Young Brunette Girl Wearing Black Lingerie At The Fireplace

• Reinforced concrete chimneys. Fundamental flaws (the difference in thermal expansion rates between steel rebar and concrete which caused the chimney flues to crack when heated) bankrupted the US manufacturers and obsoleted the technique. This is evidenced by vertical cracks on the exterior of the chimney.
• Metal-lined flue: Double or triple walled metal pipe running up inside a new or existing wood framed or masonry chase
Newly constructed flues may feature a chase cover, a cap, and a spark arrestor at the top to keep small animals out and sparks from exiting the chimney cavity.