Chimney liner insulation?

[Hogwildz]

I am hopefully soon going to be riding my masonry fireplace insert which is Feugo Flame and pc of junk as far as I am concerned, with a new insert. Looking at Regency i3100, Pacific Energy Summit, or possibly Avolon Olympic. I need something big to try and heat my 2900 sq foot home. Fairly wide open floor plan. Anyone have one of these models? And your experiences with it? I was at a dealer looking at the Avalon and inquired about the S.S. liner and insulation. Oh BTW the existing chikney is 11"x11" inside or 13"x13" outside teracota liner surrounded by block. Of course I will be using a 6" S.S. liner. My two qustions are:

1. One guy told me the flexible liner is better than rigid. That it expands and contracts therfore loosening buildup of creosote. Sounds like a bunch of bull to me. I would think all the ridges would coolect creosote easier? Any input qould be greatly appreciated.


2.The dealer said the only insulation I would need is at the bootm around the old damper & at the top around the liner and under the top plate. I was looking more at a full wrap of insulation top to bottom with the stretch mesh reatining netting around it? Any thoughts? Thanks.

 

[webbie]

On the liner, rigid is much thicker than flex and smooth wall drafts better - you often have to use some flex at the bottom to properly get through the damper.

A metal block off plate should be custom fit at the bottom - instructions on this site at the info link below.

No doubt the ultimate job is insulated and sheathed.....although it certainly is not meant as an excuse, most liners are NOT insulated because of multiple reasons - usually fit and cost. They tend to work fine either way, but if you are in especialy cold climate the insulation will bring a lot of added benefit - easier startup and better operation.

 

[Hogwildz]

Thanks for the advise, much appreciated. I am in PA mountains, it gets cold but not like New England or Canada. Do you think I could forgo the liner insulation?

 

[Mike Wilson]

I have a 6" flex liner in a 12" clay flue, and I skipped the insulation. I did, however, fabricate a block off plate at the damper and cap the flue. My theory is that that 6" liner within the clay tile, with the top and bottom closed off by the plates, will hold some heat, and thus help draft. Would a rigid, insulated flue be better... no doubt. But in my mind the net net analysis favors skipping the insulation if you are in an enclosed clay flue. (yeah, I know its a huge heat sink... but its better than being in the open air).

-- Mike

 

[elkimmeg]

1. One guy told me the flexible liner is better than rigid. That it expands and contracts therfore loosening buildup of creosote. Sounds like a bunch of bull to me. I would think all the ridges would coolect creosote easier? Any input qould be greatly appreciated.

2.The dealer said the only insulation I would need is at the bootm around the old damper & at the top around the liner and under the top plate. I was looking more at a full wrap of insulation top to bottom with the stretch mesh reatining netting around it? Any thoughts? Thanks.

"the one guy coments"
this guy just graduated from being a Cumberlands farms clerk. You are correct total BS Let me set the record straight. First I'm not selling you a thing. A smooth liner is superior liner. The smooth surface has a lot less friction to impeed draft, less chance t for collection of cresote, and easier to clean, But much more expensive. A flexible liner is one piece less expensive and code compliant in order to obtain the UL listing lnslation is required.

If your location is an exterior chimney all the more reason for insulation
the best and correct installation would include a damper block off plate Batt insulation is not an approved application to seal the damper, It has to be ridgid corrrosian resistant material usually alumium or galvanized steel. Again to obtain code compliance it must be UL listed, translation it is required to be insulated.
The top flue exit shall have a weather proof cover and a proper termination cap installed on the liner.

All the advice you received was incorrect I would be leary purchasing a stove and installation contract from these un informed salesmen. It is quite evident that none have read the manufacture's manual or have a clue as to code compliance.

Stick around here and ask away. You already are more educated that the sales reps you spoke to. Glad to help you. The most important part of wood burning is getting optimal draft. More important than the brand stove you end up with.

 

[webbie]

Well, Elk, he might not have much choice about who to buy from! Only "x" amount of dealers in any given area.

While not making an excuse for BS, it turns out that EITHER a decent flex or a rigid liner would be vastly better than no liner and are both fine for doing the job. So the salesperson was just doing what typical salespeople do - making the case for their product. In other words, I would be satisfied with a flex liner in my own home (a decent one) and I suspect most other people also would be - but you specifically asked about which is better, and rigid is the correct answer there.

Insulation is a tough question. If chimney is in poor condition and was not built properly (most are not), then the insulation is required to bring it back up to code. We have been through this many times here before, and it's a bit of a never-ending story. Let's say it this way - if your chimney is safely usuable as existing, then the insulation is not needed for the UL listing. It would only be needed for better draft, startup, etc. If the chimney is not usable (unsafe) for wood burning as-is, then insulation is required by the liner manufacturers to bring the chimney up to modern specs.

It's one of those round and round questions.

Having been in the business for 27 years - all through those years when almost no one installed ANY liner - I tend to look at this from the bottom-up, meaning that every improvement is an important step in safety and operation. At the same time, we live in the real world where there are often constraints...for instance, in many jobs it is next to impossible to fit insulation in. I'm pleased that they told you to line it in the first place! Many shops would not.

Sorry for the confusion.....but it is confusing even to us!

 

[Rhone]

What the insulation does on other issues is let you have a fire when it's warmer outside than without the insulation, and particularly useful for short or exterior chimneys. Interior chimneys, insulated liners, and tall chimneys enable you to burn a fire when the temp outside is higher. Someone with a 14 foot chimney and insulated liner may have fires when it's 50F or less but choosing an uninsulated liner that may mean 45F or less instead and very annoying.

