Install advice needed

[Mechanized82]

Hello, I'm new here and new to wood burning and looking for a few bits of advice.

I have a fireplace that used to contain a firebox. Everything was rusted to oblivion so I removed the brick facing in order to remove the fire box. chimney looks to be in great shape. 6x10 terracotta liner. I just purchased a used quadrafire 3100i insert with a 6" Liner.

1. Should I Insulate the liner? I'm getting some mixed reviews. I see some say to insulate for a few reasons, and i've also been told not to, so the insert can get some air flow.

2. if I should insulate, what is the best way? seeing as how I don't have the clearance the whole way around the liner.

3. Should I seal up the ash pit underneath the fire place?

 

[bholler]

Hello, I'm new here and new to wood burning and looking for a few bits of advice.

I have a fireplace that used to contain a firebox. Everything was rusted to oblivion so I removed the brick facing in order to remove the fire box. chimney looks to be in great shape. 6x10 terracotta liner. I just purchased a used quadrafire 3100i insert with a 6" Liner.

1. Should I Insulate the liner? I'm getting some mixed reviews. I see some say to insulate for a few reasons, and i've also been told not to, so the insert can get some air flow.

2. if I should insulate, what is the best way? seeing as how I don't have the clearance the whole way around the liner.

3. Should I seal up the ash pit underneath the fire place?

Well first off why did you pull off the face? You made a whole lot more work for yourself. And yes you should insulate it either by removing the clay or ovalizing the liner so it fits with the insulation. Then make a plate to close off space around the liner.

 

[Mechanized82]

Thanks for the quick response.

Damper didn't move and had about a 2x3" space to fit a liner through. Also had no clue what was behind the firebox, was worried about potential combustibles. I've been remodeling my entire house so I'm used to this. Not afraid of a little work.

Ok, so that's what I've been reading. Is there any merit to being told to leave it without insulation? Will the unit get enough air flow from the house?

I was also told by an installer that I could just use a block off plate and stuff insulation down the two sides of the liner that have an air gap, pros and cons there having the liner touch the terracotta? The flue and surrounding masonry are in great shape, if that matters.

 

[bholler]

Thanks for the quick response.

Damper didn't move and had about a 2x3" space to fit a liner through. Also had no clue what was behind the firebox, was worried about potential combustibles. I've been remodeling my entire house so I'm used to this. Not afraid of a little work.

Ok, so that's what I've been reading. Is there any merit to being told to leave it without insulation? Will the unit get enough air flow from the house?

I was also told by an installer that I could just use a block off plate and stuff insulation down the two sides of the liner that have an air gap, pros and cons there having the liner touch the terracotta? The flue and surrounding masonry are in great shape, if that matters.

Does the masonry structure have the required clearances to combustibles? For an internal chimney you need 2" and external you need 1" from the outside of that masonry structure to any combusibles. If you dont have that you need an insulated liner. And yes technically you can connect it that way but it will not work as well as it should. And you will have to pull the stove and plate every year to clean.

You could have just cut that heatilator out without disturbing the face we do it all the time for rebuilds. You now have to make sure you have enough masonry left in your fireplace to be useable.

 

[kennyp2339]

Even if you have all the required clearances an insulated liner will keep flue gases much warmer, this will improve draft and reduce potential creosote formation by keeping the gases hot enough that they don't condensate in the chimney pipe.
A block off plate will help keep the heat that the insert produces from going up the flue, or being absorbed into the brick masonry.

 

[Mechanized82]

Does the masonry structure have the required clearances to combustibles? For an internal chimney you need 2" and external you need 1" from the outside of that masonry structure to any combusibles. If you dont have that you need an insulated liner. And yes technically you can connect it that way but it will not work as well as it should. And you will have to pull the stove and plate every year to clean.

You could have just cut that heatilator out without disturbing the face we do it all the time for rebuilds. You now have to make sure you have enough masonry left in your fireplace to be useable.

