Planning Your Outdoor Fireplace
Before you begin constructing your outdoor fireplace, take the time to properly plan the project. This includes deciding on its location, design, size, and the materials you will use.
Choosing the Location
Select a spot for your fireplace that is at least 10 feet away from your home, trees, and any other structures to prevent fire hazards. Consider wind direction and ensure that the location you pick doesn't cause smoke to enter your home. The ground should be level, and you might need to prepare a solid foundation, such as a concrete slab, depending on the weight of the structure.
Designing the Fireplace
When designing your fireplace, think about how it will blend with your outdoor space and style of your home. Plan for features like a hearth for seating, a mantel, and space for wood storage if desired. Keep in mind the aesthetic you wish to achieve, whether it's modern, rustic, or somewhere in between.
Determining Size and Dimensions
Your fireplace should be proportional to the size of the space and accommodate the amount of seating you desire. Standard outdoor fireplaces range from 36 to 44 inches wide and 24 to 36 inches deep. Heights typically vary from 7 to 9 feet. Make sure you also account for chimney dimensions, which should be designed to ensure proper smoke draw.
Selecting Cinder Blocks and Materials
You'll need cinder blocks that are specifically rated for fire safety. Consult with a local building supply store to choose the right ones. Additionally, you'll require:
- Mortar mix: To secure the blocks.
- Firebrick: For the interior of the firebox.
- Fire-resistant adhesive: For added security in joining blocks.
- Grate and spark screen: Vital for safety and maintenance.
Be aware that the type and quality of materials you select directly influence the durability and safety of your outdoor fireplace.
Foundation and Safety
Before you begin, it's crucial to establish a solid foundation and consider safety features. A secure foundation prevents structural issues, while correct ventilation and fire safety measures protect against potential hazards.
Laying the Foundation
The foundation supports the weight of your fireplace and prevents ground moisture from damaging the structure. Start by digging a trench approximately 12 inches deep and at least 3 feet wider than the planned fireplace dimensions. Fill this with a 6-inch gravel layer, compact it, and add a 4-inch layer of concrete. Let the concrete cure for at least 48 hours. Ensure the surface is level, as this will ensure stability and longevity of the fireplace.
Ensuring Proper Ventilation
Proper ventilation is critical for safe operation and to minimize smoke exposure. When constructing your fireplace, ensure there's an air inlet at the base and a chimney or smoke duct at the top for efficient airflow. This allows oxygen to feed the fire and channels smoke away from users. The dimensions for the chimney should be at least 12 inches by 12 inches to promote adequate air draw.
Considering Fire Safety
To ensure fire safety, maintain a minimum distance of 10 feet from any structures or flammable materials. Use fire-resistant mortar for assembling cinder blocks and install a fireproof liner inside the firebox. This adds an extra layer of protection and prolongs the lifespan of the fireplace. Regularly remove ash and debris to prevent clogging and check for cracks or damage before each use.
Building the Fireplace Structure
Building an outdoor fireplace with cinder blocks requires attention to detail and adherence to safety standards. Ensure the structure is robust and the design reflects your needs.
Preparing the Base Layer
Start by choosing a level site for your fireplace, away from any structures or overhanging trees. Mark out a 5-foot by 3-foot area. Dig down 6 inches and fill with a 4-inch layer of gravel for drainage. Tamp the gravel until it's compact. Next, add a 2-inch layer of sand on top for a level and stable base. Use a level to check the surface.
Stacking Cinder Blocks
Outline the perimeter of the fireplace on the base with a row of cinder blocks. Check the alignment of the blocks with a level and adjust as necessary. Apply mortar to the bottom of each cinder block and place them carefully, ensuring they are straight and level. Leave space on one side for the firebox opening. Continue building walls by placing cinder blocks in staggered rows until you reach the desired height.
Creating the Firebox
The firebox should be centered on the base, leaving at least 12 inches from the edges for insulation. For the interior of the firebox, use firebricks laid on a bed of fireproof mortar. This will ensure the firebox can withstand high temperatures. Arrange the firebricks so the smooth side faces the interior of the firebox for easier cleaning.
Forming the Chimney
The chimney is vital for drawing smoke upward and away from the firebox. It should be constructed above the back part of the firebox using cinder blocks. Maintain a minimum width and depth of 12 inches for the chimney flue throughout its height. Increase the height of the chimney in increments, securing each block with mortar until it extends at least 3 feet above the firebox or as required by local regulations. Use a chimney cap to protect against rain and downdrafts.
