Flue liner replacement for South Apopka homes

After a chimney fire or a damaging storm

A building or chimney fire, a weather event or any incident likely to have damaged the chimney is another NFPA 211 reason for a closer inspection. Intense heat can crack clay tile and open its joints, and a storm can shift the top of a chimney or damage its cap.

Stop using the fireplace until the flue has been checked, and let us know what happened, so the inspection can focus on the damage most likely to be there. Relining is discussed only after that inspection, based on what it actually found in the flue.

Sizing a liner for an open fireplace

An open fireplace is sized by its opening. Option 1 of section R1003.15.1 calls for a round flue of at least one-twelfth of the fireplace opening area, a square flue of at least one-tenth, and a rectangular flue with a ratio of 2 to 1 or more of at least one-eighth.

We measure the opening, apply the rule that fits the proposed liner shape and write the numbers down for you. A liner that is too small for a large opening can leave smoke at the front of the fireplace, so the opening size decides the liner as much as the chimney does.

Why a non-conforming chimney needs insulation

One manufacturer explains that UL 1777 requires insulation where a chimney does not conform to code, for example one with zero clearance to combustibles or another defect. A chimney that meets NFPA 211 construction requirements may not need it.

That is why we look at how the chimney was built before deciding on insulation, instead of adding it by default or leaving it out to lower a price.

Questions worth asking before you approve relining

A sound relining proposal should answer each of these clearly. If one of them gets a vague answer, ask again, since each one affects how the liner performs or what the job includes.

• What finding makes the current lining unsuitable?
• Which listed product is proposed, and at what size?
• Is insulation required, or only recommended?
• What preparation happens before the liner goes in?
• Which old parts stay, and which come out?
• Which separate repairs, if any, are recommended?