Cracked panels and worn fireplace parts fixed in Goldenrod

What holds up a factory-built chimney

Metal chimneys hang on supports and straps fastened to the house framing. Section R1005.5 says that where factory-built chimneys are supported by structural members such as joists and rafters, those members shall be designed to support the additional load.

Loose straps, missing fasteners and supports altered during other work let a chimney sag, which strains its joints. We check the supports we can reach and restore them with the maker's parts.

• Straps fastened to rafters or joists
• Supports above any offset
• Fasteners in place
• No sag at the joints

Clearances between the unit and the framing

Zero clearance describes a design, and the design still has clearances. One maker's model lists minimum clearances to combustibles at the back and sides of the fireplace, to the ceiling, in front of the opening and to the outer pipe of the chimney.

Remodels sometimes push framing, backer board or trim tighter than those figures. We compare what we can see with the manual for your model and list any clearance that needs correcting.

• Back and sides of the unit
• Ceiling above it
• Floor space in front of the opening
• Outer pipe of the chimney

Decorative tops on metal chimneys

Decorative shrouds dress up the top of a metal chimney. Sections R1004.3 and R1005.2 of the residential code permit a shroud at the top of a factory-built chimney only if it carries a listing and label for that exact system and goes on the way its maker instructs.

An unlisted shroud can trap heat and change how the chimney drafts. If your house has one, we check for its listing, and if there is none, we explain the options for replacing it with a listed top.

The smoke shield and the top of the firebox

The top of a factory-built firebox includes parts such as a smoke shield and an inner dome that guide smoke toward the damper and the flue. In one maker's parts list, both are marked as not field replaceable.

Damage there changes the conversation. We tell you what we see, which parts can be serviced and when the finding means the fireplace should be replaced as a whole.

• Smoke shield
• Inner dome
• Damper area above them
• What the parts list allows in the field