Finishing Touches
Once your outdoor fireplace structure is in place with cinder blocks, adding finishing touches can enhance both its durability and appearance. These final steps will ensure a polished and functional fireplace that complements your outdoor space.
Applying Surface Treatments
To start, seal the cinder block surface to protect it from the elements. Use a high-quality masonry sealer, applying it with a paintbrush or roller for even coverage. This will help prevent moisture from seeping into the pores of the concrete and causing damage over time. For aesthetic appeal, you can apply a surface bonding cement which allows for a smoother finish and can then be painted using masonry paint in the color of your choice.
Installing Firebrick
Inside the firebox, the installation of firebrick is crucial to reflect the heat and protect the cinder block from the intense heat of the fire. Place firebricks on the floor and against the walls of the firebox in a staggered pattern for maximum stability. Use refractory mortar to adhere the bricks together since it can withstand high temperatures without deteriorating. Ensure each brick is level and the joints between them are even.
Adding a Mantel and Hearth
For the mantel, select a piece of natural stone or a weather-resistant wooden beam that complements the look of your outdoor space. Secure the mantel above the fireplace opening using masonry anchors and ensure it's level. The hearth should be constructed from fireproof materials, and extend at least 16 inches in front of the firebox for safety. Tiles or stone slabs are popular choices for a hearth as they offer durability and are easy to clean.
Accessories and Features
Enhancing your outdoor fireplace with the right accessories and features can improve its functionality and safety. Choose additions that complement your design and meet your outdoor heating needs.
Selecting Grates and Screens
Grates are essential for proper airflow and efficient burning of wood. Identify grates that fit snugly within the dimensions of your cinder block fireplace. Material should be durable, typically made of cast iron or welded steel to withstand high heat.
| Grate Size | Material | Durability | Suitable For |
|---|---|---|---|
| Small | Cast Iron | High | Limited space usage |
| Medium | Steel | Moderate | Standard fireplaces |
| Large | Cast Iron | High | Larger gatherings |
Screens are vital for safety, protecting you from stray sparks and embers. Choose a screen made from heavy-duty metal like wrought iron or stainless steel and ensure it's the appropriate size for your fireplace opening.
Incorporating a Wood Storage Area
Having a dedicated wood storage area adds convenience and keeps firewood dry and ready to use. Build this area into the structure of your fireplace or design a separate compartment adjacent to it. Consider:
- Location: Store wood at a safe distance from the fire to prevent accidental ignition.
- Capacity: Ensure your storage area can hold an ample supply of firewood for extended use.
- Protection: Use a cover or roof to shield firewood from the elements.
Building a built-in wood storage compartment should align with the overall design and proportions of your fireplace to maintain aesthetic and structural integrity.
Maintenance and Upkeep
To ensure your outdoor fireplace endures, regular maintenance is pivotal. Your fireplace is exposed to the elements and requires attention to maintain its structural integrity and appearance.
Weekly Cleaning:
- Remove ashes and debris after each use to prevent accumulation and possible corrosion.
- Wipe down the cinder blocks with a dry cloth to eliminate dust and ash traces.
Monthly Inspection:
- Cracks and Damage: Look for any signs of cracks or damage on the cinder blocks. Small cracks can be sealed using masonry or silicone sealant.
- Mortar Joints: Check the condition of mortar joints between cinder blocks. If the mortar is crumbling, scrape out the damaged areas and apply new mortar.
Seasonal Care:
- Winter: If you live in a region with freezing temperatures, cover your fireplace to protect it from snow and ice, which can cause the blocks to crack.
- Spring: When winter recedes, clean the fireplace thoroughly and clear any debris or leaves that accumulated over the cover.
Preventive Measures:
- Sealer Application: Apply a concrete sealer to the cinder blocks annually to provide an extra layer of protection against moisture and wear.
- Cap Installation: Consider installing a cap over the chimney to keep out rainwater and prevent deterioration.
Fireplace Grate:
- Inspect the fireplace grate for any signs of wear or warping. Replace the grate if it's damaged to ensure proper air circulation for your fires.
By adhering to this maintenance plan, you extend the life of your outdoor fireplace and ensure it remains a welcoming centerpiece for your gatherings.