Chimney flue liner installation in Azalea Park

Factory-built units listed for masonry chimneys

Factory-built chimneys or chimney units listed for installation within masonry chimneys are also accepted by the residential code. These are complete manufactured systems rather than a flexible liner alone, and their listing sets the clearances, the parts and the way they are supported.

We raise this route when a chimney's shape, its height or an appliance's needs point toward it, and we explain how it differs in plain terms before you choose. The estimate names the product either way, so there is no doubt about which system your chimney received.

Offsets and changes in direction

Chimney construction and offsets can change the size of the passage inside, sometimes well below the top. A flue that looks generous from the roof may narrow where it bends toward the fireplace or around framing.

The residential code also limits how far a masonry chimney with a clay liner may offset. We map the route, note any offset and plan a liner that passes it without crushing or kinking. A liner that has been forced around a tight bend is a liner that has lost area, and we would rather tell you about the bend now.

Liner size starts with the appliance outlet

For a stove or similar appliance, one liner maker says the liner should match the appliance's flue outlet, or follow the size the appliance manufacturer specifies. We read that size from the appliance and its manual, not from the old flue.

If the manual allows a different size, we explain why the proposal follows it and where in the manual the figure comes from. An old flue sized for a fireplace or a previous appliance tells us very little about what the current appliance needs, which is why we never copy its size.

What a relining estimate should list

Our written relining estimates list each part of the job, so you can compare them fairly with any other proposal. If a line is missing from a quote you received elsewhere, it is worth asking whether that part was left out or simply not written down.

• The liner product, diameter and length
• Insulation, and whether it is required or optional
• Top plate, liner cap and any extension
• The tee, adapter or other base connection
• Cleaning, tile removal and other preparation
• Separate lines for crown or masonry repairs