Difficult Reline?

[Kurt in MT]

I have a large masonry stone-faced chimney (built in the 1970s) that services a fireplace (large Elco) on my main floor and a wood stove directly underneath in a fully finished walk-out basement. My problem is with the flue servicing the wood stove. From the top I can see that it was constructed by pouring mortar around a galvanized steel pipe stack. The top section ( 2 ft) of the galvanized stack is degraded and broke loose from the mortar (it pulled right out). Below that, the stack looks ok, but may have problems also. There are no protruding screws.

The galvanized stack is 8” as is the connection to the wood stove (marked as “Hurricane“). I have a local chimney expert coming out to do a full camera inspection. He mentioned that it might not be possible to fix/use the existing arrangement (which I understand). He said over the phone that I might be able to make it workable by relining the flue with a 6” flexible stainless liner and updating with a modern 6” stove. This makes sense to me.

I tried to learn more about relining and saw (in posts from this forum) that the flexibility is limited. My flue goes down from the top (not perfectly straight) and then turns to angle the flue to the center of the large chimney (also stone faced masonry downstairs). The angle might be about 45 degrees or so. Then, it turns at the very end to finish with an 8” horizontal hole in the center of the chimney. Obviously, this is a quirky flue. It has been a pain to clean, because cleaning requires detaching the stove to pull out the debris (but I am ok with that).

The reliner/updated stove idea is appealing to me. Given the relatively tight squeeze and the contortions of the flue, I thought the mixed insulating compound might do the trick. My biggest concern is that the twists and turns of the existing 8” opening might not work if the 6” liner lacks enough flexibility. I am looking at getting a Woodstock stove, and they sell the Forever Flex 316 liners. The manufacture’s website does not give any useful information about the degree of flexibility, but I did notice that they list a “new product“ called “Premium Forever Flex” which they say is more flexible (and more lightweight). I don’t know if it is suitable.

Apologies for this long winded intro, but my question is whether the reline with the twists and turns sounds doable for the flexible stainless products and whether anyone can suggest a liner brand/type that is safe, suitable and flexible enough for this project. Any other thoughts/observations are welcome.

Many thanks

Kurt in MT

 

[Hearthside]

I have a large masonry stone-faced chimney (built in the 1970s) that services a fireplace (large Elco) on my main floor and a wood stove directly underneath in a fully finished walk-out basement. My problem is with the flue servicing the wood stove. From the top I can see that it was constructed by pouring mortar around a galvanized steel pipe stack. The top section ( 2 ft) of the galvanized stack is degraded and broke loose from the mortar (it pulled right out). Below that, the stack looks ok, but may have problems also. There are no protruding screws.

The galvanized stack is 8” as is the connection to the wood stove (marked as “Hurricane“). I have a local chimney expert coming out to do a full camera inspection. He mentioned that it might not be possible to fix/use the existing arrangement (which I understand). He said over the phone that I might be able to make it workable by relining the flue with a 6” flexible stainless liner and updating with a modern 6” stove. This makes sense to me.

I tried to learn more about relining and saw (in posts from this forum) that the flexibility is limited. My flue goes down from the top (not perfectly straight) and then turns to angle the flue to the center of the large chimney (also stone faced masonry downstairs). The angle might be about 45 degrees or so. Then, it turns at the very end to finish with an 8” horizontal hole in the center of the chimney. Obviously, this is a quirky flue. It has been a pain to clean, because cleaning requires detaching the stove to pull out the debris (but I am ok with that).

The reliner/updated stove idea is appealing to me. Given the relatively tight squeeze and the contortions of the flue, I thought the mixed insulating compound might do the trick. My biggest concern is that the twists and turns of the existing 8” opening might not work if the 6” liner lacks enough flexibility. I am looking at getting a Woodstock stove, and they sell the Forever Flex 316 liners. The manufacture’s website does not give any useful information about the degree of flexibility, but I did notice that they list a “new product“ called “Premium Forever Flex” which they say is more flexible (and more lightweight). I don’t know if it is suitable.

Apologies for this long winded intro, but my question is whether the reline with the twists and turns sounds doable for the flexible stainless products and whether anyone can suggest a liner brand/type that is safe, suitable and flexible enough for this project. Any other thoughts/observations are welcome.

