Chimney Liner Allowed

Reply

  #1  
Old 02-02-08, 08:33 PM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
Chimney Liner Allowed

Greetings,

Our house was built in the 1920s and has a large chimney with 2 clay-tile lined flues that are in good shape (tiles not cracked and chimney is solid). I have a wood stove that I would like to connect to one of the flues. The stove requires a 6" pipe but the flue is 12"x7" (so much larger) and there is about a 35' total rise (the whole chimney sticks up several feet past the peak of our roof). I am getting mixed responses from people. One professional I spoke with said that I absolutely MUST install a stainless steel liner and would have to even if the flue was the correct size. Others say I don't need to. What I'm wondering is why it HAS to be stainless steel? What would be wrong with simply using 6" stove pipe all the way up the flue? Since the flue itself is already protected from any combustible materials, why would it be WRONG/IMPOSSIBLE to simply use a regular single wall stove pipe or something other than stainless? I realize stainless is much better, but am on somewhat of a budget here and that's a lot of chimney.

-Aaron
 
Sponsored Links
  #2  
Old 02-03-08, 02:59 AM
Banned. Rule And/Or Policy Violation
Join Date: Nov 2007
Posts: 259
Received 0 Votes on 0 Posts
we had a parallel situation,,,

but w/50's home,,, it all start'd w/fireplace in basement,,, stoned up the opening & left a thimble into which we place the stove's flue,,, work's well for 3yrs,,, then noticed the clay liner was shot along w/the top 3' of the chimney,,, relaid that stone w/new flue & dropp'd in 12" id triple wall's s/s steel piping,,, that was 30 yrs ago & its still working fine.

anything other'n s/s'll rust & be attack'd by wood acids releas'd by burning,,, everyone's on a ' budget ' but better its done correctly than have your ins co walk when there's a problem later on,,, imo.
 
  #3  
Old 02-05-08, 01:50 PM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
So what liner to go with..

Thanks for sharing your experience. I think I'm being convinced to move the direction of a stainless steel liner despite the cost. A previous owner of our house decided to vent both the hot water heater (natural draft) and furnace (fan assist) directly into the clay-tile lined 7x12 flue. We have had trouble with water damage on walls and ceilings surrounding our chimney ever since owning this house and a couple of years ago I had rebuild almost half of the chimney sticking out the top of the roof. The more research I'm doing on-line, the more convinced I'm becoming that this is because these appliances are vented into the chimney without a liner -- probably some of the flue gases are condensing in the chimney before reaching the roof. So, now we are wanting to hook a wood stove into the same flue space and here's what I'm finally considering (if I can afford it):

1. Run a 6" stainless steel liner down the flue to connect the wood stove.
2. Run another 5" aluminum liner down the same flue (there is plenty of room for both) to connect the hot water heater and furnace (I checked sizing charts and with a 20' chimney looks like I can't get away with a 4" pipe going up so will need a 5").
3. Pour some kind of chimney insulation down to fill in the gaps between the two pipes and the clay tile liner.

My only remaining question is whether or not I can put both a stainless and aluminum pipe in the same flue. I don't see why not and this at least get the project somewhat closer to the affordable range ($100 for alum. liner kit vs. $300 - $400 for the stainless plus another $400 or so for the 6" stainless liner kit.)

Any recommendations or concerns? Thanks for the help.
 
  #4  
Old 02-05-08, 02:01 PM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,389
Received 0 Votes on 0 Posts
Wink

Id use just what you have there. Put in what is called a check draft and damper in the smoke pipe to the flue If you want. But if the smoke pipe and the stove are tight you can control it with the front draft on the stove so you dont have to much draft is all. If the liner is good and you dont have anyother vent at all into this flue Id go for it.
 
  #5  
Old 02-05-08, 07:43 PM
Member
Join Date: Jan 2008
Location: East Coast
Posts: 19
Received 0 Votes on 0 Posts
Cool

Get a pro in there or don't do it at all.

The woodstove must have a listed liner. That means specific insulation to meet UL1777 for a 2,100F chimney. No, you cannot share the flue with another liner, esp. a cheap piece of aluminum junk.

have a pro reline the heater flue with 316Ti stainless steel properly sized. Not a DIY project.

