Finally got around to insulating my fireplace

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I would still do a block off even on an internal chimney, I just wouldn't worry as much about insulating the firebox, but I still believe that insulating the firebox helps keep the heat where it needs to be in either an exterior or interior fireplace.

At a minimum pulling the surround and stuffing the damper throat with Roxul will be better than doing nothing.
 
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mellow said:
I would still do a block off even on an internal chimney, I just wouldn't worry as much about insulating the firebox, but I still believe that insulating the firebox helps keep the heat where it needs to be in either an exterior or interior fireplace.

At a minimum pulling the surround and stuffing the damper throat with Roxul will be better than doing nothing.
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Thanks, Mellow...

Because I haven't pulled the surround (and wasn't around for install), I don't know if there is a block-off plate. Do you know if it standard install procedure to put in a block-off plate or do you think it's possible that I just have a stainless flue running up my chimney with an opening around it?
 
Your wife would do that for you? You're a lucky man. ;lol
 
HappyCamperMan said:
I haven't pulled the surround (and wasn't around for install),
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If you didn't ask for a block-off or insulated liner the chances you got either are pretty slim. Typically installers will put some insulation up top between the liner and the clay tile and that's about it.

I agree with others that insulating the fire box is less critical on an interior install the reasoning being that any heat absorption by the masonry will eventually be given back to the house unlike an exterior where the heat goes out to atmosphere.

I also agree that I would pull the surround and insulate the damper area and smoke shelf w/ Roxul to keep as much heat in the house rather than sending it up the chimney and to keep the liner as hot as possible. Especially true since they may not have insulated up top as well as you might like and heat lost from there would be wasted.

With any luck you'll have room to do this with the insert in place. A metal block off would be even better and if you have the room can be installed in two pieces also w/o removing the actual insert.
 
Block off plate is important in both cases. It prevents hot air from escaping outside. The insulation of firebox very important if it is exterior chimney and not so if it's internal chimney. The stone going to absorb energy and give it away slowly hours after. If you want quick heat output from your insert you can insulate your firebox as much as you can and use blower on full speed . If you burn on a regular basis you might be better off with blower on low and not so much roxul around. I put some in my internal firebox and it's still absorbs a lot of heat, but I've noticed that house stays warmer long after fire is gone vs other sources of heat.
 
I asked in another thread but I'll ask here too, how would you insulate the top of your block off plate if you only had access from inside/under the fireplace?

Also is there an insulation difference of one cement board over another? I tried to read the difference and all I found out is people like certain brands differently and its great in a bathroom if you put a vapor barrier up; so nothing really about the insulating or heat radiating properties.
 
Well I don't have any insert yet so I won't have to pull it out. I'm going to fabricate the fireplace liner after I can get exact measurements for the profile of the insert I'm going to install. I want to stuff the fireplace as much as possible.
 
Xtrl9 said:
Well I don't have any insert yet so I won't have to pull it out. I'm going to fabricate the fireplace liner after I can get exact measurements for the profile of the insert I'm going to install. I want to stuff the fireplace as much as possible.
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You want the stove there to do that. I have found it usually does not work out well fitting the liner and plate without the stove.
 
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I'm at that stage right now, with extra dura rock sitting around. Was it worth it in your opinion to do all of this? Not the block off plate, as I'm doing that for sure, but behind the stove, and on the sides?
 
I finally did this last week.

Cat temp 1250 when I went out side to 31*. Used my IR temp and got a base line on the brick of 29*. The area where my insert would be was reading about 34*. The chimney area above the roxul was reading about 55*. Last year when I would check the insert area was running in the 50s.

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Kinda funny story about this, when I insulated my fireplace and made my block off plate I cut the hole to have about 1/8th of clearance for the liner. Due to the angle of the dangle, it was like trying to bullseye a womp rat with a t-16. I ended up breaking my block off plate in the front so now one side hangs down some from the top of the firebox.
 
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Hey guys. I'm nearly through with my installation - can't wait to have the stove back in her. I'll post pictures tomorrow, maybe.

But I wanted to ask... Why did we use the durock in the fireplace? Is it for insulation purposes (in addition to the r-15 roxul my fireplace is filled with) or more for protection of the durock? What role does it primarily play?

I haven't really found that answer anywhere. Thanks for this thread. It really helped out.
 
brettdacosta said:
Hey guys. I'm nearly through with my installation - can't wait to have the stove back in her. I'll post pictures tomorrow, maybe.

But I wanted to ask... Why did we use the durock in the fireplace? Is it for insulation purposes (in addition to the r-15 roxul my fireplace is filled with) or more for protection of the durock? What role does it primarily play?

I haven't really found that answer anywhere. Thanks for this thread. It really helped out.
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I guess to hold Roxul in place , I didn’t use it
 
mellow said:
It holds back the fibers of the roxul but at the same time acts as an additional insulator, I got good results from using both but you are free to use one or the other in your install.
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I know this is an old post, but I am just about to start this same project. I am wondering, what I summation value does the Durock have? Isn’t it just like the brick? Just holds heat and passes it off somewhere? It’s not keeping the heat in is it? Or is it because it’s backed with Roxol that this concept works? I’m not questioning the idea, it’s obviously working for many of you. Just want to understand it before I go to the time and effort.
 
Bushels20 said:
I know this is an old post, but I am just about to start this same project. I am wondering, what I summation value does the Durock have? Isn’t it just like the brick? Just holds heat and passes it off somewhere? It’s not keeping the heat in is it? Or is it because it’s backed with Roxol that this concept works? I’m not questioning the idea, it’s obviously working for many of you. Just want to understand it before I go to the time and effort.
Click to expand...
Durock NexGen has some insulative property due to the pumice chips in it.
 
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