Anatomy of Your FireplaceOur fireplace experts at A Sweep Across the Bay in Sarasota want to help you understand the anatomy of your fireplace so that you can make sure your fireplace is working properly and safely. By understanding these special precautions and maintenance needs, you can enjoy fires on chilly evenings and provide a cozy atmosphere for gatherings with family and friends.


Industry association, the Chimney Safety Institute of America, talks about the two general types of fireplaces you might have in your home, masonry fireplace, and factory-built fireplace, and how to identify the anatomy of your fireplace.


Masonry fireplaces are built out of bricks, blocks, or stone and mortar. It has a firebox built of individual, generally yellowish firebrick, a brick chimney above the roof, and if you look up past the damper, you will see a sort of pyramid-shaped part of the chimney also built of brick.


Factory-built fireplaces consist of a lightweight metal firebox and a metal chimney. It usually has a firebox of cast refractory panels, and some metal is visible in the room all around the firebox. If you look up the damper, there will be a round metal chimney. Above the roof, there is a round metal chimney, sometimes with a simulated brick housing.


Masonry Fireplaces

These types of fireplaces are built entirely of bricks, stone, and mortar, or blocks, so, of course, they can be beautiful, big structures that often weigh between 6 and 7 tons. These types of fireplaces usually last a long time and can add real value to your house. But masonry fireplaces still need maintenance and if kept in good shape can last a lifetime.


Without an extensive footing to support its heavy mass, a masonry fireplace will often shift and crack, which could let the fire expand to nearby combustibles and that’s very dangerous. So, examine your fireplace from time to time to check for any signs of settling or movement. We advise you to always look inside the firebox where the facing material meets the firebrick. This is often the place where settling is first seen.


You should always keep downspouts directed away from the fireplace. It’s important that you slope the ground around the fireplace and chimney to be sure water runs away from the fireplace structure so you can reduce those settling and cracking problems.


Masonry fireplaces are strong and durable, but they sometimes need repairs. The eaves protect most of your house, but the chimney is exposed to the elements, including moisture and temperature changes. You should consider getting a quality chimney cover, making sure the crown is in good repair, and getting a waterproofing treatment, because they can all save you money in the long run by avoiding expensive repairs or rebuilding of the chimney.


It makes sense that the firebox takes the brunt of the fire’s heat, so the joints will eventually fail from the constant expansion and contraction. In addition, refractory mortar is recommended but often not used which can cause problems. If your fireplace doesn’t have a chimney cover, the rain water can pool on the smoke shelf, mix with the soot behind the damper, and form an acidic slurry that can seep into the fireback destroying the mortar joints. We make sure these joints are kept in good shape with a high-temperature refractory mortar to make sure the fire is contained and doesn’t spread.


As long as you maintain your tile liners and they are not exposed to chimney fires, they will be fine. But if you have a chimney fire it can crack the tiles, making them ineffective. If you do have a chimney fire call us to come and inspect it before you use it again. The general rule of fireplace maintenance is they should be cleaned before a 1/4 inch of soot accumulates. 


A masonry fireplace is built at your house, brick by brick, which gives the mason the responsibility to build a good fireplace. But not all masons have the same skills. We offer maintenance and repair suggestions to fix most problems if they exist. 


Pre-Fabricated or Factory-Built Fireplaces

These types of fireplaces have been around for about 25 years. Most factory-built fireplaces and chimney are made of metal and come complete from the factory. The units include a firebox, a specific chimney system, and all the other parts you will need. If pre-fabricated fireplaces are installed properly and maintained regularly, they can last for many years, but we want to tell you some things you need to know if this is your type of fireplace. 


The installation instructions must be followed exactly for factory-built fireplaces and chimneys. Pay particular attention to the specified clearances from the firebox and chimney to any combustible materials. Most manufacturers require a 2-inch minimum air space between the chimney components and all wood framing. If you are installing a new unit, it is important to follow these clearance instructions. If your unit is already installed, we can help you check these clearances. If there is wood that is too close to the chimney, it will continue to dry and undergo a process called pyrolysis. This wood can eventually catch fire at temperatures as low as 200 degrees. We have found many units are not installed improperly. You may want to install an access port to both check these clearances and monitor the unit’s condition from time to time. 


Many factory-built chimneys attract bird for nesting. We often have to remove a large amount of bird-nesting material from chimneys. It is important to get rid of this material because it can catch fire or block the air passageways between layers of metal chimney pipe, causing the chimney to overheat. Both of these situations can create house fires. 


Another consideration for pre-fabricated fireplace systems is that they don’t last forever. They wear out. We’ve seen particular models go out of production and manufacturers go out of business. Sometimes components needed to repair the unit are no longer available. 


No matter what type you have, our experts at A Sweep Across the Bay in Tampa Bay can help you keep your fireplace working properly and ensure the safety of your home and family. We can explain the anatomy of your fireplace, so you understand how to keep it in good shape. And our services are just a call away. Get in touch for immediate assistance.