Many thanks

Kurt in MT

Try a light heavyflex liner (hybrid) They take turns very well! Also attach a pulling cone on the end so you can have someone pull the liner down while someone feeds it down from the top. These liners cost a little more but well worth the cost. Steer away from the premium light weight liner. Very thin walled for wood burning.

 

[Kurt in MT]

Very helpful! The light heavyweight hybrid looks like an excellent solution. I particularly like that it is not on the light weight end of the toughness scale. We burn Douglas Fir (best option here) and the ability to stand up well to cleaning is a big deal for me. I will try to get an estimate for professional installation, then weigh vs. DYI (where I live, getting quality work done by someone reasonably close by is often a challenge). Many thanks!

 

[Kurt in MT]

Try a light heavyflex liner (hybrid) They take turns very well! Also attach a pulling cone on the end so you can have someone pull the liner down while someone feeds it down from the top. These liners cost a little more but well worth the cost. Steer away from the premium light weight liner. Very thin walled for wood burning.

Hello

Here is the update. The local chimney guy (only one close enough to do the job) says he has used all kinds of liners and they all are about the same in terms of flexibility. He is very pessimistic that he can help if there is a 45 degree angle and, basically, doesn’t want to try. Nevertheless, he seems to be knowledgeable about code requirements and safety, so I am going to have him come out for a level 2 camera inspection anyway. He might have some good observations from that standpoint. The reality is that my area is really busy with people building/remodeling big dollar vacation homes and ski lodges......he has more work than he knows what to do with (and probably doesn’t need the aggravation of my small job challenge).

So, after the inspection, my plan B is looking into DYI. I thought I might try to buy a cone and a length of test liner (maybe six feet) and do a trial to see if the hybrid liner material will pass through ok. (I would just see if it can pull all the way through, exiting the bottom). Does the trial idea make sense to you?

One comment the guy made concerns me though. When I asked about using the insulating mix, he expressed concern that there might not be enough clearance to ensure proper spacing between the old existing liner (galvanized in mortar) and the new. I don’t understand that comment at all. The whole chimney is solid masonry, about 6 ft wide by about 2-1/2 deep, with nothing combustible within that footprint. My understanding (perhaps wrong) is that the new liner would work inside the existing flue no matter the clearance , and that the insulation was about improving performance from a creosote standpoint (assuming the old liner is clear of creosote before the installation). Is that correct?

Any follow up thoughts from you (or others) would be greatly appreciated.

 

[Hearthside]

Hello

Here is the update. The local chimney guy (only one close enough to do the job) says he has used all kinds of liners and they all are about the same in terms of flexibility. He is very pessimistic that he can help if there is a 45 degree angle and, basically, doesn’t want to try. Nevertheless, he seems to be knowledgeable about code requirements and safety, so I am going to have him come out for a level 2 camera inspection anyway. He might have some good observations from that standpoint. The reality is that my area is really busy with people building/remodeling big dollar vacation homes and ski lodges......he has more work than he knows what to do with (and probably doesn’t need the aggravation of my small job challenge).

So, after the inspection, my plan B is looking into DYI. I thought I might try to buy a cone and a length of test liner (maybe six feet) and do a trial to see if the hybrid liner material will pass through ok. (I would just see if it can pull all the way through, exiting the bottom). Does the trial idea make sense to you?

One comment the guy made concerns me though. When I asked about using the insulating mix, he expressed concern that there might not be enough clearance to ensure proper spacing between the old existing liner (galvanized in mortar) and the new. I don’t understand that comment at all. The whole chimney is solid masonry, about 6 ft wide by about 2-1/2 deep, with nothing combustible within that footprint. My understanding (perhaps wrong) is that the new liner would work inside the existing flue no matter the clearance , and that the insulation was about improving performance from a creosote standpoint (assuming the old liner is clear of creosote before the installation). Is that correct?

Any follow up thoughts from you (or others) would be greatly appreciated.

