A block chimney is a safe and efficient way to vent the exhaust gases from your wood stove while providing proper insulation and structural support. In this guide, we’ll provide clear and concise instructions on how to build a block chimney for a wood stove, suitable for both technical and non-technical audiences.
Materials and Tools You’ll Need
Before you begin, gather the following materials and tools:
Materials:
- Concrete masonry blocks (also known as cinder blocks)
- Type-S high-temperature mortar
- Firebricks
- Metal thimble
- Chimney liner (if required by local building codes)
- Galvanized chimney cap
Tools:
- Tape measure
- Mason’s level
- Trowel
- Masonry hammer
- Circular saw with a masonry blade
- Gloves and safety goggles
Step 1: Plan Your Chimney
- Determine the height and location of your chimney. Ensure it complies with local building codes, which may specify the required height above the roofline and clearance from combustible materials.
Step 2: Lay the Foundation
Start by laying a solid concrete footing below the frost line. The footing should be at least 8 inches thick and 2 feet wider than your chimney’s base.
Lay a course of solid concrete blocks on top of the footing. Use a mason’s level to ensure they are level and plumb.
Step 3: Build the Base
- Lay firebricks on top of the first course of concrete blocks. This will provide a fire-resistant base for your wood stove.
Step 4: Construct the Chimney Body
Begin stacking the concrete blocks on top of the firebrick base. Use high-temperature mortar between each block and check for level and plumb regularly.
Leave openings for the chimney liner and thimble where required by local codes. Install the metal thimble to pass the stovepipe through the wall.
Continue stacking blocks until you reach the desired height for your chimney. Typically, it should extend at least 2 feet above the roofline.
Step 5: Install the Chimney Liner (if needed)
- If local codes require a chimney liner, install it according to the manufacturer’s instructions. It typically involves lowering the liner down from the top of the chimney and connecting it to the stovepipe.
Step 6: Cap Your Chimney
- Place a galvanized chimney cap on top of the chimney. This will prevent rain, debris, and animals from entering your chimney.
Step 7: Inspect and Maintain
- Regularly inspect your chimney for signs of wear or damage, especially at the joints. Repair any mortar cracks promptly to maintain the structural integrity of the chimney.
Conclusion
Building a block chimney for your wood stove is a practical and cost-effective way to ensure safe and efficient venting of combustion gases. Remember to consult local building codes and regulations to ensure your chimney meets safety requirements. With the right materials and tools, you can complete this project successfully and enjoy the warmth and comfort of your wood stove.