How to Build and Install a Fireplace Throat [Steps]

  • A chimney throat refers to a contracted opening between a fireplace and the chimney. This part allows for a seamless flow of smoke out of the flame box.
  • If you intend to build a safe smoke chamber, consult an expert to guide you.
  • Acquire the best but cheap materials for your chimney throat. You may go for brick as you can customize it to your taste
  • Ensure other parts of the fireplace are accurate in measurement. This will give you an easy time erecting the fireplace throat.

How to build and install a fireplace throat

Are you looking forward to a great evening in front of your fire? Ensure that you vent out the smoke safely if you want to enjoy your fire. This means you have to construct your chimney in the best way possible.

Smoke can irritate you, and if you are allergic, it may spoil your wonderful moments. You ought to ensure that the chimney throat and the chimney have a seamless connection. This will make the smoke flow out into the chimney without inhibition.

Your fireplace throat is a connection to the chimney smoke chamber. It is dependent on other structures. There are many factors you will have to consider before erecting your throat;

  1. Consider the size of your fireplace and flame box.
  2. The type of wood or waste you will be burning to provide heat and fire.
  3. The materials you intend to use to construct the throat.

Kindly read through this article to guide you on how you will build your flame place throat. The steps highlighted herein are simple to follow and apply.

The Base or Foundation

Before you get down to building your flame place throat, you will have to start from the base of the fireplace. Since it will be supporting the chimney, use ferroconcrete (a mix of cement concrete and steel bars). The mixture will increase the tensile strength of the base.

Once you have the foundation in place, erect the platform walls. Ensure that they are at least 10 to 12 inches thick. This thickness will withstand the fires you make.

The Groundwall Top

You will have to place L-shaped steel (angle steel) on top of the base. The angle steel should measure 4 by 6 inches. Lay blocks on the angle steel three rows up and use mortar to hold the blocks in position.

The Outside Walls

The outside wall is easy to erect. You may opt to use used bricks or blocks if you cannot afford new ones. Apply adequate mortar to increase the strength of the wall. Use Type N mortar to parge the inner walls.

Parging your walls is essential as it will prevent any leakages. During the winter, your walls will take a beating from the heavy rains or snow. When you use waterproof mortar, you are sure that the wall will withstand the harsh weather.

Fireplace or Hearth

Once you finish building the outside walls, you can erect the fireplace wall. You can use concrete blocks to build the hearth course by course. The hearth must be accurately built so that the throat also fits with ease.

The fire you will make will have to vent out its smoke seamlessly through the throat into the chimney. Any miscalculation when constructing your hearth may lead to the smoke blowing back into the house.

The Furnace (Firebox)

Now that you have your fireplace erect your interior hearth. You will have to use the required and accepted bricks. Lay your bricks closer to each other and use adequate cement to seal off any opening.

Lay the sidewall bricks and the back wall on their sides. Make their shiny positions face inwards. You may use the refractive cement as you lay these bricks.

The Damper

The damper plays an integral role in the fire and smoke venting mechanism. Set up an overlay (lintel) across your flame place. The lintel ought to cover wall to wall in order to support your valve.

Pour enough cement on the lintel to seal off any opening. You should do this to ensure that fumes do not seep through the flame place face. Once you are sure the overlay is in place, build 3 to 4 courses on top of it.

After fitting the courses, you can fit the damper. Insulate the damper with nonflammable wares. This will make it safe for operation.

The damper will regulate the rate at which your fire burns. Apart from regulating the fires, it plays a vital role in keeping your firebox safe. With the damper in place, you are sure your room is safe from draft.

Fire Throat (Chimney Throat)

Do you remember the 4 courses you built above the damper? Your throat is almost done at this point. With keen precision, curve or corbel the front and sidewalls to about one and a half inches.

You only need to corbel the three walls to fit the chimney’s flue. The angle at which you will corbel your throat should be 45 degrees. Make sure that the rear wall is straight all through. Doing this will guarantee you a smoke-free room.

To ensure that your fireplace does not suffer smoke seeping back, consider doing the following;

  1. Smoothen the interior of the chimney throat. Smoothening the inner walls allows the smoke to flow freely through the chimney.
  2. Use parging cement to give your throat a smooth finish. You may carry out the filling step by step to seal all holes. Use chamber coat, chamber tech 2000, and smok tite to parge the walls.
  3. Ensure that the walls are not less than 8 inches. The walls of the smoke chamber have to be thicker to withstand the fire.

Building a flame place throat by yourself may seem daunting. However, it is easy to construct yours from scratch or the hearth. You will get it right if you stick to the specifications and measurements.

Do not fear getting dirty or messing a bit. By following the guide above you will have your fireplace in no time. Should you have doubts about your expertise, you can consult your local construction authority.

Eugene Duke Pic

Hi, my name’s Eugene Duke and I love sitting by my fireplace reading a book and sipping on an adult beverage. Do you have a fireplace in your house? I’ll help you figure out the best type and style of fireplace for your home.


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