Have his also bid on the woodstove installation. he will need to check the clearances as well.

Regardless, you need a level II inspection first and foremost.

Hth,
Hearthman
 
  #6  
Old 02-05-08, 08:06 PM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
"No, you cannot share the flue with another liner, esp. a cheap piece of aluminum junk."

Why can't two liners be put in the same flue? Are you saying this is not possible at all, or just not if one is an alluminum? The pros in our area just recently installed 2 liners for different gas stoves in the same flue of our in-laws house. Was that wrong or is it because this is a WOOD stove that 2 are not allowed? Is there something in UL-1777 stating that a wood stove cannot be vented to a liner in a flue that also houses another liner?

"That means specific insulation to meet UL1777 for a 2,100F chimney."

The insulation I'm looking at is here: Insulation Mix
Given the vendor, I'm assuming this will meet the UL-1777 standard, but I can check into that before purchasing.

"have a pro reline the heater flue with 316Ti stainless steel properly sized"

This is actually what I am planning for the wood stove. It has a 6" vent outlet and I am planning to install a 6" 316Ti stainless liner kit - 25' length.

"he will need to check the clearances as well."

Why is it necessary to have a Pro check clearances when they are all clearly specified on the wood stove's documentation? Also, given that a permit is required to do this work, a city inspector will come and check things out anyway before I operate the stove. I have done all the re-modeling in our house myself so far. I think I can figure out how to run a tape measure.

I thank you for your concerns. I realize one must be especially careful in these types of installations, which is why I'm asking questions. But in my mind this is still a do-it-yourself job.
 
  #7  
Old 02-07-08, 08:18 AM
Mark_MS's Avatar
Member
Join Date: Oct 2006
Location: usa
Posts: 117
Received 0 Votes on 0 Posts
You need to check with your local building inspector regarding codes about what you are proposing.
Most local codes will not permit two flues in a "given" area, unless each flue is chambered from each other ie each being enclosed with flue on the inside.
You also need to inform your insurance company that you are doing this work, either professionally or DIY. If you don't and your house burns down due to a DIY stove install guess what you will not be able to recoup your loss.
Spend more $$$'s now and have it done right and to code. It will be money well spent.


Mark_ms
 
  #8  
Old 02-07-08, 09:03 AM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
Will check with codes...

Thanks for the advice, Mark_MS. I'll try to get down to our codes office today or tomorrow, though I'm not sure what they're going to say. We had called them initially (before I posted here) and our city codes guy seemed to suggest that we could just run black stove pipe up the chimney (which everyone else I've talked to says absolutely NOT to do).

I want to do this right and will certainly notify our insurance company, but part of the challenge is that even professionals I talk to seem not to agree. (Some have told me I can put two liners up the chimney and others say I can't). I even talked to one guy who thought I could just put a liner in the chimney and let the hot water heater & furnace just vent in the space around it. So even if I were not doing this myself, it seems that I still need to research the right way to do it so I can tell whether or not the pro knows what he is doing.

At this point, assuming the codes in our area allow two liners in the same flue, I think my only remaining question would be whether I can use stainless for the wood stove and aluminum for the appliances (they are not high efficiency) or if I must have 2 stainless steel liners.
 
  #9  
Old 02-07-08, 12:43 PM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
Think I'm Good to Go

Well, I just spoke with the person in charge of codes in our city and he was very helpful. He said that YES you can have 2 liners in the same flue as long as they will fit and both go all the way to the top of the chimney. I found a pretty good deal on 2 stainless steel flexible liners. Still more than I was initially hoping to spend, but the vendor said that I should NOT put an aluminum liner in the same flue where the wood stove vent liner would be (he said the temperatures would melt the aluminum).

So I guess my final plan (if I can still afford to do all this!) is two 316Ti stainless steel liners (Flex King brand) - one 6" for the wood stove and one 5" to vent both the furnace and hot water heater. I'll then get the mixable UL-listed insulation (linked earlier) to pour in and fill between the liners and the 12x7 flue.

I think that's everything unless somebody here sees a problem with this plan. (?) If/When I end up doing this I'll try to report back here on how things went.
 
