What Will Draft Better

[Berner]

Going nuts lately with research, calling, asking questions etc about liners. Trying to learn everything I can before pulling the trigger on a new liner.

As I see it I have a few options for a liner. I would like you guys to rank each setup in order of what you think will draft the best.

It's a 17 ft run up an exterior stone chimney. The terracotta tile is 7.25"X11".

Option 1) Rigid pipe with 1/4" insulation blanket.

Option 2) Rigid pipe with pour in insulation. I'm skeptical of the pour in because I don't want to have a liner that I can't replace. The loose pour in is the option here.

Option 3) Heavy Duty flexible with 1/4" insulation.

Option 4). Heavy Duty flexible with pour in insulation.

Option 5) Ovalized Heavy Duty flexible with 1/2" insulation. With an ovalized pipe I gain the room to put the 1/2" insulation blanket around.

Option 6). Ovalized Heavy Duty flex with pour in insulation.

Thanks in advance for your opinions!

 

[begreen]

Ovalized with the 1/2" insulation? Is removing the tile liner an option so that you can go 6" round with 1/2" insulated liner?

 

[bholler]

Ok well 1/4" insulation will not get you up to code. And you wont fit a 6" liner in there with 1/4" wrap either. You need to either remove the clay or ovalize the liner. You absolutely can replace a liner after using pour in insulation but if you are doing it yourself i would not recommend that type. I would go with ovalized heavy flex with 1/2" wrap. But check with the stove manufacturer to see if it is ok to reduce the volume by ovalizing a 6" we use 7" usually when we ovalize.

 

[Berner]

Ovalized with the 1/2" insulation? Is removing the tile liner an option so that you can go 6" round with 1/2" insulated liner?

How would you remove a terracotta tile liner?

 

[bholler]

Bg beat me to it

 

[bholler]

How would you remove a terracotta tile liner?

With a tile breaker and rods not a diy job

 

[Berner]

Ok well 1/4" insulation will not get you up to code. And you wont fit a 6" liner in there with 1/4" wrap either. You need to either remove the clay or ovalize the liner. You absolutely can replace a liner after using pour in insulation but if you are doing it yourself i would not recommend that type. I would go with ovalized heavy flex with 1/2" wrap. But check with the stove manufacturer to see if it is ok to reduce the volume by ovalizing a 6" we use 7" usually when we ovalize.

Yes spoke with Woodstock and if ovalizing a larger pipe it is necessary to use a 7" to keep the same area of a 6" round.

Why would you not recommend doing the pour in insulation? From what I understand there are two types of pour in. A dry substance that you pack in from the top that collects on top of your bottom block off plate. Yes if I needed to replace a liner it would be messy but doable. The other kind of pour in you mix with water and I thought it set up like concrete making it impossible to replace a liner with. Do I not have this correct?

Heavy Duty ovalized with 1/2" wrap sounds sweet but super expensive. If that's what needs to happen I will do it but want to explore and understand all my options.

 

[begreen]

Though one patient soul here recently did remove his own tiles.

 

[Squisher]

Can that only been done if it's a straight run, or is it possible to bust out chimneys with offsets?

 

[bholler]

Why would you not recommend doing the pour in insulation? From what I understand there are two types of pour in. A dry substance that you pack in from the top that collects on top of your bottom block off plate. Yes if I needed to replace a liner it would be messy but doable. The other kind of pour in you mix with water and I thought it set up like concrete making it impossible to replace a liner with. Do I not have this correct?

Well no you don't. Loose fill is no longer an accepted liner insulation it settles and with the expansion and contraction of the liner it packs in really tight and hard at the bottom. So you would use the mix and yes you can still pull the liner i have pulled quite a few. It does not set up very hard it needs to let that liner move. But it takes allot of experience to get even distribution around the liner and keep that liner centered. It is a good insulation but not diy friendly.

 

[bholler]

Can that only been done if it's a straight run, or is it possible to bust out chimneys with offsets?

Yeah we do it all the time. You just have to make sure it is separated well from any other liners and that the chimney can handle it structurally.

 

[bholler]

Though one patient soul here recently did remove his own tiles.

yeah i was impressed

 

[Corey]

For the original question - I think all of those would draft within a whisker of each other. With a "good" 1/4 inch blanket, I expect you could probably touch the outside surface under most any operating conditions. So extra material as pour in or 1/2" keeping in that ~100 degrees of heat is going to give minimal benefit. If you absolutely need it, you might consider extending the flue to 17'6" to make up the difference.

Given those factors, I'd probably opt for the less expensive option...rigid pipe with 1/4" insulation or flex with 1/4". I'd probably stay away from any pour in or 1/2 inch blanket.

 

[bholler]

For the original question - I think all of those would draft within a whisker of each other. With a "good" 1/4 inch blanket, I expect you could probably touch the outside surface under most any operating conditions. So extra material as pour in or 1/2" keeping in that ~100 degrees of heat is going to give minimal benefit. If you absolutely need it, you might consider extending the flue to 17'6" to make up the difference.

