Loose chimney insulation - not set in place. Is it possible?

[joshuaviktor]

I am about to buy a ss liner for a chimney. I want to insulate as much of it as I can. The blankets are expensive, and I don't want to set a concrete style insulation in place, as my chimneys are historic (predate USA). Is there a material (perlite, vermiculite, something) that I can just pour in, and leave it loose?

Anyone?

Joshua

 

[webbie]

I am about to buy a ss liner for a chimney. I want to insulate as much of it as I can. The blankets are expensive, and I don't want to set a concrete style insulation in place, as my chimneys are historic (predate USA). Is there a material (perlite, vermiculite, something) that I can just pour in, and leave it loose?

Anyone?

Joshua

I once did one with vermiculite - and then was called back when it was running out of a TINY hole - it was also running INTO the chimney liner through tiny seams. So I would not suggest a roll your own.

Hate to say it, but I'd rather see no insulation (assuming pipe is sealed well at bottom and top) than see something that makes you rip the entire job out.

There may be some materials made for this now, but make certain the particle size is large!

 

[joshuaviktor]

how big is perlite grains? They make the expanded perlite that looks a bit bigger, yes?

 

[elkimmeg]

Josh I agree with Craig run the stove with the liner first. If all works ok forget the insulation.
If planning to pour it that can be done at a later date

 

[joshuaviktor]

MAkes sense. I'll do it.

 

[thechimneysweep]

Back in the '80s, we used to pour vermiculite in the flue cavity around the stainless liner to provide insulation, until one of our liner suppliers told us not to. Their explanation was that the vermiculite created tiny extra-insulated spots where the granules actually came in contact with the liner, each surrounded by less-insulated spots where the spaces between the particles were. They claimed that this heat differential caused the nickel content in 300-series stainless to migrate either towards or away from the tiny hot spots (I can't remember which), and this phenomenon would drastically shorten the lifespan of the stainless. At any rate, the bottom line was that the company wouldn't honor their warranty if a liner installed with vermiculite insulation failed.