Finally got around to insulating my fireplace

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mellow

Resident Stove Connoisseur
Jan 19, 2008
5,851
Salisbury, MD
Used Roxul R-15.
 

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I have not tried a fire yet, still not cold enough here, but this has already cut down alot on the drafts even with a block off plate with the chimney on the exterior alot of the heat was sucked up by the bricks. The insert touches the Roxul on the sides only, back has about 5 inches air space and top has 10" air space. I made sure the intakes for the secondary air on the sides are not blocked. My insert is hooked up to a UPS for possible power outages, that will last me about 6-8 hours on full blast longer if I turn it down, so power going out overnight and it overheating will not be an issue.
 
I would spray those batts with stove paint to lock the fibers. Just a light coating. It will keep fibers from getting all over the house.
 
You'll see loads of fibers laying all over... at night shine you brightest flashlight.
 
Thanks for the suggestion, but this material does not off gas, as soon as you put high temp paint on it you have introduced chemicals and off gassing.

I will keep an eye out to see if fibers are being sucked into the secondary air intakes, if it is I will have to fashion some sort of filter to put over them.
 
What capacity UPS are you using? I have an APC SmartUPS 1400 and wonder how long it could power the twin fans on an Osburn 2000 insert? I'd like to get at least 6 hours for an overnight burn when power is lost and the generator is turned off. After storms Irene and Alfred we lost power for 8 days combined.
 
Was the insulation approved by SBI or Flame? Flame warns about makeshift installations in the manual. That's why I ask. If uncertain, PM FyreBug, he works for SBI.
 
mellow said:
Thanks for the suggestion, but this material does not off gas, as soon as you put high temp paint on it you have introduced chemicals and off gassing.

I will keep an eye out to see if fibers are being sucked into the secondary air intakes, if it is I will have to fashion some sort of filter to put over them.

The whole stove is painted with stove paint. It will only outgas for a short while.
 
That Roxul is GREAT stuff. It's what insulates my hot tub. The heater never runs unless we're in it and the cover is off! Good choice! :-D
 
I think I'd have a metal shop (or do it yourself if you have the means) make a sheet metal surround to go in-front of that insulation and hide it / keep it in place if there is a risk of it coming down on the stove.

Unless of course the cover is off this. I think the last time this was mentioned, I believed the OP was wanting to actually cover the insert itself w/ the stuff.

pen
 
Why insulate the brick in your fireplace? So much heat radiates back into the room from it. The block off plate is a great idea but whats the point in keeping heat between you and the outer wall? There WILL in fact be fibers/dust coming from that batting. Thats what it is, fibers, and they arent adhered. Good luck.
 
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kallsop said:
What capacity UPS are you using? I have an APC SmartUPS 1400 and wonder how long it could power the twin fans on an Osburn 2000 insert? I'd like to get at least 6 hours for an overnight burn when power is lost and the generator is turned off. After storms Irene and Alfred we lost power for 8 days combined.

You can get a deep cycle marine 12V battery and a 12VDC to 115VAC converter (like the car ones), this should last much longer than most of the standard UPS's.


That looks like an excellent idea/execution with the insulation... I will keep an eye on this thread to see what others say. By insulating the fire box fireplace you are keeping the stove hotter, so I predict three of the following scenarios.

1) You would be able to run the fans on a higher speed during low burns, therefore spilling more heat into the room.
2) By keeping the stove temp higher you can close the air intake more, therefore slowing the burn and saving on wood.
3) I would think you would increase the efficiency of the stove as well, less heat getting lost by heating the big mass of bricks.

Let us know what is the outcome. please.
 
Loco Gringo said:
Why insulate the brick in your fireplace? So much heat radiates back into the room from it. The block off plate is a great idea but whats the point in keeping heat between you and the outer wall? There WILL in fact be fibers/dust coming from that batting. Thats what it is, fibers, and they arent adhered. Good luck.

I think I’m with you on this one. The fireplace “firebrick†could be considered an interior wall if you look at it. Behind the firebrick is another course of mortar and brick. So the heat absorbs into the firebrick and like you said, radiates back into the fireplace. Most of the heat will rise and hit the blockoff. From there, the heat will stay resident in the fireplace warming up the fireplace brick face and some will bellow out between the surround edges.
 
I guess you can say I have a different setup when it comes to exterior chimneys, I had to cut out my smoke shelf due to it rusting and falling apart, so that let heat go right to the exterior bricks. With this setup it is now fully enveloped.

As to fibers the surround is on at all times so that should block all transfer of fibers to the inside of the house, secondary air inlets do not mix with the air circulated around the insert and go straight to the firebox, so that should be of little concern now that I think about it.

I have attached before and after pictures from my clean out door, showing the space is now fully insulated.
 

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I just finished up insulating my wood framed chase with the Roxul as well.....I am not drywalling it so I was going to do what woodmiser said as well......high temp paint to lock the fibers down, he is 100% right about the little fibers coming off of the insulation...while Roxul is made from a type of stone (not sure what kind of stone) and is supposedly not harmful, it can be a lung/eye/skin irritant, so it is a good idea to try to somehow encapsulate that insulation, have you though about a tin sheild or something to keep the fibers covered up? I understand your concern about outgassing with the paint, but that would probably only be a one-time occurance....after it got warm once it shouldn't outgas again....keep us posted.....
 
I recently did the same to my stove... Didn't think about the fibers so I will take it out .. dont wanna clog up the stove
And definitely don't wanna endanger my 2 year old... Thanks for the heads up
 
I did this to my old Lopi last week, what a difference. Heat output is incredible, seems like it burns more efficient with less air as mentioned. I used the Roxul both as a block off plate and to insulate around the insert. I don't see how it would over fire it as it always has an air gap around the fire box with a natural draft circulating air.
 
Was cold enough last night to warrant firing up the insert, it does get to operating temp faster and the fan kicks on quicker, even with a small load. I did not do a full load in it to test an overnight burn, got started on it to late last night to get a good coal bed. Will report back later on that.