Insulating liner

[1234567890]

I am working on removing my oil boiler and installing a woodstove in the basement. The chimney from the boiler currently has a stainless "forever flex" liner installed however there is no insulation. There is limited space in this chimney and a slight offset in the attic (2 story +walk up attic). One sweep looked at it said all I need to do is pour thermix down and I would be good (couple hundred $$) another sweep said it must be removed and reinstalled with insulation wrap (over a grand) over 2 grand if they cannot reuse the current liner. Chimney is an older brick one that does not appear to have any terracotta at the bottom (roof to steep to go up and poke around)

Any opinions/help would be great!

(mods if this is in the wrong section please move it)

 

[stoveguy13]

If there is no clay liner then it needs to be insulated you may be able to use a pour in mix but not knowing how much space you have around the liner you may not be able to get the proper insulation value if it is to small of a space outside the liner.

 

[webby3650]

Also, if there is limited space the insulation can get hung up in there so it is not very effect. I would pull it and wrap it if there is enough room.

 

[1234567890]

So if there is enough space up top (1 inch on all sides) how do you keep the proper spacing down the chimney if you install thermix?
Thanks for all your help to this newbee.

 

[stoveguy13]

the installer will need to make sure the liner is tight and even in the chimney and a block off at the bottom