It is really annoying because I couldn't get fires going unless it was 45F or less (ranch, exterior chimney, uninsulated). Coming home to a 64F house and seeing it's 48F outside I could either turn on the boiler or wait. I waited, and waited, went to bed setting my alarm for 2AM to check if the temps wre 45F or less so I could light a fire... no one should go through that. I just finished ripping out my liner and redoing the install to maximize every ounce of draft and purchased an extend-a-flue. I've lit a fire at 52F outside and it went like a race horse! That is so nice. You don't want to be the guy in PA who can't light a fire unless it's 45F or less(everyone's situation is unique). If you have a ranch and chimney on the exterior don't risk it and get the insulation. If you have a 2 story w/interior chimney in good shape you'll probably be fine without.

I love rigid liner, it's easy to clean but you will probably have to have some flex. Most inserts with rigid liners have the bottom 5' or so flex to allow movement of the insert once installed, to navigate through the damper area, and to handle any chimney offsets and then rigid all the way. I find flex tears easy particularly once started, I'm sure each brand is different and the flex I got from my local dealer is not good quality. I can't say enough about how great the quality of Heat-Fab rigid is.

 

[zzr7ky]

Hi -

I'm in the Great Lakes area. I went with 17' of Rigid 6" liner with Insulation. I have the same flue tile size. I lowered the rigid down on a hook screwwed to the end of a couple lengths of steel electrical conduit I use to clean the chimney. I'm thrilled with the precise control I get with the draft and it doesn't care if I'm running the drier, or exhaust fan in the kitchen.

Even in mild weather it draws so well a bic butane flame is drawn up and out in front of this setup. I really like it. I mail ordered.

Get at it before the weather closes in!

ATB,
Mike P

 

[Hogwildz]

Hi -

I'm in the Great Lakes area. I went with 17' of Rigid 6" liner with Insulation. I have the same flue tile size. I lowered the rigid down on a hook screwwed to the end of a couple lengths of steel electrical conduit I use to clean the chimney. I'm thrilled with the precise control I get with the draft and it doesn't care if I'm running the drier, or exhaust fan in the kitchen.

Even in mild weather it draws so well a bic butane flame is drawn up and out in front of this setup. I really like it. I mail ordered.

Get at it before the weather closes in!

ATB,
Mike P

oK, even more questions,........
Did you use single wall or double wall. I am leaning towards double wall due to it being insulated between layers. Eliminating the need for insulation wrap.
Did you use flex liner at the bottom to angle around old damper & into top of insert?
After comparing cost of the flex & rigid, rigid really is not a lot more than the flex.
So far I am looking at Simpson Dura-liner rigid with a Dura flex bottom, Rhino rigid, although it is single wall, hence insulation wrap. There were a few others. And a few others as mentioned above by others. I am really leaning to the dura liner system which is almost in line with what the dealer wanted to charge me for 304 s.s. flex liner.
Heres a diagram of what I'd like to do.

 

[zzr7ky]

Hi -

I went with RHL Rigid and the Simpson snap over insulation (,$200 for a case of 8 2' sections delivered. I also considered the Simpson double wall. Inspectors here said it was not a listed usage. Might gather condesation or something.

I can tell you it draws like mad. It was 55 degrees and very damp so far this week and the stove jumps to life. I think the insulation was worth it. Don't be afraid of rigid iff you have clearance.

ATB,
Mike P

 

[Hogwildz]

With 11" x 11" ID exisitng chimney, I think the rigid would fit fairly easy. Chimney it nice and straight, built in the 60's I think, and the block is plumb and true after all these years.
If the double wall is insulated and kept tight up top, wheres would condensation come from? Plus the stuff I am looking at is S.S. inside & out. I dunno, still weighing availablility, product & price.
Still leaning towards insulated double wall down to a flex through shelf to stove. Price difference may not be all that much more than just rigid with insulation wrap etc.
Thanks for the input though, much appreciated.

 

[zzr7ky]

Hi -

Read the usage that the UL listing was granted for. The double wall isn't sealed. there are small holes at the ends so pressure can equalize. I was prepared to do the same thin you are suggesting. Local inspector and folks here convinced me to go with Rigid and insulation.

I went into 11"x11" also. Verify that the clearance is there. I screwwed a bucket top of the right size to a pole and lowered it down to ensure all was well. I have 2 flues. Only 1 had clearance. The rigid and Simpson Saf-T-Wrap installed easily. It drafts very well, great control even in weather in the 50's or better.

ATB,
Mike P

 

[Hogwildz]

Hmmmm, I didn't realize the small holes. I was just trying to avoid the external insulation and pre insulated would have been easier. I still want to go rigid, but am considering the flex. The Dura Flex site does show it as used in an insert liner application though. Maybe this one can be used. I will research more. Here is a link if your interested........http://www.duravent.com/catalogs/dliner/L405about.htm
Mind if I ask which brand rigid you used and did you purchase online? Was the Saf T wrap difficult to install &/or get to stay put on pipe? I apologize for so many questions. I have been researching this to death. I am the type that has to gather as much info as possible , I reasearch stuff to the point of obsession LOL. I just hate to commit to something, get it done, only to find a better product or way for the same money and regret it.
So you ran rigid up to top, but with flex from just over smoke shelf to insert? Did you insulate the flex also? Did you use a coupler from flex to rigid?
Oh you ran through a ZC? I have an old masonry, but sides top & back are plate steel. From 1960's.
I like the bucket idea, thanks for the advice, I will try that myself. Only other question I have right now is, the top plate for liner kit is advertised as 13" x 13". is that the exact size, or will it wrap over the sides of the clay flue when installed? Thansk for you input. And have a great weekend!