Given those factors, I'd probably opt for the less expensive option...rigid pipe with 1/4" insulation or flex with 1/4". I'd probably stay away from any pour in or 1/2 inch blanket.

You do realize that 1/4" wrap does not get you the zero clearance rating. So unless the chimney has the required 1" external or 2" internal clearance to combustibles you need that 1/2" wrap or 1" of pour in. And are you saying that you could touch the outside of the liner with 1/4" insulation? If so i would not recommend that

 

[Berner]

You do realize that 1/4" wrap does not get you the zero clearance rating. So unless the chimney has the required 1" external or 2" internal clearance to combustibles you need that 1/2" wrap or 1" of pour in. And are you saying that you could touch the outside of the liner with 1/4" insulation? If so i would not recommend that

Forgive my ignorance but how is clearance to combustibles a factor? It's running inside terracotta tiles that is inside a stone chimney. I thought clearance to combustibles was not a factor.

Maybe I should of titled the O.P. what will reduce my creosote more? My draft is strong when it's cold. It gets a little sluggish during the shoulder season. But I don't want to extend the liner to 17'6" to improve draft. I feel like the top exposed section of pipe would get really gummed up.

Thanks again for all the help guys your input is valued greatly.

 

[bholler]

Forgive my ignorance but how is clearance to combustibles a factor? It's running inside terracotta tiles that is inside a stone chimney. I thought clearance to combustibles was not a factor.

Is that chimney an internal or external chimney. If it is internal it needs to have a 2" space between the outside of the masonry structure and any combustible material. For an external chimney it is 1". This is because in a chimney fir without that gap there can be enough heat transferred through that masonry to ignite old pyrolized wood. In order to bring it up to code you either need 1/2" wrap or 1" of pour in

Here is the applicable code
http://www.rumford.com/code/clearances.html

 

[Corey]

You do realize that 1/4" wrap does not get you the zero clearance rating. ...

Yeah - I actually remember something like that when I put my liner in... I started with a fireplace...12x12 inch terracotta flue which used to have fire/smoke/sparks of the fireplace DIRECTLY inside it. That terracotta is surrounded by 8+ inches of masonry on the 'thin' side and 24+ inches of masonry on the 'thick' sides...making a chimney bigger than 2 foot x 6 foot overall, which, of course, is surrounded by the wood structure of the house. All this is perfectly fine.

Then... I put a stainless liner inside that terracotta AND an insulation blanket OVER the stainless. NOW it 'technically' doesn't meet the 'clearance to combustibles' because the wood touches the masonry some dozen inches away and the blanket is 1/4" too thin.

So in summary - "by the book" - a chimney which was ''in code" to have smoke and fire directly inside it was made "out of code" by adding a stainless steel liner and an insulation blanket. Sometimes, codes are dumb and you have to let common sense override.

Back to the OP - again, I think all of those are going to be within a whisker of each other with draft or creosote. Some might say the rigid pipe is smooth / easy to clean and less turbulence in the air - so that might win by a few percent. But overall, what does it really mean...you clean the flue at regular intervals and perhaps you get 1-3/4 cups of creosote flake out instead of 2 full cups. The dryness of wood and burning style will contribute WAY more than +/- 1/4" extra insulation.

 

[bholler]

So in summary - "by the book" - a chimney which was ''in code" to have smoke and fire directly inside it was made "out of code" by adding a stainless steel liner and an insulation blanket. Sometimes, codes are dumb and you have to let common sense override.

Did you red the code i posted your chimney was not to code to begin with and adding a stainless liner without the proper insulation does not bring it up to code. And if your chimney is 2' thick and your liner is 12 by 12 you don't have dozens of inches to combustibles. If you choose to ignore the codes in your own house that is up to you but to tell others to do so without giving them the proper info or seeing their setup is irresponsible. But to the op either one of those liners is smooth interior and they will draft very similarly. I prefer the flex because of ease of installation.

 

[Berner]

Is that chimney an internal or external chimney. If it is internal it needs to have a 2" space between the outside of the masonry structure and any combustible material. For an external chimney it is 1". This is because in a chimney fir without that gap there can be enough heat transferred through that masonry to ignite old pyrolized wood. In order to bring it up to code you either need 1/2" wrap or 1" of pour in

Here is the applicable code
http://www.rumford.com/code/clearances.html

Sorry for the late response I was away all weekend. It is a large exterior stone chimney. Doesn't exception 1 say if you have a chimney liner system your masonry chimney can touch combustibles?

Either way I'm definitely going to insulate this new liner somehow. Right now I'm leaning towards Rigid Rhino from Olympia and using a pour in insulation. Sorry to go against your heavy duty flexible suggestion. The benefits of the rigid pipe seem to outweigh the flex. I would rather spend more time during the install and have an easier time cleaning. The suggested ovalized flex would require cleaning from the top down with an oval brush and then more cleaning from the bottom up with a round brush. This two sided approach sounds like a nightmare to me. Especially cleaning from the bottom up. I know cleaning is not often but the small raised hearth and tight fireplace surround make this extra challenging.

