What is the purpose of Insulation?
There are many reasons to use insulation. One is to keep the heat away from the home and keep the heat in the liner. When you keep the heat in the liner it helps keep the smoke warm. When you keep the smoke warm it keeps rising out of the chimney and does not stay in the chimney and create creosote.
So when you insulate the liner you are reducing your creosote buildup which then reduces the chimney fire risk also. It increases the draft which makes for a much more consistent burn.
There are two types of common insulating methods.
The first type is a pour in vermiculite and concrete insulation mixture that is poured down the chimney and dries in place. This pour down mixture is an easy answer to reducing condensation and stabilizing your draft. It is also the best insulating solution for those tight clearance chimneys. More on Insulation mix
The other is a 2100 degree blanket. This type of insulating is a safer alternative to the ceramic wool blankets because of its accelerated rate of solubility in body fluids and its low bile persistence.
In order to insulate with this type of blanket you must wrap the liner before it is inserted into the chimney. You start by laying the blanket out on a flat surface. The stainless steel liner is then placed in the center. Wrap the blanket around the liner and temporarily hold it in place with the spray adhesive. This step is optional but helps in keeping the blanket in place for the next step.
A wire mesh sock is then pulled up over the liner which holds the blanket in place during installation. A stainless locking wire is then spiraled around the mesh for added support.
Now, with the locking wire secured at each end of the liner it is ready to be inserted into the top of the chimney.