Hello

Yes, a small test section would be helpful to see what your up against as far as passing the liner down. I have not seen to many offsets that the hybrid liners could not make. Typically offsets are there to go around something else ie: another fireplace. Or to transition the chimney to another point other than vertical. Even at that they should not be that steep of a offset as this will affect the performance of the fireplace.( Less draft)

A camera inspection is a good idea! This will shed some light on what you are up against. There may be a surprise in there that you cant even see. And in technical terms. NFPA 211 requires a level 2 inspection before relining a chimney! As far a insulation, the pour down insulation is not a good idea in a chimney with a offset. The material has to be at least 1 inch thick to get the zero clearance, That will be hard to do with a offset! Part of the liner would actually be laying on the old flue liner. Making it difficult to get the mix all around the liner. Insulation is a good idea and is required in most cases by the liner manufacturers when burning wood. There is one company that states if you can prove your chimney is built to NFPA 211 that insulation is not even needed. Insulation provides a layer of protection. It helps keep the liner hot so creosote does not build up as much. The flue will warm up faster and draft will establish quicker This is helpful in colder climates. And, in the event of a chimney fire ,it will keep heat from transferring to the adjacent combustible materials if present. A 1/2 inch of foil face ceramic insulation is another option you have. Wrapping the liner with insulation cuts down on its flexibility. And the 1/2 wrap may keep it from passing the offset. A 1/4 wrap of insulation provides 1 inch of clearance to combustibles. However, this may be the only means of providing a insulation factor and keep the liner flexible enough to pass down! Just a little extra info for. Sorry if you already knew some of this. Good Luck! Let me know how it turns out!

 

[Kurt in MT]

Hello

Yes, a small test section would be helpful to see what your up against as far as passing the liner down. I have not seen to many offsets that the hybrid liners could not make. Typically offsets are there to go around something else ie: another fireplace. Or to transition the chimney to another point other than vertical. Even at that they should not be that steep of a offset as this will affect the performance of the fireplace.( Less draft)

A camera inspection is a good idea! This will shed some light on what you are up against. There may be a surprise in there that you cant even see. And in technical terms. NFPA 211 requires a level 2 inspection before relining a chimney! As far a insulation, the pour down insulation is not a good idea in a chimney with a offset. The material has to be at least 1 inch thick to get the zero clearance, That will be hard to do with a offset! Part of the liner would actually be laying on the old flue liner. Making it difficult to get the mix all around the liner. Insulation is a good idea and is required in most cases by the liner manufacturers when burning wood. There is one company that states if you can prove your chimney is built to NFPA 211 that insulation is not even needed. Insulation provides a layer of protection. It helps keep the liner hot so creosote does not build up as much. The flue will warm up faster and draft will establish quicker This is helpful in colder climates. And, in the event of a chimney fire ,it will keep heat from transferring to the adjacent combustible materials if present. A 1/2 inch of foil face ceramic insulation is another option you have. Wrapping the liner with insulation cuts down on its flexibility. And the 1/2 wrap may keep it from passing the offset. A 1/4 wrap of insulation provides 1 inch of clearance to combustibles. However, this may be the only means of providing a insulation factor and keep the liner flexible enough to pass down! Just a little extra info for. Sorry if you already knew some of this. Good Luck! Let me know how it turns out!

Thanks so much! This information is incredibly helpful. It sounds to me that I might be better off and safer running a new class A chimney to service the wood stove downstairs. I am getting a new stove either way so the added cost of the chimney (vs a problematic reline ) sounds like money well spent.

 

[bholler]

Thanks so much! This information is incredibly helpful. It sounds to me that I might be better off and safer running a new class A chimney to service the wood stove downstairs. I am getting a new stove either way so the added cost of the chimney (vs a problematic reline ) sounds like money well spent.

I would let him take a look at it. It could be possible and he seems to know what he is talking about. Other than saying all liners are about the same flexibility. The midweight liners like Olympias hybrid hearthside referenced are much more flexible.

 

[Dmitry]

Just wanted to share my experience. I recently installed 23 feet of heavy duty liner inside my 13 by 13 clay chimney with crazy twist in a middle of the run. The liner was super flex 316, real heavy and durable. I put insulation wrap on it required by code. It got stuck halfway trough. Three guys couldn't pull it up or push it down. The pulling cone was secured with three screws on bottom side, but it couldn't move a bit with all my strength and weight pulling down. I was about to quit, cut the liner from the top and close the chimney forever. Before doing that i decided to try a winch to pull the rope. I've secured a brace to the floor with masonry screws and start pulling inch by inch going to the roof and trying to twist it . Couple hors later I was able to pull it all the way. I can tell that the rope was about to snap couple times, I'm sure that cone would not stay there if not secured by screws.