On top of the above mentioned, the face brick was cracked and bowing toward the living space. Upon demo I found that the straps embedded in the mortar had rusted through (improperly flashed and uncapped chimney led to everything in and around it rotting and rusting) and the face was no longer secured to the chimney. So i still think I made the right choice in demolishing the whole face. It didn't seem safe.

I've uploaded some pics so you can see what I'm working with. It's an outside chimney. So the wood framing you can see in the pictures is too close since its up against it? Is this a new code that must be followed because none of the wood surrounding the masonry looks like it ever got hot.

Even if you have all the required clearances an insulated liner will keep flue gases much warmer, this will improve draft and reduce potential creosote formation by keeping the gases hot enough that they don't condensate in the chimney pipe.
A block off plate will help keep the heat that the insert produces from going up the flue, or being absorbed into the brick masonry.

Yeah, my research keeps coming down to insulating and doing a block off plate. I guess I was just curious if there were any cons to this method or is it pretty much just an always do kind of thing?

 

[Ludlow]

How can a masonry chimney not touch the house?

 

[bholler]

On top of the above mentioned, the face brick was cracked and bowing toward the living space. Upon demo I found that the straps embedded in the mortar had rusted through (improperly flashed and uncapped chimney led to everything in and around it rotting and rusting) and the face was no longer secured to the chimney. So i still think I made the right choice in demolishing the whole face. It didn't seem safe.

I've uploaded some pics so you can see what I'm working with. It's an outside chimney. So the wood framing you can see in the pictures is too close since its up against it? Is this a new code that must be followed because none of the wood surrounding the masonry looks like it ever got hot.




Yeah, my research keeps coming down to insulating and doing a block off plate. I guess I was just curious if there were any cons to this method or is it pretty much just an always do kind of thing?

If the face was bad then yeah you did the right thing.

It is not a new code at all. Its been around as long as codes have. The problem is that wood gets heated over and over for years causing pyrolysis. This lowers the ignition point of that wood to a point that enough heat can be transfered through the masonry in a chimney fire to ignite the wood. It has happened many many times which is the reason for the code.

 

[bholler]

How can a masonry chimney not touch the house?

Trim can touch on the corners flasking and metal anchors can touch but you need that clearance. It is very clearly spelled out in the code books but no one bothers to follow it.

 

[Ludlow]

Trim can touch on the corners flasking and metal anchors can touch but you need that clearance. It is very clearly spelled out in the code books but no one bothers to follow it.

I see, said the carpenter as he picked up his hammer and saw.

 

[bholler]

I see, said the carpenter as he picked up his hammer and saw.

Even most of the code inspectors miss it or just ignore it. We still see it on new construction all the time. Wall passthroughs are rarely done right either.

 

[Ludlow]

Even most of the code inspectors miss it or just ignore it. We still see it on new construction all the time. Wall passthroughs are rarely done right either.

I worked in new home construction and the bricklayers always bricked tight to the passthrough from what I saw. Maybe the width was enough that it didnt matter I dont know.

 

[blades]

I have a friend that suffered the pyrolsis syndrome about 7 years ago - not a good thing at 2am, 10 g's later all is well- The fire department had to litterally rip everything apart to get at the source.

 

[Mechanized82]

Gotcha. Well, I have to replace a good bit of that wood anyway so I'll be sure to get some clearance in there. Should it be an inch of dead space or will fiberglass insulation be okay between wood and masonry?

Also, after ovalizing the liner to make room for insulation there won't be much space between the terracotta and the liner in the corners. Rather than make a block off plate is it sufficient to just stuff some fiber glass insulation into those corners and call it a day?

 

[Ludlow]

I have a friend that suffered the pyrolsis syndrome about 7 years ago - not a good thing at 2am, 10 g's later all is well- The fire department had to litterally rip everything apart to get at the source.

