To construct a brick chimney, determine the dimensions for the inner and outer sides of the chimney, and lay the bricks over a bed of mortar. Lay around 1 foot of bricks, and install a flue tile within the chimney. Repeat the process till the chimney stands at least 3 feet up from the roof's highest point.
If the chimney is to go with a fireplace, the width between its inner sides should be a minimum of 8 inches. Inner width for chimneys with a furnace or a stove should be a minimum of 6 inches.
To determine the dimensions for the chimney's outer sides, measure the width and depth of the hearth. If the chimney is to run horizontally via walls, maintain a 12-inch clearance from materials that are combustible. In such a case, the chimney should have 8-inch thick sides. Each side of the chimney should have two brick layers.
For external chimneys, maintain a clearance of 1 inch. Mark the chimney's outer dimensions using string and stakes.
Begin constructing the chimney by laying a bed of mortar and setting the first row of bricks on it. Using the handle of the trowel, tap each brick to make it level. After completing the first brick row, check its evenness using a level, and make the necessary adjustments. Lay mortar on this row to set the second brick row in a similar fashion.
Add brick rows till the chimney attains a height of 1 foot. Now, apply mortar to the outer sides of a flue tile, and position it within the chimney. Ensure that the tile is plumb using a level.
Continue adding brick layers and installing flue tiles in a similar manner till the chimney attains the required height.