The liner is damaged or missing

What has probably happened

• Age — many older houses have unlined chimneys or clay tiles that have cracked.
• A previous chimney fire, which cracks clay tiles almost every time.
• Water damage breaking down mortar joints between tiles.
• A new appliance vented into a flue that is the wrong size or material for it.
• Converting to gas without relining, which leaves acidic condensate attacking the masonry.

What the technician does

• A camera inspection first, because nobody should be told they need relining without being shown why.
• Stainless steel liner sized to the appliance and insulated where required.
• Cast-in-place lining where that is the appropriate repair.
• The appliance and flue matched properly — size, material and termination.
• Cap and crown addressed at the same time, since water is what destroyed the last one.

Questions people ask

How do I know if I really need it?

Ask to see the camera footage, and ask what specifically you are looking at. A cracked tile, a gap at a joint or a missing section is visible and explainable, and a second opinion is always reasonable on a job this size.

We are converting to a gas insert. Does it need relining?

Usually yes. Gas produces acidic condensate that attacks masonry and older flues are generally too large for a modern appliance, which makes it worse. The manufacturer's instructions will normally require a correctly sized liner.

Is stainless steel the only option?

It is the most common for a repair. Cast-in-place is used for badly deteriorated masonry chimneys. Which one suits depends on the chimney and the appliance.