 

[Hearthside]

Just wanted to share my experience. I recently installed 23 feet of heavy duty liner inside my 13 by 13 clay chimney with crazy twist in a middle of the run. The liner was super flex 316, real heavy and durable. I put insulation wrap on it required by code. It got stuck halfway trough. Three guys couldn't pull it up or push it down. The pulling cone was secured with three screws on bottom side, but it couldn't move a bit with all my strength and weight pulling down. I was about to quit, cut the liner from the top and close the chimney forever. Before doing that i decided to try a winch to pull the rope. I've secured a brace to the floor with masonry screws and start pulling inch by inch going to the roof and trying to twist it . Couple hors later I was able to pull it all the way. I can tell that the rope was about to snap couple times, I'm sure that cone would not stay there if not secured by screws.

What size liner did you use? I usually remove flue tiles to make room if needed.

 

[Dmitry]

What size liner did you use? I usually remove flue tiles to make room if needed.

6' Liner with wrap insulation

 

[bholler]

6' Liner with wrap insulation

And you had trouble getting that through a 13x13?

 

[Dmitry]

And you had trouble getting that through a 13x13?

Yeah, I know, it sounds strange. It had two offsets close to each other.

 

[bholler]

Yeah, I know, it sounds strange. It had two offsets close to each other.

Ok those had to be really bad offests

 

[Kurt in MT]

Hello

Yes, a small test section would be helpful to see what your up against as far as passing the liner down. I have not seen to many offsets that the hybrid liners could not make. Typically offsets are there to go around something else ie: another fireplace. Or to transition the chimney to another point other than vertical. Even at that they should not be that steep of a offset as this will affect the performance of the fireplace.( Less draft)

A camera inspection is a good idea! This will shed some light on what you are up against. There may be a surprise in there that you cant even see. And in technical terms. NFPA 211 requires a level 2 inspection before relining a chimney! As far a insulation, the pour down insulation is not a good idea in a chimney with a offset. The material has to be at least 1 inch thick to get the zero clearance, That will be hard to do with a offset! Part of the liner would actually be laying on the old flue liner. Making it difficult to get the mix all around the liner. Insulation is a good idea and is required in most cases by the liner manufacturers when burning wood. There is one company that states if you can prove your chimney is built to NFPA 211 that insulation is not even needed. Insulation provides a layer of protection. It helps keep the liner hot so creosote does not build up as much. The flue will warm up faster and draft will establish quicker This is helpful in colder climates. And, in the event of a chimney fire ,it will keep heat from transferring to the adjacent combustible materials if present. A 1/2 inch of foil face ceramic insulation is another option you have. Wrapping the liner with insulation cuts down on its flexibility. And the 1/2 wrap may keep it from passing the offset. A 1/4 wrap of insulation provides 1 inch of clearance to combustibles. However, this may be the only means of providing a insulation factor and keep the liner flexible enough to pass down! Just a little extra info for. Sorry if you already knew some of this. Good Luck! Let me know how it turns out!

Well, the conclusion was that the reline (6“ insulated flex in an 8” old flue with severe twist/turns) just would not work. So plan B is a new class A chimney. To make it work for the pass through in my upper level requires repositioning (with a new hearth etc) the stove to a corner (using closet space for the pass through). Unfortunately, it requires cutting/boxing a floor joist, but that allows a straight and easy chimney run. I asked the chimney guy for an estimate on the chimney install only (assuming I provide the completely level and aligned ceiling and attic boxes). His response was disappointing (but not unexpected).....20% markup on parts, full labor rate for travel plus $3 per mile (I live in a remote area) for two workers plus time spent for the job @125 per hour each. So, I have ordered the parts and have a DYI project. I have all the tools and good enough skills handle (including laser level/plumb bob). In the end, I am actually pleased with the outcome I was forced into.....better stove position, a new, safer and easier cleaning chimney and upwards of $3k saved.

