UN-insulated liners and block-off plates - creosote concerns

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cnice_37

Member
Mar 24, 2011
55
Assonet MA
Hi All,

This fall I made a block-off plate for just above my Jotul Rockland 550 insert. It's tough to be sure it's making a difference, but I can certainly feel the effectiveness on the face of the stone wall comparing just below and just above the install location. The top of the plate is insulated with 1 baffle of Roxul.

I have a 25' flex-liner that is not insulated. I really wish I found Hearth.com before installing this stove!

Common sense would tell me that I have increased the creosote formation given the block-off plate.

How much would it help to insulate the very top of the chimney? I have plenty of leftover Roxul, and once I break through the cement at the top, my guess is it would be easy enough to cram a bunch of Roxul in there, reseal, and hope I've helped any potential problem.

Thanks in advance.
 
Not saying that wouldnt help, but some more info is needed. Interior chimney?, external? Have you considered a pour in type insulation?
 
Coincidentally i have the same stove and setup. This spring is when ill know if creosote has increased or not. I think it will be the same. My top plate is sealed enough to retain heat in my interior chimney.
 
On top of the good advice given already, have you cleaned it yet? Making a decision w/out cleaning it would based on conjecture alone. If you've been burning since fall, now would be a good time for a mid-winter cleaning anyway. This would be especially advisable is this is your first year w/ this stove setup.

If it's not broke, no point in fixing it. Lets see what this chimney has in it!

pen
 
The liner is in a brick chimney, and there is room for a blanket liner.

Like everyone else on this site, I'm looking for the best bang for my buck (or no bucks!) So insulation crammed in there, blown in, blanket, etc. are all considerations.

I have cleaned it but my problem is I'm not comparing apples to apples. I had a gasket fail on me last year around February. With the issues I was having I swept the chimney at that time (in the past it was once a year.)

This year with the odd temps, we aren't burning as much wood. It seems that between sweeps (late Feb - April, late Oct - late Dec), it has been all shoulder season type burning.

Latest sweep resulted in about 2/3 gallon of creosote that fell in the stove. This seemed like the amount I'd get from a full year (Nov - April) of burning, maybe a bit more.
 
If you have an interior chimney and are burning well-seasoned (2 yrs preferable) wood then I wouldn't expect a significant increase in creosote accumulation. If you have an exterior chimney, it would be best to insulate the liner. This can be done with pour-in insulation or, if there's room, pulling the liner, add insulated wrap, then reinstall. Did the chimney at least get completely cleaned and inspected before the liner got installed?
 
To be clearer, that is an external brick chimney.

Chimney was cleaned by myself, liner was installed by the stove shop.... so who knows. House is 25 yrs old, no visible cracks in the brick/mortar.
 
I would think you are building up more creosote because your chimney cavity is cool to cold during your heat cycles causing your liner to cool. Before you put the Roxul in the block off plate, the heat would rise into the chimney cavity and keep it warm, thus keeping the liner warm. Your best to insulate come spring. Check out my install pics of what I did (2nd page). I had it poured in and they didn't have to remove anything as they did it all from the outside.
 
I'am in the same situation. I had my chimney swept before the insert and liner was installed but was told I didn't need a block off plate or a insulated liner. I am now seeing what having a block off plate would do, I really feel I am losing a lot of heat up the chimney and am wondering if I should also have a insulated liner. I looked today to see if I was building a lot of creosote and while there was some build up on the cap, when I looked down liner, there was some but no significant build up from what I could see. Since coming onto this forum I have changed the way I burn and have really learned a lot of good advice.
 
nyyfan said:
I'am in the same situation. I had my chimney swept before the insert and liner was installed but was told I didn't need a block off plate or a insulated liner. I am now seeing what having a block off plate would do, I really feel I am losing a lot of heat up the chimney and am wondering if I should also have a insulated liner. I looked today to see if I was building a lot of creosote and while there was some build up on the cap, when I looked down liner, there was some but no significant build up from what I could see. Since coming onto this forum I have changed the way I burn and have really learned a lot of good advice.
Click to expand...

