Every century or so an inventor comes into our world and solves one of the world’s problems. This century, the chimney industry was the beneficiary of a very clever invention that provides a slip cast system for repairing the innermost portion of failed chimneys. Chimney contractors, such as Midtown Chimney Sweeps, are grateful to the inventors of HeatShield® Cerfractory® Flue Sealant. This webpage will provide an overview of the Heatshield repair method.
According to NFPA 211, a flue (the innermost portion of the chimney that comes into direct contact with the byproducts of combustion) has a specified job. Furthermore, NFPA 211 describes what failure is.
14.9* Damaged or Deteriorated Liners. If the flue liner in a chimney has softened, cracked, or otherwise deteriorated so that it no longer has the continued ability to contain the products of combustion (i.e., heat, moisture, creosote, and flue gases), the liner shall be either removed and replaced, repaired, or relined with a listed liner system or other approved material that will resist corrosion, softening, or cracking from flue gases at temperatures appropriate to the class of chimney service.
What causes this failure? Rainwater coming down the inside of a chimney, soaking into the soft red clay flue tiles, followed by heat from a fire. Freezing and thawing of the flue tiles and other surrounding masonry materials. Acidic moisture from sulfur producing heater appliances vented into the flue. Spalling caused by general deterioration and softening and cracking of clay flue tiles.
The difficulty of repairing these flues is their location. They are not accessible, so Midtown Chimney Sweep technicians who are certified HeatShield® Cerfractory® Flue Sealant installers must use specialized equipment to access these areas. The flue of a standard masonry fireplace is approximately 13″ x 13″ and half way up a 25 foot chimney there may be a cracked flue tile, or missing mortar in the flue tile joint that needs to be repaired. How can someone ever reach in there and repair it? Midtown Chimney Sweeps uses specialized tools and equipment to reach the inaccessible areas of the flue and coat the entire surface or pack those missing mortar joints.
The product called Heatshield was first created in Europe over 20 years ago, and HeatShield’s® Cerfractory® technology is now a complex hybrid (ceramic/refractory) coating and is proven effective both in use and by independent lab testing.
As a repair, it’s been proven to withstand moisture, corrosive flue gases with sulfuric compounds, and high flue gas temperatures in up to 2900°F! It’s rated a super duty refractory mortar per American Society for Testing and Materials (ASTM) C199. It surpasses requirements of both the National Fire Prevention Association (NFPA) and International Residential Code (IRC) which require only a “Medium-Duty” refractory mortar for use in fireplaces and chimneys. We at Midtown Chimney Sweeps is excited to provide you the best in chimney flue repair methods! To learn more about HeatShield’s® extensive testing, listing, and certification visit HeatShield® technology and testing.
Independent HeatShield® Installers are carefully selected based on their industry certifications and experience. Trained with factory education and specially designed application tools, your HeatShield professional can expertly repair your chimney. Special video cameras are used to verify completed repairs. Call Midtown Chimney today to see if we have a trained professional in your area!