How to Build a Brick Chimney

The major function of the chimney is to vent out the combustion produced. This helps in protecting the structure from the fire and its by-products. The chimney plays with the dangerous element of fire, so building it requires careful planning and a vigilant eye. Though all brick chimneys serve one purpose, they vary in size, height and color. Brick chimneys cannot be built in factories, and must be constructed on site.

Every brick chimney consists of five basic parts:

1. chimney cap
2. crown
3. flue
4. damper
5. clean-out door

Step 1—Study Building Code Requirement

Before starting with the construction of the brick chimney you must find out the codes of building a chimney implemented in the respective locality. One chimney design may not fit all buildings designs. The chimney’s height and size varies according to the building in which it is to be made. You should consult the building code before designing a chimney.

Step 2—Prepare a Blueprint

It is always a good idea to have a rough layout drawn on a paper to refer to when building a chimney.

Step 3—Construct the Structure

Start by building a fire box with fire bricks. The fire box is the inner most part of the chimney. Normal bricks should not be used for this purpose since they are not resistant to acid and thermal shocks. A wall must be built around the fire box. Both should at the same level. After building the wall, the gap between the box and the wall should be filled with bricks and mortar. A damper, which is air-tight, comes next. The spaces around it should be filled with mortar. Fit a flue around the damper while constructing the smoke chamber. The flue in the smoke chamber should be very secure. The rest of the chimney is constructed in a normal way, which may or may not have the same height as the roof. Build a sloping crown around the top in order to prevent rain and snow from entering the chimney. Fill the sides of the flue with mortar, leaving the top visible. Cap the flue with a chimney cap.

Step 4—Finishing Up

Carefully remove the scaffolding, and store away the tools. Make sure that you remove any excess mortar splatters promptly before they harden and become difficult to remove.

Step 5—Cement Curing and Testing

Once the structure is completed, you will need to allow the mortar to cure for at least 3 to 4 days. Once this curing period is complete, you can test your chimney with a small fire to make sure that the smoke is channeled properly and make any adjustments before commissioning the chimney for regular use.