Does My Chimney Need a Liner? What Stuart Homeowners Should Know

What a Liner Does Inside the Chimney

Picture the chimney as two things: the masonry you see from the yard and the flue inside it. The liner is the wall of that flue. It contains the heat of the fire so the brick and the wood framing around the chimney do not get hot enough to char. It holds the moisture and acids that combustion leaves behind so they do not eat into the mortar. And it gives the smoke a smooth passage of the right size so the fireplace draws well.

Clay tile is the most familiar liner in older masonry chimneys. Stainless steel liners are the usual choice when a chimney is relined, and some flues are relined with a cast-in-place cement mix. Factory-built fireplaces have their own listed metal chimney pipe, which acts as the liner.

Is a Chimney Liner Required?

In practice, yes, for any chimney you burn in. NFPA 211, the standard for chimneys, fireplaces and vents, calls for a flue liner in masonry chimneys, and the Florida Building Code's chimney provisions follow the same idea. The exact requirement for your home depends on when it was built and what the chimney serves, which is why we look before giving an answer.

When a fuel-burning appliance such as a wood insert or a gas insert is connected to a chimney, its maker's instructions almost always call for a liner sized to its outlet. That is often why homeowners ask whether their chimney needs a liner.

Signs Your Liner Is Missing or Damaged

A chimney without liner protection may look fine from the room, because the damage happens out of sight. To know for sure, the flue has to be checked from inside with a strong light during an inspection or sweep.

• Pieces of clay tile on the smoke shelf or in the firebox
• Cracks or open joints seen during a sweep
• A smoke smell in rooms beside the chimney
• Water or dark stains running down the inside of the flue
• A past chimney fire, even a small one

What Relining Involves

Relining starts with measuring the flue and the fireplace opening or appliance outlet, because the liner must be sized to what it serves. A stainless steel liner is fed down from the roof, connected at the bottom, and fitted with a top plate and cap. Insulation is added where the flue needs it to stay warm or to meet clearances. Many relining jobs are finished in a day.

Repairing clay tiles in place is sometimes possible when the damage is limited. When tiles are broken through or missing, a new liner is the safer choice.

A Stuart Homeowner's Checklist

• Burning wood or gas through a masonry chimney? Ask when the flue was last inspected.
• Adding an insert? Plan for a liner sized to it.
• Seeing tile pieces or smelling smoke next door to the fireplace? Stop using it until the flue is checked.
• Buying a home with a fireplace? Include the flue in the inspection.