Factory-built fireplaces repaired with listed parts in Lake Cherokee

Alterations that take a fireplace out of its listing

Makers draw a clear line around changes to their units. One maker lists actions that void its warranty and that it disclaims responsibility for, including modification of the fireplace, its components, doors, air inlet system and damper control, and use of component parts it did not make or approve.

Past owners and past remodels sometimes altered a unit by trimming a panel, removing a shield or blocking an air inlet. We look for those changes, explain what each one affects and list what it takes to return the fireplace to its intended build.

Where the pipe passes through the roof

Where a metal chimney leaves the roof, a sloped metal cone is worked into the shingles and a storm collar wraps the pipe above it. One maker's manual calls for waterproof caulk around the collar's perimeter to seal it against the pipe.

The same manual warns against sealing the openings built into the rooftop cone. Split caulk, a collar that has slid down and a cone pulled loose by roof work are the leak points we find there, and each is repaired with listed parts.

Two chimneys in one chase

Some homes have two factory-built fireplaces venting through one chase. One maker suggests separating the terminations by at least 24 inches center to center and staggering their heights by 18 inches, to keep smoke from one drifting into the other.

When one fireplace smokes only while the other is burning, we look at the spacing at the top first. Changes there use the listed termination parts for each system.

• Center-to-center spacing
• Height difference between the tops
• Listed termination parts for each system

Discolored steel and scorched panels

Blue or straw coloring on steel and dark scorching on panels near the top of the firebox show where heat has been highest. Some color change is normal on a working fireplace, while heavy discoloration with warping points to fires hotter than the design.

We compare the marks with the rest of the unit and with the maker's list of overfiring signs. The finding shapes both the repair and the advice we give on how the fireplace is used afterward.