You are correct by saying you have little creosote buildup. This is because the heat that goes up your chimney is keeping your liner warm during the heat cycling with the stove. If you plan to put in a blockoff plate, make sure you insulate the liner as well because all the heat will stay in your house instead of rising into the chimney cavity. I am assuming you have an external chimney.
 
You are correct by saying you have little creosote buildup. This is because the heat that goes up your chimney is keeping your liner warm during the heat cycling with the stove. If you plan to put in a blockoff plate, make sure you insulate the liner as well because all the heat will stay in your house instead of rising into the chimney cavity. I am assuming you have an external chimney.
Click to expand...

Yes it is an external chimney. I think I am going to have some projects this summer. Where do most people purchase items like the insulation blanket for the liner or the materials to make a block off plate?
 
I'm replying to this because I'm considering the same thing. Aren't we all.

Is this about right? - unhook the liner top and bottom, pull it all the way out, wrap it in insulation, put it back, then blockoff etc.

Is there a blanket kit?

If you wanted to insulate the TOP plate where would the insulation go? If under the plate then how does it keep from dropping?

Thanks
 
Brookwood said:
I'm replying to this because I'm considering the same thing. Aren't we all.

Is this about right? - unhook the liner top and bottom, pull it all the way out, wrap it in insulation, put it back, then blockoff etc.

Is there a blanket kit?

If you wanted to insulate the TOP plate where would the insulation go? If under the plate then how does it keep from dropping?

Thanks
Click to expand...

Brockwood, I checked with a local store and they do have an insulation kit for the liner. It looks like for my setup I will have to take the cap off, disconect the bottom and top and pull the liner out. Wrap the liner and then I guess they also have a mesh that goes over the insulation so that when you put it back in it won't rip the insulation. I asked about a block off plate and they were questioning why I would want to do that. I gave em my reasoning and said that I could get some other pieces of that insualtion to put up by the damper and that should do the trick. I might also fashion two pieces of steel to hold the insualtion in place and then some high temp silicone to reseal the cap. They said the insulation for a 25ft liner should run about 300 and an extra 20 or so for the block off plate, but you might be able to just order it online for less. Hope that helps.
 
nyyfan said:
Brookwood said:
I'm replying to this because I'm considering the same thing. Aren't we all.

Is this about right? - unhook the liner top and bottom, pull it all the way out, wrap it in insulation, put it back, then blockoff etc.

Is there a blanket kit?

If you wanted to insulate the TOP plate where would the insulation go? If under the plate then how does it keep from dropping?

Thanks
Click to expand...

Brockwood, I checked with a local store and they do have an insulation kit for the liner. It looks like for my setup I will have to take the cap off, disconect the bottom and top and pull the liner out. Wrap the liner and then I guess they also have a mesh that goes over the insulation so that when you put it back in it won't rip the insulation. I asked about a block off plate and they were questioning why I would want to do that. I gave em my reasoning and said that I could get some other pieces of that insualtion to put up by the damper and that should do the trick. I might also fashion two pieces of steel to hold the insualtion in place and then some high temp silicone to reseal the cap. They said the insulation for a 25ft liner should run about 300 and an extra 20 or so for the block off plate, but you might be able to just order it online for less. Hope that helps.
Click to expand...

Wouldnt it be easier to put insulation and a block off plate then pour insulation down from the top? Probably cheaper too.
 
I have the same stove and setup. I do have a block-off plate. I do not get any creosote build up but do get soot (powdery) build up over time. I keep debating getting the insulation as well. I think it would make it better, but not sure by how much. Seasoned wood is still your best friend.
 
Mine is an external 20' chimney and I seem to get too much creo. Much of that is user error. I do see that pouring insulation in would be good except if you ever have to remove the liner for whatever reason. I don't know if I can bring myself to buy a wrap for $300. The mesh sleeve sounds cool.

There is a ton of stuff here but this is the first time I've read that some liners would have regs on how thick the insulation should be. I will have to see if my original install statement says who the liner manufacturer is and check the specs.

Thanks for the comments.
 
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