Masonry & Chimney Terminology
This list covers some of the most common terms, but there are many more specialized terms used in the masonry and chimney industry, particularly when dealing with different types of chimneys, materials, and repair techniques.
Structural Components:
Flue: The passage through which smoke and gases exit the chimney.
Chimney Cover: A stainless steel cover placed on top of the chimney with a roof-type cover and wire mesh on the sides to prevent water, debris, and animals from entering.
Crown or Cap: The top surface of the chimney that is designed to protect the masonry.
*Sometimes people will interchange the terms Crown & Cap or Cover. A Crown is usually masonry (concrete/mortar) while a Cap/Cover is usually metal.
Materials:
Firebrick: A special type of brick designed to withstand high temperatures.
Refractory Mortar: A type of heat-resistant mortar that is used for laying firebrick. Standard mortar is insufficient in a firebox and a common DIY mistake that can have disastrous results.
Flashing: Metal sheets that prevent water from entering where the chimney meets the roof. Damaged or faulty flashing is the #1 cause of leaks.
Stucco: A material used to cover and protect the exterior of a chimney.
Tuckpointing: The process of removing and replacing old deteriorating mortar with new mortar, also known as repointing.
Crown Repair: Fixing or replacing the chimney crown to prevent water damage.
Relining: Installing a new flue liner inside an existing chimney.
Creosote: A tar-like substance that builds up inside the flue and can become a fire hazard if not cleaned. Stage 1 is a flaky buildup, Stage 3 is a glazed soild.
Draft and Airflow:
Draft: The flow of air through the chimney, which is crucial for proper combustion.
Downdraft: A condition where air flows down the chimney instead of up, potentially causing smoke to enter the home.
Ventilation: The process of ensuring proper air movement through the chimney and fireplace.
Advanced Masonry Issues & Safety:
Efflorescence: A white, powdery deposit of salts often seen on the surface of concrete, brick, or stone. It occurs when water moves through the masonry and evaporates, leaving behind minerals. While often aesthetic, it usually indicates a moisture problem that needs investigation.
Spalling: The cracking, peeling, or chipping of a brick’s surface. This typically happens due to the freeze-thaw cycle, where moisture trapped inside the brick freezes and expands, forcing the face of the brick to pop off. If left untreated, it can lead to structural failure.
Smoke Chamber: The transitional area of a chimney located between the firebox and the flue. Its purpose is to funnel smoke and gases efficiently into the flue. A damaged or poorly parged (smoothed) smoke chamber is a common fire hazard and can significantly reduce the draft of your fireplace.
Don’t Let Small Issues Become Costly Repairs
Notice any of these issues with your chimney? From crumbling crowns to damaged, spalling bricks, I can provide thorough inspections and long-lasting repairs to keep your home safe and efficient.