Chimney liner installation for homes in Lake Mary Jane

Three situations where insulation helps

One manufacturer lists three situations where an approved insulation wrap enhances the performance and life of the chimney. We explain which, if any, apply to your chimney before you decide, and whether insulation in your case is a requirement or a recommendation.

Insulation also changes the space the liner needs, so the decision comes before the route is proven, not after.

• An installation that must meet UL 1777 at zero clearance to combustibles
• A chimney located on the outside of the house
• Appliances expected to produce low flue gas temperatures

What goes wrong with a poorly sized liner

Liner makers warn that improper sizing may lead to excessive condensation, creosote build-up and poor draft. Those are often the very complaints relining is meant to cure, so getting the size right is the point of the job.

We explain the sizing method we used and the source it came from, whether that is the appliance manual, the code's fireplace ratios or the fuel gas rules. If you already have a liner that was sized poorly, we show you the numbers that suggest it and what a correctly sized replacement would change.

Where the insulation wrap stops

When a liner is insulated with a wrap, one manufacturer has the insulation run from the bottom of the tee, including the tee cap, and stop about 3 inches below the crown to allow for vertical thermal expansion.

Details like that decide whether the liner can move freely as it heats and cools. A wrap that runs too high can bind at the top plate, and one that stops too low leaves part of the flue bare. We install to the instructions line by line and note the insulation on your records.

Permits and the local building department

Liner instructions note that building permits may be required before installation, and tell installers to contact local building and fire officials about inspection requirements. Local building inspectors have the final say over what they accept, whatever a national code or a product sheet says.

We check what applies to your relining job and tell you before scheduling, so a required inspection is planned rather than discovered. If a permit is needed, the estimate shows how it fits into the timeline.