Cracked and open flue joints repaired in Hibiscus

Liners need support on every side

The code says flue liners shall be supported on all sides, and BIA Technical Note 19B says the first liner should be supported along its entire perimeter by masonry. A tile that loses its support can tip, slide or crack under the weight above it.

When a section has shifted, we look at what is holding it and whether the tiles above are resting on it. Loss of support usually makes a surface repair unsuitable, because the problem is the position of the tile, not only its face.

The yearly check NFPA 211 calls for

NFPA 211, the national standard for chimneys, fireplaces, vents and solid fuel-burning appliances, calls for a yearly inspection of each chimney, fireplace and vent to confirm it is sound, not clogged with deposits and at correct clearances, with cleaning, upkeep or repair if the inspection shows a need.

A yearly look is how flue damage tends to get caught early, while a repair is still small. If your chimney has gone longer than that, our free inspection is a good place to start, and it tells you whether the flue needs anything at all.

What a flue repair estimate should list

A flue repair estimate should be specific enough to compare with another quote. Vague lines such as repair liner leave you unable to tell what is being fixed.

Ours list each item below. Book within 72 hours after the inspection and 10% off is printed right on the estimate.

• Sections of the flue included in the repair
• The method and the named product or material
• Cleaning and preparation before the repair
• Related work such as a cap, crown or cleanout cover
• Curing time and when the fireplace can be used
• Anything that could not be seen or confirmed

Weather, curing and scheduling

Mortars and repair products need the right conditions to cure. Heavy rain or high humidity can interfere with some products, especially at the top of the flue.

We schedule around the forecast and follow each product maker's curing instructions. If weather delays the work, we let you know and reschedule rather than rushing a repair that needs time to set. A coating applied inside a damp flue may not bond, and fresh mortar at the top can wash out in a downpour. Waiting a day for dry conditions costs far less than repeating the repair.