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Vermiculite flue insulation

swvawethead Member Posts: 143
edited January 2017 in Radiant Heating
Installer poured multiple bags of vermiculite down the chimney as insulation around the stainless flue liner.
Even after a full day I was occasionally hearing the vermiculite slide down around the flue liner as if continuing to settle.
The installer said he would remove the liner cap to check for settling and top up the vermiculite as needed but hasn't done so.
I am assuming the insulation should be properly filled to the top of the chimney and liner cap - cover plate.
Boiler was commissioned Friday and I told the crew the second half of the project cost will be paid after the final inspection early in the week.
Installer has been very patient working with me sorting out installation details and I feel this should be followed up on.
I did not know anything about using vermiculite as liner insulation and want to make sure the project is properly completed before signing off.

Just out of curiosity looked up vermiculite and price is all over the scale (as high as $60/bag) and not sure if there is a specific type of vermiculite for this application.
They said the bags came from the HVAC supply house that deal only with contractor. (R.E. Michael).
This stuff not readily available retail?


    EBEBRATT-Ed Member Posts: 11,995
    As long as they fill and check it should be fine. Sounds like they know what they are doing.

    Not sure about the price or availability of vermiculite. In the old days I have herd that it contained asbestos.
  • Gordy
    Gordy Member Posts: 9,514
    Asbestos in vermiculite depended on which quarry it was mined from.
  • swvawethead
    swvawethead Member Posts: 143
    If I am not mistaken stuff produced since the 1990s should be asbestos free unless a bag dug out of an old pile of inventory is used. I sure hope not in our chimney.

    I just need them to return and check the level and top up and don't see why they wouldn't follow through without me holding up the second half of the payment.
    I can check the level myself but it just started snowing...
    I think the top cover plate/surround is tapcon screwed to the mortar top.
  • swvawethead
    swvawethead Member Posts: 143
    Anyway, if the coarse stuff is only available through a HVAC supply house they will run me out of there as soon as I set foot through the door so I will need to ask the installer to take care of it.