 

[begreen]

So plan B is a new class A chimney. To make it work for the pass through in my upper level requires repositioning (with a new hearth etc) the stove to a corner (using closet space for the pass through).

Explain that plan in detail. Long horizontal sections of chimney can be very problematic. Sketches of the plan and some pics are very helpful.

 

[Kurt in MT]

Explain that plan in detail. Long horizontal sections of chimney can be very problematic. Sketches of the plan and some pics are very helpful.

Sure! Thanks for the opportunity! I don’t have a sketch , but it is a corner stove position in a fully-finished, insulated walkout basement (the stove corner is on the underground side).

Starting at the bottom. Woodstock keystone stove (with heat shield) with 20 inch corner clearance from nearest side walls, oversized hearth on concrete floor. 18 inch stove pipe (all double Duravent DVL) up from stove top to two 45s joined by telescope. Telescope down to 45 from square ceiling chimney box (24 high....using DuraTech). Horizontal run from center of chimney to center of stove opening is about 22”. The ceiling position to nearest wall is 4.5“, wall to box (providing 6.5“ wall clearance to connecting pipe). Here, I do not have much flexibility because more wall clearance would translate into interference with my front door on the next level. For extra protection, I am going to add a wall heat shield on the wall (just for the stove pipe leaving the ceiling box) using a 24”x24” piece of stainless on 1” ceramic spacers. The chimney travels straight up through the lost closet space on the upper level (boxing in with new frame, drywall....more than 2” clearance from chimney) to the radiation shield in the closet ceiling/attic opening, topped with insulation shield and top collar. From there, straight up through the roof (no truss anywhere near), flashing, then cap.

The chimney portion is 18’. I would allow the ceiling box to extend about 9” down from the ceiling. So the overall vertical of the chimney and stove pipe is about 22.5ft. That puts the very top at about 3’ above the highest point of my roof. I will be using the rooftop bracing, and I plan on attaching two additional chimney braces, one about half way up the closet, the other in the attic, down a foot or two from the roof (the braces from Duravent, attached to new framing more than 2” away from the chimney). I live in a high altitude (5500ft), high wind area. My old stove had excellent draft with a chimney about a foot lower and a strange configuration of two 45s in the chimney and one 90 above the stove). We also get tremors occasionally (not that far from Yellowstone), so I thought the extra braces would be a good idea. I am also using a DuraTech locking band at each chimney pipe-to-pipe connection.

There is no inspection required or available here, so code compliance is up to me. I bought the online current NFPA 211 to read and re-read. I studied the installation instructions (stove and the Duravent products) and will endeavor to keep everything completely “by the book”. I am good with tolerances (worked as a machinist many years ago), so maintaining clearances is not a problem.

I would appreciate any thoughts or comments!

 

[begreen]

22" horiz. is ok. Sketch this out on a piece of paper and take a picture with a cell phone and post. This may be overengineered using the wrong components. For example, a standard ceiling support should work. The 24" tall box support box is usually for cathedral ceilings.

 

[Kurt in MT]

22" horiz. is ok. Sketch this out on a piece of paper and take a picture with a cell phone and post. This may be overengineered using the wrong components. For example, a standard ceiling support should work. The 24" tall box support box is usually for cathedral ceilings.

I was going with the 24 square box because the 11 box would not clear the floor with hardwood flooring and the required drop from the ceiling of at least 3”. Unless there is some danger caused, I want the box to pass through the floor completely. I prefer the square box because the framing on all sides will be more solid than the round. Any thing I can do to make the chimney more solid is useful....the wind gusts here literally rip shingles off roofs and siding off houses if they are just installed to mfg. spec.



The closet above (96”x22”) straddles the downstairs side wall. So, I need to reframe the closet section containing the chimney, moving the upstairs wall about 4” toward the front door. This leaves good clearance for door operation, but the side wall to box clearance downstairs is only 4.5”. With the 2” clear inside the box, that works with the double wall connecting pipe (minimum 6” clearance) but just barely (hence the heat shield). The chimney also is positioned about 20” from the front wall (the wall where the the door is) to be clear of trusses above).

