Micore and/or Roxul Rockboard for damper block-off?

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NYSB

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Mar 30, 2015
45
New York
I have an insert (Regency CI2600) installed in our masonry fireplace, which is on an outside wall with exterior brick chimney. It works great, but I suppose it could always be better. Other than the floor of the old fireplace, with which the stove is sitting on, there is at least 2-3" of clearance between the exterior of the insert and the interior walls of the fireplace.

I'm thinking of lining the interior of the fireplace with Micore to help maintain high efficiency - assuming I get the "OK" from Regency tech support.... I would do this with the stove in place. I could envision making a sort of frame with angle iron to hold the micore panels in place. I also have Roxul 2" acoustic insulation panels which I could use as well.

By the way, I was 'experimenting' with a chunk of roxul to restrict air flow from the boost air manifold in the stove and ended up leaving it the firebox for a couple of weeks of continuous burning. Took it out and it looked totally unchanged. So I'm pretty sure it's as fireproof as they claim...
 
I would simple hold the micore in place with tapcons and large washers. It is very light and won't need a lot to hold it in place. 3-4 screws + washers should do it.
 
Roxul acoustic is not the same stuff as their thermal insulation. Don't use those leftovers. If you decide to use Roxul, buy a bundle of the stuff they make for thermal insulation.
 
Oldman47 said:
Roxul acoustic is not the same stuff as their thermal insulation. Don't use those leftovers. If you decide to use Roxul, buy a bundle of the stuff they make for thermal insulation.
Click to expand...


Are you sure? According to their website, the Roxul Rockboard 60, which is what I have, has exactly the same specs as their other products - non-combustible, melting point > 2000 degrees, non-corrosive, does not support growth of mold/fungi, etc... On their FAQ list, they say there is no off-gassing from any Roxul products, including the Rockboard. Unless the use additives or binders that they do not admit to, it would appear to be the same product which is manufacturered to different densities/thickness.

I plan to obtain some of the Roxul batting insulation as well, to stuff up into the damper area above the proposed block-off plate. The reason I plan to use the rockboard inside the masonry firebox is that it is very stiff and will hold its shape. This will make easy to form a "box" of insulation between the inside wall of the fireplace and the outside of the stove. All of this is contingent on how much room there is. The rockboard is 2" thick, while the micore is 1". Most likely I will use a single layer of micore on the back and sides, roxul batting stuffed up into the damper area (as much as I can get up there), and roxul rockboard to for the block-off plate. I will be doing this with the insert still in place so we shall see how it works out.

Thoughts?
 
I strongly recomend just pulling the insert you will spend way more time and agrivation with it in there and probably will not get it done any where near as well. I know i would pull it out if it was me
 
bholler said:
I strongly recomend just pulling the insert you will spend way more time and agrivation with it in there and probably will not get it done any where near as well. I know i would pull it out if it was me
Click to expand...


You're probably right, of course, but it's a pretty large opening with quite a bit of room between the top of the insert firebox and the fireplace lintel, and 4-6" on either side. So I think it's do-able. If it turns out to be impossible I'll recruit four friends who feel like lifting 500+ pounds... I'll report back with pictures of course.

I've been working it out in my head while I've been splitting/stacking next year's wood...
 
NYSB said:
Are you sure? According to their website, the Roxul Rockboard 60, which is what I have, has exactly the same specs as their other products - non-combustible, melting point > 2000 degrees, non-corrosive, does not support growth of mold/fungi, etc... On their FAQ list, they say there is no off-gassing from any Roxul products, including the Rockboard. Unless the use additives or binders that they do not admit to, it would appear to be the same product which is manufacturered to different densities/thickness.

I plan to obtain some of the Roxul batting insulation as well, to stuff up into the damper area above the proposed block-off plate. The reason I plan to use the rockboard inside the masonry firebox is that it is very stiff and will hold its shape. This will make easy to form a "box" of insulation between the inside wall of the fireplace and the outside of the stove. All of this is contingent on how much room there is. The rockboard is 2" thick, while the micore is 1". Most likely I will use a single layer of micore on the back and sides, roxul batting stuffed up into the damper area (as much as I can get up there), and roxul rockboard to for the block-off plate. I will be doing this with the insert still in place so we shall see how it works out.

Thoughts?
Click to expand...
I am certain that the Roxul made for sound deadening and the Roxul made as thermal insulation are not the same. The melting point may well be the same but the way the batts are made is different. Sound deadening takes a different material arrangement to thermal insulation. It is not just true of Roxul brand. Lots of insulation manufacturers make separate product lines for sound and for thermal insulation because the needs of each product are really different.
 
Oldman47 said:
I am certain that the Roxul made for sound deadening and the Roxul made as thermal insulation are not the same. The melting point may well be the same but the way the batts are made is different. Sound deadening takes a different material arrangement to thermal insulation. It is not just true of Roxul brand. Lots of insulation manufacturers make separate product lines for sound and for thermal insulation because the needs of each product are really different.
Click to expand...

"The difference between ROXUL COMFORTBATT® and ROXUL SAFE‘n’SOUND® is density (weight) and batt size. ROXUL SAFE‘n’SOUND® is denser than COMFORTBATT® and is manufactured to an approximate 3 inch thickness. "
 
Roxul rock board is advertized as thermal and acoustic insulation and it is rated to 2000 degrees it is perfectly fine to use in this application.
 
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