Insulation for stainless flue liner

[stihl025]

Is is absolutely necessary to insulate a stainless flue liner? I have seen some mention of it on here, but not much. I am refurbishing an old wood furnace to install in the basement of my house. The house has two clay lined flues side by side (from way back when of the coal furnace days) that run up the center of the house. I was thinking of purchasing a complete liner kit (from ebay). Do I really need the insulation?

 

[Ductape]

As a guy who just had a fire, partially due to an uninsulated liner, i say INSULATE ! Yes, it can be done without...... but i advise you to insulate. As in the previous post, better draft, less chance of creosote deposits (my problem), and an added safety barrier.

In my case, my installer said it didn't need to be insulated as my chimney was not on an outside wall. What happened in my case was...... it allowed the liner to rest against the inside of the chimney creating a "hot spot". Its cheap insurance.

 

[Wood Scrounge]

I have run it both ways with and without Insulation and without question the Insulation is safer and WAY more efficient. You will notice a difference right away in your room temp as well as the cleanliness of the pipe.
SHop around you can usually find goode deals on the internet.

 

[bearsfeat]

tag along...

Well,
I am considering the same thing for my planned install. I take the advice in this thread to heart and will not consider installing a liner without insulation.

But, I have a question. How do I go about purchasing what I need? Sounds like a basic "geen ear" question - and it ought to. I am a bit green in this realm.

Please comment on these questions I have:
step 1 is to measure the flue WxDxL, right?
(is 8"x10" a common size for a clay rectangular flue?)
(What is L actually? from the cap to the stove would be my guess. Should I add a foot just in case?)
(Most stoves want a 6" pipe, if I have an 8" width in my flue, is 1" per side enough insulation? Is that a standard?

Thanks for your time and patience. I will hopefully learn all that I need to before next winter. I already have my woodpile started

-bearsfeat

 

[Kuuma200]

Is is absolutely necessary to insulate a stainless flue liner? I have seen some mention of it on here, but not much. Do I really need the insulation?

When my chimney man installed a rigid SS liner in my brick chimney he insulated in the following way. He stuffed rags around the liner above the T at the bottom. He then dropped down moist mortar to the rags and let it dry. He then dropped down Vermiculite to the dry mortar ring and filled it up to the top. He then covered it with mortar at the top.
From my experience, the place where creosote coats and clings the most; is above the roof line. So this would be the most important place for insulation around the liner.

 

[Ductape]

Well,
I am considering the same thing for my planned install. I take the advice in this thread to heart and will not consider installing a liner without insulation.

But, I have a question. How do I go about purchasing what I need? Sounds like a basic "geen ear" question - and it ought to. I am a bit green in this realm.

Please comment on these questions I have:
step 1 is to measure the flue WxDxL, right?
(is 8"x10" a common size for a clay rectangular flue?)
(What is L actually? from the cap to the stove would be my guess. Should I add a foot just in case?)
(Most stoves want a 6" pipe, if I have an 8" width in my flue, is 1" per side enough insulation? Is that a standard?

Thanks for your time and patience. I will hopefully learn all that I need to before next winter. I already have my woodpile started

-bearsfeat

Yes, first step is taking measurements.

I'm unsure what is "common" for flue tile dimensions. My flue is 8x12
"L" will be from the rain cap to your thimble. A liner does not go all the way to your stove..... your stovepipe goes into your liner. Most commonly, the liners come as "kits" in commonly used lengths. If you need 18 feet, you may have to purchase a 25 foot liner kit. The parts are available seperately, and you defintely can find vendors to sell you the exact footage you need. I suspect you will find it more affordable to buy a complete kit though.

One inch of insultion should be plenty (according to my chimney guy). You can also wrap your liner in insulation (the stuff made for liners), then it is surrounded wth a chicken wire type wrap to hold the insulation to the liner. This makes a less permanent installation, should you think you may want to remove the liner for some reason in the future. I suggest the poured in insulation though..... since we all know stainless steel is guaranteed never to shrink, stink, wrinkle, or rust.

My installer says the same thing Kuuma200's said. Insulating above the roofline is crucial.

I have been given prices around $1600 - $2000 to clean, line, and insulate my chimney which is approximately 16 feet (single story). I suspect that if i shopped around, i could do it myself under a thousand. Keep in mind.... there s more than one guage of liner. I'd say a thicker liner is always going to be better than a thinner liner. The guage of the stainless will affect price, so compare apples to apples here.

 

[johnha]

As a guy who just had a fire, partially due to an uninsulated liner, i say INSULATE !

If it was 'partially' due to an uninsulated liner, what was the balance of the problem?

I'm not trying to be a smarta$$ here, but I had my chimney cleaned then relined it last March to install my insert. The 6" liner was a snug fit in the terra-cotta so there was no way to wrap it. After intstalling it I insulated it top and bottom and sealed the old chimney to the liner at the top and bottom with stainless steel panels.

I'm trying to determine if I should attempt to insulate but I don't see how I would. I clean my chimneys (two woodburners) at least twice a year.

 

[Ductape]

If it was 'partially' due to an uninsulated liner, what was the balance of the problem?

I'm not trying to be a smarta$$ here, but I had my chimney cleaned then relined it last March to install my insert. The 6" liner was a snug fit in the terra-cotta so there was no way to wrap it. After intstalling it I insulated it top and bottom and sealed the old chimney to the liner at the top and bottom with stainless steel panels.

I'm trying to determine if I should attempt to insulate but I don't see how I would. I clean my chimneys (two woodburners) at least twice a year.

"Partially" because our house is a hundred and thirty years old, and was built long before terra-cotta flue tile. My chimney is brick only, with no flue tile of any kind. Having flue tile is a substantial layer of insurance compared to what i have. With my chimney being in a wall (as opposed to exposed), we could not see the less-than-perfect condition of the mortar and brick.

So add

1) Hundred and thirty year old chimney with some (no matter how often it was swept) creosote deposits in the cracks

2) No terra-cotta (nor any other) flue tile

3) Uninsulated liner which was able to rest against the inside of the chimney

Equals = fire

All in all, we were very lucky. Fire was very small.

I've learned a lesson the hard way..... could've been harder. I feel that it would benefit you to pour insulation around your liner. Do you HAVE to? No, but it could only be a benefit. You are already way ahead of where i was with my chimney.

 

[Ductape]

P.S. I swept my liner several times a year also

 

[ozarkjeep]

I think its less important to insulate your liner because it is centrally located within the house.

exterior chimneys get more of a benefit from being insulated.

If you have good burning habits, a good stove, and know how to operate it, you wont have any creosote/fire problems from NOT having an insulated liner.

 

[woodfarmer]

check into your local regulations, some areas require an inch of air space around the ss liner

 

[toolhawk]

ss liner insul. !!!

I am going to insulate mine this summer , as I know I have a tall completly outside chimney , but my chimney is completly new 6" ss liner,12" crock , double bricked on the outside , so if my stove runs continously and the top of chimney is sealed ,bottom is sealed you would think that space around the liner inside the crock would be heated ?? I just cleaned my chimney and ONLY the top 36 inches had any build up ,so I know its cooling down at the top. So I just read that some codes call for 1' OF OPEN SPACE AROUND LINER !! so this vermiculite stuff is rated to be right against the liner at extreme temp ?
Thanks
I WILL POST A PIC OF MY CHIMNEY HERE WWW.FOTKI.COM/TOOLHAWK