Now I have to figure out what is the best choice for pour in insulation.

 

[bholler]

Doesn't exception 1 say if you have a chimney liner system your masonry chimney can touch combustibles?

No it says
Masonry chimneys equipped with a chimney lining system listed and labeled for use in chimneys in contact with combustibles in accordance with UL 1777 and installed in accordance with the manufacturers installation instructions are permitted to have combustible material in contact with their exterior surfaces

In order for a liner system to meet the requirements of ul 1777 for zero clearance it need insulation there is not a liner out there that passed without insulation

The suggested ovalized flex would require cleaning from the top down with an oval brush and then more cleaning from the bottom up with a round brush. This two sided approach sounds like a nightmare to me. Especially cleaning from the bottom up. I know cleaning is not often but the small raised hearth and tight fireplace surround make this extra challenging.

I clean many ovalized liners and have never cleaned that way i generally just use a rotary cleaner. No issues at all

Sorry to go against your heavy duty flexible suggestion.

No reason to apologize at all it is you money and your house. But i am curious what the benefits you see are. Also in your chimney there is no way you will get enough pour in insulation to meet the code requirement. But rigid is a good liner if that is what you choose It will serve you well.

 

[Berner]

No reason to apologize at all it is you money and your house. But i am curious what the benefits you see are. Also in your chimney there is no way you will get enough pour in insulation to meet the code requirement. But rigid is a good liner if that is what you choose It will serve you well.[/QUOTE]


There are lots of options and opinions to make this work. Overall I'm skeptical of flexible. I know everyone says the heavy duty stuff is completely different than the hybrid stuff I currently have in there. Getting over that some say the heavy duty flex is stronger than rigid, some say the opposite.

Either way if I do go heavy wall flex I will need to ovalize the liner to get insulation wrap in because of my terracotta tile size. According to Woodstock if you ovalize the liner you will need to start with a larger pipe size. This means that if the top 16ft out of 17ft are ovalized I will somehow need to get it back down to the 6" round to fit the T. I think the only way to do this is to have some sort of connection between a large oval pipe and regular 6" round. This connection circles back to the "weakest" part of rigid which are the connections.

The other big problem with this ovalized into round is cleaning the liner. Some say rotary brushes will do the entire run. Some say to use oval brushes for the ovalized section and then clean from the bottom up to get the round bottom section. Som say use a smaller 3 to 4 inch metal brush but clean the ovalized liner in two halves working the angle of the brush and rods.

All these seem like complications that could be solved with using a rigid liner and pour in insulation.

Then again if I'm going to go through the hassle of pour in I could also use that on a flex liner.

And I go back to full circle again.

I should have some price quotes from woodland tomorrow. I know I started this all with the philosophy of I don't mind spending money on a permanent solution but if both solutions have their complications then price will have to be factored in. I have a feeling the rigid will be less than half of a heavy wall ovalized but we will see.

Thanks again for all the help. This site and the people on it have been a truly amazing.

 

[bholler]

You do know you can get an oval tee don't you. 7" comes off of that tee and then you reduce to 6" from there. Not an issue at all. I clean many with rotary cleaners or with brushes.

I have a feeling the rigid will be less than half of a heavy wall ovalized but we will see.

Yes probably not half but defiantly less. As long as you are ok with it not meeting the code requirements then go for it.

 

[Berner]

You do know you can get an oval tee don't you. 7" comes off of that tee and then you reduce to 6" from there. Not an issue at all. I clean many with rotary cleaners or with brushes.


Yes probably not half but defiantly less. As long as you are ok with it not meeting the code requirements then go for it.

Oval T does sound nice. It would mean I could run an oval pipe all the way into the T. Currently I have a custom T that was expensive but it's really the only way to get a flexible pipe into the T with the way the lintel and firebox are configured.

 

[bholler]

Currently I have a custom T that was expensive but it's really the only way to get a flexible pipe into the T with the way the lintel and firebox are configured.

Oh that was you i remember that tee. That complicates things for sure. In that case i would have them make you an oval to 6" round adapter and reuse that tee.

 

[Master sweep walt]

Did you red the code i posted your chimney was not to code to begin with and adding a stainless liner without the proper insulation does not bring it up to code. And if your chimney is 2' thick and your liner is 12 by 12 you don't have dozens of inches to combustibles. If you choose to ignore the codes in your own house that is up to you but to tell others to do so without giving them the proper info or seeing their setup is irresponsible. But to the op either one of those liners is smooth interior and they will draft very similarly. I prefer the flex because of ease of installation.

That's great information I am a CSIA. certified sweep and I enjoy seeing information that is put out there that is correct .