Cracked panels and worn fireplace parts fixed in Aloma

The chimney is part of the fireplace's listing

A factory-built fireplace is tested with a specific chimney. Section R1005.4 says chimneys for use with factory-built fireplaces shall comply with UL 127, the same standard as the fireplace, and R1005.1 has factory-built chimneys listed and labeled, then installed and finished at the top as their maker directs.

That makes the metal chimney a matched part of the system. Repairs to pipe sections, supports or the top of the chimney use the components the fireplace's manual names.

When the house pulls against the fireplace

A fireplace needs replacement air for what goes up the chimney. One maker's manual explains that exhaust fans, range hoods, clothes dryers and other household equipment can create negative pressure in the room and pull combustion by-products back into the home.

The same manual suggests opening a nearby window with the fire burning to see whether the smoking stops. If it does, the fix lies in the house air, and we explain the options before touching the fireplace.

• Exhaust fans
• Range hoods
• Clothes dryers
• Air handling near the fireplace

Why a prefab fireplace smokes

One maker's troubleshooting guide lists the usual reasons a fireplace smokes, including negative pressure in the house, blowers such as a range hood, wet wood, a dirty or blocked chimney and a chimney that is too short.

We work through that list in order, starting with the easy checks. Many smoking complaints end with a cleaner flue or a change in the house, and only some need parts.

• Negative pressure in the house
• A range hood or other blower running
• Wet or unseasoned wood
• A dirty or blocked chimney
• A chimney that is too short

Prefab fireplaces in condominiums and townhomes

In condominiums and townhomes, the chimney of a factory-built fireplace can run through a shared attic or chase, and the association may have rules about roof and exterior work.

We suggest checking with the association before work that reaches the roof or a shared chase. Inside your unit, the repair follows the fireplace's listing, and our written scope gives the association a clear description of the work.

• Association rules checked first
• A written scope for the association
• Roof and shared chase work coordinated