  #10  
Old 02-08-08, 07:11 AM
Member
Join Date: Dec 2007
Location: USA
Posts: 84
Received 0 Votes on 0 Posts
Why use insulation mix compared to the insulation wrap?.. No mixing needed.

Do you get the chimney inspected for the work your trying to perform?


Originally Posted by schroedogg View Post
Well, I just spoke with the person in charge of codes in our city and he was very helpful. He said that YES you can have 2 liners in the same flue as long as they will fit and both go all the way to the top of the chimney. I found a pretty good deal on 2 stainless steel flexible liners. Still more than I was initially hoping to spend, but the vendor said that I should NOT put an aluminum liner in the same flue where the wood stove vent liner would be (he said the temperatures would melt the aluminum).

So I guess my final plan (if I can still afford to do all this!) is two 316Ti stainless steel liners (Flex King brand) - one 6" for the wood stove and one 5" to vent both the furnace and hot water heater. I'll then get the mixable UL-listed insulation (linked earlier) to pour in and fill between the liners and the 12x7 flue.

I think that's everything unless somebody here sees a problem with this plan. (?) If/When I end up doing this I'll try to report back here on how things went.
 
  #11  
Old 02-08-08, 07:49 AM
Member
Thread Starter
Join Date: Jan 2008
Posts: 12
Received 0 Votes on 0 Posts
Why use insulation mix compared to the insulation wrap?.. No mixing needed.

Well, the flue width is more like 6.5" and there is actually a spot near where a hole was previously drilled into the clay tile liner (actually where I'm connecting the wood stove) that might be even a little narrower. So one reason is just not sure if it the wrap will fit with a 6" liner. Plus having a 6" and 5" where I only have 12" of length would mean it probably won't fit the other direction either. The other reason is that pouring a mix in will insulate both pipes at the same time plus fill in any gaps. It's a UL-1777 insulation mix. The vender said it wasn't quite as good as the wrap but would probably be the best option for my installation.

Do you get the chimney inspected for the work your trying to perform?

Our city codes inspector will come and inspect everything after the work is done.
 
  #12  
Old 02-08-08, 03:48 PM
Member
Join Date: Jan 2008
Location: East Coast
Posts: 19
Received 0 Votes on 0 Posts
Exclamation

Each flue must be separated by a nominal 4" wythe wall so one liner per flue.

The liners are not listed for use twinned, so the liner listings would be voided by twinning.

If you have zero clearance btw the chimney exterior and combustibles, you will need the maximum insulation. That is dictated by the liner listing but almost always that will require 1" of Thermix or two wraps of foil backed ceramic fiber blanket.

I went on the website for this liner and it is NOT listed. "Tested and approved to UL-1777 Zero Clearance". This is not the same as having been tested by a recognized testing lab and having passed. You can test all you want but did it pass? There is no such thing as "approved" to UL standards. Who approved it--the mfr.??? Think about why this liner is so cheap. Because they did not pay to test it nor do they pay the maintenance fees for the testing agency, such as UL, OMNI, ETL, Warnock Hersey, etc.) to enter the factory at least 4 times per yr. to inspect the process, test samples, verify mill certificates on the steel, etc. Professional liners are listed by one of the above labs and warrantied for lifetime or even transferrable lifetime. So, what are you going to do when the liner comes apart or arrives damaged? Who you going to turn to, some internet company?? Good luck.

I recommend a pro check the clearances because very, very few homeowners get it right.

If you have 6.5" flue ID the maximum liner dimension OD would be 4.5" to allow for 1" of Thermix. If ceramic blanket, you might be able to get it down with a 5.0" OD but it will be tight. If it pinches the blanket, you have a hot spot and it voids the warranty and listing and thus violates the codes.

No offense but very few building inspectors know what they are looking at with chimneys and fireplaces. Remember, this is the same character who told you you could reline a chimney with black unlisted stove pipe. Unbelievable...

Did you run this by your insurance company first? If you sneak this in without telling them, they may have the right to drop your insurance.

If you twin the liners and have a chimney fire, yes, you could melt or damage the aluminum liner. Aluminum melts around 1,250F--chimney fires burn around 2,000F.

Hearthman
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description: