How to Extend Chimney Flues
If your chimney is free from obstructions and the damper is functioning properly, and yet smoke finds its way to the living room, it means that your draft may be weak or that your chimney is too short. A good chimney should be not less than three feet above the roof or at least two feet higher than any structure close to it. Having a short chimney, and regulations are a reasons to extend it.
Equipment Needed:
- A hammer and nails
- Tape
- Chisel
- Fireplace mortar and mortar mix
- A trowel
- Caulking gun
- Wire brush
- Plastic sheeting
- Terra cotta flue extension
- 2 by 6 lumber
- Use the chisel and a ballpoint hammer to get rid of the old crown in the region of the flue lining. In order to prevent damage to the flue, chisel away from it and prevent the debris from falling down to the flue.
- Use the wire brush to clean the top part of the flue liner and afterwards apply the fireplace mortar alongside the edge using the caulking gun. Put the terra cotta liner extension directly over the current liner.
- Use the bricks to build a wall up to the height of the newly placed liner, ending only about eight inches from the top of the flue extension.
- Create a form out of the 2 by 6’s at the top of the chimney and place it there so that it appears to hug the sides of the chimney tightly. After that, put in a batch of mortar into the form according to the instructions of the manufacturer.
- Slope the crown up using the masonry trowel towards the flue liner, at which time the mortar is stiffening. Make sure you leave up to four inches of the liner exposed.
- Pour water over the mortar using the garden hose and fasten the plastic sheeting on the mortar to keep it dump for several days.
- Eliminate and remove the frame as soon as the mortar has cured.