Liner Insulation

[Jodi]

I have an uninsulated m-flex stainless steel liner that was installed in an exterior chimney (10" X 10" terra-cotta lined). I would like to insulated the liner without removing it, but what is the best way. Can I use Everguard or TherMix pour down insulation or is there another pour down insulation? Which one is better and can it be installed dry? Also, will I be able to removing the liner at some point in the future with the pour down insulation?
Thank You.

 

[webbie]

Hello, Neighbor (I'm the original owner of your local stove shop there in Medford, Stoveworks)....but now moved to New England..

Removing the liner later is gonna be a tough nut. So the job is permanent or at least semi-permanent.

Thermix is installed slightly damp and not tamped down, as per their instructions:
Proper consistency is achieved when the material feels damp but is still granular (ca. 7 to 9 gallons of water/bag). Test: when a handful of properly moistened TherMix is squeezed hard, little or no water appears between the fingers.

During installation, correctly prepared TherMix pours like "loose fill". TherMix is distributed within the chimney cavity by vibrating the liner and does not have to (and should not) be tamped down. NOTE: Lining material manufacturers have their product specific instructions for this task. See CHIM-FLEX installation instructions for specific information.

By remembering your geometry and figuring the cubic area - then subtracting the stainless liner size - you should be able to figure out about how much you might need.

If you want to leave the option of the open fireplace, then I would suggest pulling the liner, wrapping it, and re-installing.

 

[Jodi]

Hey there,
Thanks for the reply. Original owner of Stoveworks...nice shop. I've been in there a few times since we moved to Shamong.

One more question...is there a loose fill mineral wool or ceramic insulation that can be used rather than a wrap? I'm trying to avoid pulling the liner if at all possible.
Thanks.

 

[pgmr]

I used vermiculite to insulate our flexible liner. Used it for 7-8 years until chimney was torn down during recent renovation work. I believe that perlite is actually a better choice - it doesn't absorb water as much. Perlite or vermiculite are available at garden centers for much less than the commercial insulating products. The loose fill products can work their way through any gaps around the pipe, so you'd need to get a good tight fit on your lower block off plate. http://www.perlite.net/ shows different grades of perlite. The coarse material would probably work best for insulating and wouldn't be able to get through small gaps in the block off plate.

 

[pgmr]

After purchasing some coarse perlite, I see that it, too, has a lot of small fines which could work past any small gaps between pipe and block off plate. Might be best to mix it with some portland cement and water (like Thermix) for the lowest portion (maybe the entire pour) to keep little stuff from constantly falling through. If you have an insert w/surround panels, you might not care, since it's not a lot of material, just noticeable if you don't.