney Cap: To prevent rain from entering and animals from nesting in the chimney, you can install a chimney cap.
5. Adding Finishing Touches
Once the structure of the fireplace is complete, you can enhance its appearance:
- Stucco: Apply a layer of stucco to give the fireplace a smooth, finished look.
- Stone Veneer: Attach a stone veneer to the cinder blocks using heat-resistant adhesive for a rustic, natural finish.
- Painting: If you prefer, you can paint the cinder blocks using heat-resistant outdoor paint to match your backyard’s aesthetic.
Cost of Building an Outdoor Fireplace with Cinder Blocks
Building an outdoor fireplace with cinder blocks can vary significantly in cost depending on the size, materials, and whether you choose to do it yourself or hire a contractor. Here’s a breakdown of potential costs:
Estimated Total Cost for DIY
If you want to build the fireplace on your own, the total cost of the project, including all the materials (blocks, mortar, concrete, extra materials, foundation, and veneer), will be around $1,345.
- Cost of Cinder Blocks: For a design requiring 150 cinder blocks at $1.00 each, the cost totals $150.
- Mortar and Concrete: If you need 10 bags of mortar at $4.00 each and 15 bags of concrete at $3.00 each, this adds $40 for mortar and $45 for concrete, for a combined total of $85.
- Additional Building Materials: For other essentials like firebrick, wood, angle iron, and rebar, estimate around $300.
- Foundation Costs: Pouring your own foundation could cost around $300 for materials.
- Veneer Finish: If you choose a veneer finish, expect to spend approximately $500.
Estimated Total Cost for Professional Installation
The total cost to have a contractor construct the outdoor fireplace could be anywhere from $6,725 to $8,070, including the cost of materials and labor.
- Material Cost: The base cost for materials is the same $1,345 as mentioned above.
- Labor Costs Estimate: In the Arizona area, labor typically costs 4 to 5 times the material cost. This means labor would range from $5,380 (4 times) to $6,725 (5 times) based on the material cost.
These figures are rough estimates and can vary based on the contractor, location, and any additional factors involved.
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Safety Tips for Using Your Outdoor Fireplace
Safety is crucial when using an outdoor fireplace. Keep the following tips in mind:
- Always use fire-resistant materials like firebrick and mortar.
- Keep flammable objects and materials at least 10 feet away from the fireplace.
- Install a spark screen or fire guard to prevent embers from escaping.
- Never leave the fire unattended, especially with children or pets around.
- Have a fire extinguisher or a bucket of sand nearby in case of emergencies.
Maintenance and Care
To ensure your outdoor fireplace lasts for years, regular maintenance is essential:
- Clean the Firebox: After each use, remove ashes and debris to prevent buildup.
- Inspect for Cracks: Regularly check the firebrick and mortar for cracks or damage and repair as needed.
- Chimney Cleaning: If you have a chimney, clean it periodically to remove soot and prevent blockages.
- Protect During Winter: If you live in an area with harsh winters, cover the fireplace or use a weatherproof sealer to protect it from the elements.
Wrapping Up
Building an outdoor fireplace with cinder blocks not only enhances the ambiance of your backyard but also provides a practical and beautiful centerpiece for outdoor gatherings.
Whether you finish it with a stone veneer or keep the cinder blocks exposed, your outdoor fireplace will offer years of warmth and enjoyment.
Take the time to plan carefully, prioritize safety, and enjoy the process—your backyard retreat awaits!
