Purchase all supplies needed to build the chimney. While this may vary slightly depending on the type and location of your fireplace, you must have all the materials when you start the project.
To install a metal fireplace you will need protective sheets, a prefabricated fireplace drawer, a chimney cover, prefabricated chimney sections, and chimney roof clamps. If the fireplace goes through a wall or a roof, you must use a chimney section that is rated to cross a wall, so there is no risk of burning the wall or ceiling.
If you build a masonry fireplace, you will need to purchase bricks and masonry, mortar, support pieces (such as steel bars), protective films, a lid and specialty masonry tools.
Build the combustion chamber. You should start building the fireplace from the floor. In the case of masonry chimneys, this usually means that you will build your fireplace just from the top of a fireplace (if the fireplace was designed for this purpose), using bricks similar to those used to build the fireplace.
You will have to prepare a mixture of mortar and water, making sure it has the thick consistency of the peanut butter. After giving the proper consistency, you should use a spatula to apply the mortar to each brick before fixing them. You should apply a sufficient amount of mortar in each brick and it should overflow a little through the joints, which will ensure that the entire area between the bricks is filled with mortar.
When you are building brick walls with bricks, make sure it is level on all levels. Record a level and verify that all walls are at that level in the vertical and horizontal planes, and that in each row of bricks, all the bricks are aligned with each other.
In prefabricated metal chimneys, it is almost impossible to differentiate the combustion chamber from the rest of the chimney.
The chimney must be built on a very solid base. If you are not going to build it on an existing stove or base, you may need to create a reinforced concrete base to build the chimney over it. Check the local code to determine if this is a requirement and what specifications you must meet.
Build the duct and the outside of the chimney. The duct connects the top of the combustion chamber with the roof through the center of the chimney. As indicated in the previous section, it may be made of bricks or metal tubes. If you are going to use ceramic or clay tiles to create the conduit in a brick chimney, you should mount them in the same way that the exterior of the chimney was mounted.
Metal cladding can be fitted, while concrete cladding should be applied by pouring concrete through a flexible hose.
Surround the fireplace with protective foils at the points where it crosses a wall. You should place a metal protective sheet around the fireplace in 2 places: around the fireplace where it connects to the ceiling and as a liner beneath the fireplace cover. Apply a waterproof silicone or polyurethane sealant under the protective foils to prevent water from entering the house through the fireplace.
Cover the fireplace. Place the chimney flap over the top of the duct brick cover. You must overlap the chimney wall by at least 2 inches and must have gutter edges to divert water away from the fireplace. Recommended materials for the chimney top include stone and precast concrete or cast and cast.
The chimney lid is important because it reduces the amount of moisture that can enter the chimney, keeps animals away, blocks downstream airflow, prevents sparks from coming out of the chimney, and prevents debris (such as Leaves and branches) leave your house through the fireplace.