Hello all, I have a woodstove in my basement, has 8" pipe going to an 8" round thimble in the concrete basement wall. From there it goes up the chimney,which is lined with 8" round clay flues.I would like to install a stainless steel flexible liner but am torn over whether to insulate or not. As it is, I am guessing that a 7" ss liner will be used, as anything larger will be quite the challenge to stuff down the chimney { such as a 7.5" liner, and obviously 8" is too big }. That said, if I insulate around a 7" liner and then try to stuff down the chimney...well, things might be a little too tight. I have been using the woodstove for years w/o a ss liner and the draft is great and I clean 3 times per season. { I burn wood daily }
To insulate or not insulate
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chimneylinerjames
Feeling the Heat
If you are downsizing you need extra help with the draft. Insulate!! Ask around, people never regret insulating a liner.
Where do I find the room to insulate?? The chimney flue is an 8" round flue. I am using a 7" liner. If I add insulation, will all this fit down the chimney?? Seems like it will be very tight stuffing that down, no??
Maybe a 6 inch liner if your chimney stack is tall enough to give you adequate draft....if it is within your stove's tolerances.
chimneylinerjames
Feeling the Heat
If you use a 7" liner (7.25" O.D.) and 1/4" insulation that will give you 7.75" O.D. That leaves an extra 1/4" of room. I have installed many liners in similar situations. I'm not saying it will be easy but it is possible to do it. You might want to consider using a pulling to help with the install.
A 6" would reduce your draft too much.
A 6" would reduce your draft too much.
Grisu
Minister of Fire
What kind of insert do you have? Why are you thinking now about insulating the chimney? You say you have good draft; are you concerned about the amount of creosote you get out when you do the cleaning?
"What kind of insert do you have? Why are you thinking now about insulating the chimney? You say you have good draft; are you concerned about the amount of creosote you get out when you do the cleaning? "
To answer your question, I am only thinking of insulating now because I have not yet installed the stainless steel liner. I understand that wrapping the ss liner in insulation is required, or is at least recommended. Yes , I do get quite a bit of creosote build up, most being near the thimble connection and approximately 2 feet up from there.
To answer your question, I am only thinking of insulating now because I have not yet installed the stainless steel liner. I understand that wrapping the ss liner in insulation is required, or is at least recommended. Yes , I do get quite a bit of creosote build up, most being near the thimble connection and approximately 2 feet up from there.
Backwoods Savage
Minister of Fire
Welcome to the forum pmgnut.
My concern is why do you have to clean the chimney 3 times per season? It sounds like your wood is not in very good shape for burning. If you can get ahead on your wood piles, it will pay huge dividends to you. For example, we have not cleaned our chimney since the summer of 2009. It simply does not need cleaning! But we also strive to burn wood that has been split and stacked in the outdoor wind for 3 years. No creosote this way and we use a lot less wood to get the heat we need.
Also, you burn wood daily. Does this mean 24/7? Or do you just burn evenings or something similar?
Yes I admit I am not that far ahead on seasoning my wood. It is only seasoned one year. In winter months I burn day and night for about one week straight, then let it go out for a day so I can clean the ashes out. I am wondering if I even need a stainless steel liner, it was just a thought for piece of mind. The chimney is built with 4" x 8" x 16" solid blocks, lined with 8" round clay flues. Approx 20 feet from the thimble connection in the basement to the very top of the chimney.
If your chimney is in good shape then nothing wrong with a clay liner, like backwoods says get dryer wood if yours is not that good and like kingquad states some stoves call for a 6 inch flue which would give you plenty of room if you decide to install a insulated liner.
What wood are you burning, and has it been split and stacked for the whole year, some woods are fine with only a year seasoned.
bag of hammers
Minister of Fire
Since it's easy for me to spend someone else's $ -
- I wonder how many years of service your current stove has provided, and if there may be a newer stove in the plan sometime in the not too distant future? In that case, maybe keep cleaning often, focus on the wood supply as others have suggested, and plan on a 6" insulated liner down the road, when you replace the stove.I'm probably not much help, but I wonder - if you wrestle with a larger liner now, you still have some creosote issues from not-so-great wood, etc., then a couple years from now you get a stove with 6" flue that really drafts and you find yourself wrestliing with the system again, this time trying to figure out how to tone it down (damper, etc.) because of the large flue?
Not even sure if that's of any value to you, or worth worrying about, but just tossing it into the mix fwiw...
Bag of hammers, dont think that will be a problem he has 20 feet of chimney now, I changed out my chimney from a 7 and 1/4 clay liner with 2 90's to a straight up 6 inch insulated chimney, it drafts better but by no means a hoover.
bag of hammers
Minister of Fire
Thanks oldspark for sanity checking that - figured I'd toss in some noise, since one thing i do have experience with is shooting myself in the foot, from not thinking / planning ahead. 
Thanks oldspark for sanity checking that - figured I'd toss in some noise, since one thing i do have experience with is shooting myself in the foot, from not thinking / planning ahead.
Its a valid point, but with only 20 feet of chimney dont think it will be a huge change.
the draft I get from the chimney is more than adequate. When I leave the damper open a bit you can really hear it roar, and opening up the door completely to feed wood, you can really see and hear the draft as well. The stove is in like new condition although it is a 1980's Better-n-ben's unit. Throws tons of heat. My guess is, as many of you have said, is the quality of the wood I'm burning. It is basically just to heat the unfinished basement, { where I tend to spend a lot of time tinkering } although after initial start up, in 24 hours the heat begins permeating through to the first floor which is nice.
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