How to Build Smoke Stacks

Foundation

• 1

  Dig a hole in the ground for your foundation. The hole should be 2 1/2-feet deep at the edges and 1-1/2 feet in the center. It should be 6-feet wide-by-6-feet long. The portion that is 2 1/2-feet deep should be separated from the portion that is 1-1/2-feet deep by a 30-degree incline.

• 2

  Cover the bottom of your hole with a 3-to-6-inch layer of gravel. The layer of gravel should be the same thickness throughout the hole, so as to retain the differences in depth and the incline.

• 3

  Build a rebar cage in the hole. Each of the bars that are parallel to each other should be 12 inches apart. The vertical bars should begin 12 inches from the edge of the hole and extend from the layer of gravel to 2 inches below ground level. The horizontal bars should begin 6 inches above the bottom of the hole and extend from edge to edge. Weld the bars together where bars meet (they should form a cubic pattern).

• 4

  Fill your hole with concrete to ground level. Place one small anchor bolt where the center of each of the bricks of the first row will be laid. Allow the concrete to set and harden before proceeding any further.

Building the Stack

• 5

  Lay your first layer of bricks on top of the foundation. Lay the bricks in a circular pattern, with the circle having a diameter of 4 feet at the center. The first row of bricks should have holes in the center, fitting over the anchor bolts. Fill the gaps between bricks with mortar, using your trowel to smooth the mortar as necessary. The rim of the circle should be two bricks thick, in the Flemish bond pattern (see "Resources"), but leave three of the spaces for header bricks empty.

• 6

  Place steel gutters in the empty spaces in the first row. This will provide drainage for rainwater. These should be equal in size to the bricks and enclosed on the top, bottom, left and right.

• 7

  Continue to build your circular Flemish bond wall, using your trowel to apply mortar everywhere any two bricks will meet, and build around your furnace's exhaust duct.

• 8

  Use your trowel to apply concrete, filling in the empty spaces around your furnace's exhaust duct.

• 9

  Continue building your Flemish bond structure until it is 20 feet high; use a cherry picker to access heights beyond your reach.