Was it a built in ZC? My brother ripped out a ZC that was in the house when he bought it to put in a freestanding stove. Found framing that was on top of the ZC that went around the standoffs and was in direct contact with the box. The studs were charred beyond belief. Wish he took pictures it would make your heart skip.

 

[bholler]

I worked in new home construction and the bricklayers always bricked tight to the passthrough from what I saw. Maybe the width was enough that it didnt matter I dont know.

For a crock passing through a combustible wall you need 12" of solid masonry surrounding that crock.

 

[bholler]

Gotcha. Well, I have to replace a good bit of that wood anyway so I'll be sure to get some clearance in there. Should it be an inch of dead space or will fiberglass insulation be okay between wood and masonry?

Also, after ovalizing the liner to make room for insulation there won't be much space between the terracotta and the liner in the corners. Rather than make a block off plate is it sufficient to just stuff some fiber glass insulation into those corners and call it a day?

You if you could get the wood away the whole way up it would then not require insulation. But it will work allot better with it. And no fiberglass is not noncombustible. It could not be used in that air gap and cannot be used in the flue at all.

 

[Mechanized82]

You if you could get the wood away the whole way up it would then not require insulation. But it will work allot better with it. And no fiberglass is not noncombustible. It could not be used in that air gap and cannot be used in the flue at all.

Well that is good to know. Even had a guy who installed these for a living tell me to use fiberglass insulation. That's scary...

Is there anything I could use to fill those empty corners or is the block off plate the best way to go?

I'm looking for a way to avoid the block off plate due to the tight fit up there. The chimney tapers up to that 6x10" flue with a bunch of small steps in the brick which I'm worried drilling for fasteners may just chip off pieces since its would be close to the edge of the brick. If that is the best route though I'll figure something out.

 

[bholler]

Was it a built in ZC? My brother ripped out a ZC that was in the house when he bought it to put in a freestanding stove. Found framing that was on top of the ZC that went around the standoffs and was in direct contact with the box. The studs were charred beyond belief. Wish he took pictures it would make your heart skip.

That is the type of crap we see all the time. I inspected a chimney in new construction for a buyer and all 3 of the class a flues were in contact with framing the whole way up. The hvac guy that did it argued it was zero clearance pipe no need for clearance. Even though we were looking at a sticker on the pipe saying 2".

 

[bholler]

Well that is good to know. Even had a guy who installed these for a living tell me to use fiberglass insulation. That's scary...

Is there anything I could use to fill those empty corners or is the block off plate the best way to go?

I'm looking for a way to avoid the block off plate due to the tight fit up there. The chimney tapers up to that 6x10" flue with a bunch of small steps in the brick which I'm worried drilling for fasteners may just chip off pieces since its would be close to the edge of the brick. If that is the best route though I'll figure something out.

The plate would be just above the opening of the fireplace. Not up at the top. But yes there is rockwool mineral wool and ceramic wool all of which are noncombustible

 

[Ludlow]

Technically yes the fiberglass is combustible. Not like wood but if you hold a torch on it will flame.

 

[Ludlow]

The hvac guy that did it argued it was zero clearance pipe no need for clearance. Even though we were looking at a sticker on the pipe saying 2".

It was in an addition and installed DIY by the previous owner. We know them. They divorced and my brother bought the house off-market.

 

[bholler]

It was in an addition and installed DIY by the previous owner. We know them.

We see that at times as well. Which is why i hate the term zero clearance. There is not much out there that really is zero clearance and it gives people the wrong idea. I have had that argument with multiple contractors before. They simply dont read the instructions. Most homeowners we run into do because they know they dont know what they are doing. But there are still diyers that don't bother with instructions either.

 

[bholler]

Technically yes the fiberglass is combustible. Not like wood but if you hold a torch on it will flame.

Yes the danger is very low but i have seen plenty of melted fiberglass through the years

 

[Mechanized82]

As for redoing the face, I was thinking of using veneer rather than laying brick from bottom to top like what was done originally. Any issues with this or things to watch out for?