Building A Brand New Chimney
When building a new masonry chimney, there are several important factors to consider, including flue size, chimney height, and compliance with local building and safety codes. It requires careful attention to not only aesthetics, but it must be functionally efficient as well. It must also be able to withstand changing weather conditions, high temperatures of a roaring fire, and venting of smoke and gases. Here’s something else to consider: The chimney is often the heaviest part of the home, so it is best to consult with a local chimney specialist with experience in chimney construction.
Just like any other structure, chimneys need to comply with local building codes and safety regulations. Your municipality may also require the submission of architectural drawings before issuing a construction permit for building a masonry chimney. It may also need final approval by your local building inspector when construction is complete.
There is no one-size-fits-all chimney. The manufacturer of your fireplace will recommend the correct flue size, including minimum height requirements that will be necessary for your chimney.
However, the actual height of the chimney will need to be at least two to three feet higher than your roof, unless otherwise mandated by local building codes. It will also need a strong 8 to 12-inch concrete footing at the base to support the weight of the heavy brick structure. There will also need to be a 6-inch clearance between the base and your home.
Many chimneys are attached to the exterior of the home, but this is not always the best placement, especially in cold climates. The cold outside air cools down exterior facing chimneys during the winter expelling the heated air in what is known as the stack effect.
Constructing the masonry chimney within the building envelope of the home is an ideal location that will also increase energy efficiency. It insulates the chimney against fluctuating external temperatures, thus negating the stack effect. Therefore, you will enjoy warmer and longer-lasting fires.
Also, exterior facing chimneys generally require an 8-inch wall surrounding the flue to withstand weather conditions. An interior chimney usually requires a 4-inch thick brick wall.
Your new brick masonry chimney will also need a flue liner that is appropriately sized for your flue. The liner helps retain the heated air inside the chimney while preventing the heat from transferring to combustible construction materials. The three most common flue liners are clay tile, cast-in-place cement, and stainless steel. Clay tile liners are the least expensive but require frequent maintenance and repairs. Although a stainless-steel liner is more expensive, it is virtually maintenance-free and increases the heating efficiency of your fireplace.