FLEXIBLE LINER INSULATION
Insulating flues improve the draw.
When do we need to insulate a chimney liner?
- When the chimney is exposed on an outside wall;
- When the stack is particularly tall or;
- When the flue is of a large diameter.
Insulated liners keep the flue gases warmer, increase the upward speed of those gases and help prevent condensation.
Otherwise, it is not necessary. The air between the liner and the flue will insulate the liner.
Installing with chimney wrap:
Instead of feeding the flue down the chimney, you haul it up the chimney. The person at the top has to have a very secure platform (e.g. scaffolding). A cherry picker might work but add the liner and wrap weight to the maximum allowed by the cherry picker.
Vermiculite (Micafil) is supplied in bags. It is very light and will be taken by the wind easily.
Vermiculite cannot catch fire and is used to insulate chimney liners.
Vermiculite is only suitable for chimneys with a few inches of air gap.