A furnace or boiler flue is relatively inexpensive to reline, but it’s extremely costly to reline a fireplace flue because the existing terracotta flue tiles must be removed in order to fit a new liner down the chimney. Other factors like insulating the new chimney liner for wood burners also increase the cost. While some cracked flue tiles can only be repaired by relining the chimney, Chimney Pros and Kleen Ducts can repair many defective fireplace flues for a fraction of the cost of relining the flue with FireGuard.

Masonry chimney flues typically exhibit three distinct types of damage that make the chimney unsafe to use:
• CRACKED OR BROKEN FLUE TILES: A cracked tile can be caused by a variety of factors from the thermal stress of a chimney fire or a lightning strike to a defect when the tile was fired. This problem is typically fixecd by relining the flue with a stainless steel liner, but in some cases we can re-surface the tiles with FireGuard for a fraction of the cost of relining the chimney.

• SPALLED OR DELAMINATED FLUE TILES: Usually caused by the corrosive effects of oil soot. This problem is best remedied by relining the flue.

• OPEN MORTAR JOINTS BETWEEN FLUE TILES: This is the most common type of flue damage we encounter. It results when the chimney’s builder uses ordinary mortar, instead of heat resistant refractory mortar, to bond the flue tiles. Fortunately, we are able to economically correct this problem with FireGuard.

The FireGuard system uses a vibrating applicator that is winched through the flue to force a special heat resistant ceramic material into open mortar joints. We are also able to repair some cracked flue tiles with a special applicator that resurfaces the entire flue tile. The FireGuard material has a service temperature that far exceeds the requirements for residential chimney. It creates a solid, smooth, water and acid resistant surface.

While relining the flue with corrugated stainless steel remains our preferred method of repairing a furnace or boiler flue, the FireGuard system can’t be beat for an economical solution when open mortar joints or cracked flue tiles in a fireplace flue require repair.