Is it really a Prefabricated fireplace system?
The first order of business is to determine if your fireplace is prefab or masonry. You can identify which type of fireplace you have by looking up with a flashlight toward the damper area from inside the home – wear safety glasses to avoid dust and particles! A factory-built fireplace will have a round damper and a round pipe, usually 7-11” in internal diameter. The damper plate on a masonry fireplace is usually rectangular, and approx. 6” x 24”. You may also be able to ID your fireplace by looking at the exterior of your home. A masonry fireplace will should have an orange clay liner, which is often visible at the chimney top – from outside the home. The two pictures show a typical prefab fireplace inside box and cap/termination. Another hint is to look at the outdoor enclosure around your fireplace and chimney. If it is covered with siding like the rest of the home, you almost definitely have a prefab. If, on the other hand, the exterior is solid brick which extends down to the ground, it is probably a masonry chimney. Another hint is the presence of large visible louvers and black metal facing on the front of the fireplace opening – this usually means a prefab. If in doubt, have a pro check it out for you – they can also advise you on the safety aspect of any upgrades you may have planned. The panels inside of the firebox are called refractory panels. These get cracked and beat up by heavy pieces of firewood being thrown (as opposed to gently placed…) into the firebox. They can also get cracked by over-firing of the system (building a fire that is too large for the system to handle. Refractory panels can be replaced. A damper can be replaced with a damper that is mounted on top of the smoke stack. The chimney cap on top of the smoke stack can be replaced. But when should the entire system be replaced? Stay tuned.