How to Build a Brick Chimney in a Brick House

Inspect your house to determine if you need to build a complete exterior chimney, or if there is a flue leading up through the house and you only have to build the top part.

Purchase a clay chimney liner that matches the length of the chimney. Make sure to purchase a liner that has a 10-inch or 12-inch opening on the inside. Fireplaces need this large of a chimney for safety. This gives the fireplace enough room to disperse the heat from the fire safely, without burning the liner walls.

Attach the liner to the fireplace with mortar. Allow to dry for 24 hours.

Cover the bottom 2 feet of liner with mortar. Work with 1 or 2 feet of chimney at a time. Cover the liner with the bricks. Using a pastry bag, apply mortar between the brick layers. Spread out the mortar with a trowel.

Smooth the mortar between the joints with your fingers or a damp rag. This will help give the bricks a uniform appearance.

Continue to install the bricks until you reach about a foot from the chimney liner top. Glue the chimney cap on the top brick layer with mortar. The cap should stick out about 2 inches from the bricks. The cap will prevent water from dripping down inside the chimney when it rains or snows.

Allow the mortar to dry for 24 hours. Attach the top of the chimney to the roof using roof flashing. Glue the flashing to the chimney and the roof using mortar. Allow the chimney to dry for two days before using the fireplace.

Rinse the chimney off with a garden hose and scrub the front of the bricks with a scrub brush. This will remove excess mortar from the side of the chimney.