Adding up the chimney height, it is just under 15’ to the highest roof point. I added 3’ to get my 18’ overall chimney height. The chimney actually penetrates the roof at a lower position (22” below the highest point), so my stack will be
about 5’ above the roof at that spot.

 

[begreen]

Thanks that helps a lot. Technically double-wall stove pipe is ok if the clearance is 6" or higher, but I understand if you want to shield it for increased peace of mind. The 45º offset off the stove is fine. The "Box 9" at the ceiling penetration is a little confusing. What does that mean? Normally that location would have a simple, ceiling support box. The closet ceiling penetration would have a firewall installed with an attic insulation shield on top.

Have you picked out a brand and type of chimney pipe yet?

 

[Kurt in MT]

Thanks that helps a lot. Technically double-wall stove pipe is ok if the clearance is 6" or higher, but I understand if you want to shield it for increased peace of mind. The 45º offset off the stove is fine. The "Box 9" at the ceiling penetration is a little confusing. What does that mean? Normally that location would have a simple, ceiling support box. The closet ceiling penetration would have a firewall installed with an attic insulation shield on top.

Have you picked out a brand and type of chimney pipe yet?

I am using DuraTech for the chimney and their DVL double wall stove pipe. The “9” refers to my planned level of the drop of bottom of the ceiling box (down from the ceiling). The instructions for the box say 3” minimum for this. Because I have plenty of vertical chimney, I arbitrarily picked 9” so the top of stack on the roof would not be overly high for cap removal and cleaning. I really appreciate your brain power on this!

 

[Kurt in MT]

I am using DuraTech for the chimney and their DVL double wall stove pipe. The “9” refers to my planned level of the drop of bottom of the ceiling box (down from the ceiling). The instructions for the box say 3” minimum for this. Because I have plenty of vertical chimney, I arbitrarily picked 9” so the top of stack on the roof would not be overly high for cap removal and cleaning. I really appreciate your brain power on this!

And yes, the ceiling pass through above the closet will go through the recommended radiant shield, topped with an insulation guard and capped with a collar.

 

[Kurt in MT]

I am using DuraTech for the chimney and their DVL double wall stove pipe. The “9” refers to my planned level of the drop of bottom of the ceiling box (down from the ceiling). The instructions for the box say 3” minimum for this. Because I have plenty of vertical chimney, I arbitrarily picked 9” so the top of stack on the roof would not be overly high for cap removal and cleaning. I really appreciate your brain power on this!

Well, the chimney installation is done ! I still have a lot of drywall finishing to do (I basically had to use closet space on the first floor for the passage way, requiring that interior area to be completely reframed). I wanted to err on the side of safety, so my tightest clearances to combustibles are, in effect, the 2 inches maintained by the duravent ceiling box and the duravent attic shield pass throughs. The rest is 3 inches, plus.

I have one more question if you don’t mind. On the first floor, the reframed chimney passage is near (behind) my front door. Right now, the chimney is hidden behind 5/8 fireguard drywall. FYI, I also painted the entire interior of the new chimney box with Firetect WD-102 flame retardant....just for peace of mind ). I was thinking about putting in two vents, one near the floor, one closer to the ceiling. This would allow some warmth to flow into the door area. But the main reason is that it would allow me to monitor the temperature and general status of things inside the chimney enclosure. I guess the downside is that I lose a little flue gas temperature which theoretically would allow for more creosote and, perhaps, lose some level of fireproofing for the box (less containment).

The chimney is straight, 18 feet. About 10-1/2 feet of that is in insulated house space, with about 7-1/2 in the attic (above the insulation) and outside above the roof level.

Do you have a view on the advisability of adding the vents?

 

[kennyp2339]

Vents are not really needed, the outside of the class A pipe will only get warm to the touch, more or less its nullified and not really worth the effort to cut in vents, but if your inclined to do so, then go ahead.

 

[SpaceBus]

You have probably done a better job than most "professionals" and you should feel good about the performance and safety of the installation.

 

[Mutineer]

Post your skills and pics on Facebook Marketplace and hire yourself out for other installs/retrofits in the area! Sounds like you would be swamped with business. A shame to let your level of expertise and now experience go to waste.