Liner: DuraFlex, Lifetime, etc.

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vap0rtranz

New Member
Feb 22, 2020
24
Chicago
I'll be installing a chimney liner. Opinions on DuraFlex vs Lifetime?

I've read several posts here about liners. Most recommend heavy/medium weight but I cannot find where manufacturers state the weights of their liners. Where is this info?

Also, some think DuraVent's 304 is too cheaply made. What about Lifetime? Their liner is even cheaper than DuraVent. I'm also looking at DuraFlexSS.

Finally, I'm surprised more folks don't recommend smooth-wall liners. I'd like to go smooth-wall + insulated.

Details on my install: it's a masonry chimney sitting dead center of the house. I got it professionally inspected. My chimney guys recommended a liner, probably to match the stove's 6" pipe. I'm hooking up a Woodstock 205 Fireview that has 6" stovepipe. There's 21' of chimney from the stovepipe tee with 8" diameter flue. No fireplace was ever installed; it's straight up to the chimney cap after the tee. So I'm hoping the install will be relatively straight forward for DIY.
 
Last edited:

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
I'll be installing a chimney liner. Opinions on DuraFlex vs Lifetime?

I've read several posts here about liners. Most recommend heavy/medium weight but I cannot find where manufacturers state the weights of their liners. Where is this info?

Also, some think DuraVent's 304 is too cheaply made. What about Lifetime? Their liner is even cheaper than DuraVent. I'm also looking at DuraFlexSS.

Finally, I'm surprised more folks don't recommend smooth-wall liners. I'd like to go smooth-wall + insulated.

Details on my install: it's a masonry chimney sitting dead center of the house. I got it professionally inspected. My chimney guys recommended a liner, probably to match the stove's 6" pipe. I'm hooking up a Woodstock 205 Fireview that has 6" stovepipe. There's 21' of chimney from the stovepipe tee with 8" diameter flue. No fireplace was ever installed; it's straight up to the chimney cap after the tee. So I'm hoping the install will be relatively straight forward for DIY.
Heavy wall and mid weight liners are smooth wall. The lightweight smooth wall that is double layer is just junk which is why it isn't recommend.
 

vap0rtranz

New Member
Feb 22, 2020
24
Chicago
Heavy wall and mid weight liners are smooth wall.
OK, good to know.

If I'm reading DuraVent's specs right, I'd want the .010" DuraFlex SW.

Materials and Construction
DuraFlex Pro:
Single-wall .005″ 316 stainless steel.
DuraFlex SW: Single-wall .005″ overlapped 316 stainless steel (totalling .010″). Overlapped to create smooth inner wall.
DuraFlex 316 & 304: Single-wall .005” 316 or 304 stainless steel.

 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
OK, good to know.

If I'm reading DuraVent's specs right, I'd want the .010" DuraFlex SW.

Materials and Construction
DuraFlex Pro:
Single-wall .005″ 316 stainless steel.
DuraFlex SW: Single-wall .005″ overlapped 316 stainless steel (totalling .010″). Overlapped to create smooth inner wall.
DuraFlex 316 & 304: Single-wall .005” 316 or 304 stainless steel.

No the sw is the crap you absolutely don't want. Mid weight is made from a single piece of . 010 stainless and heavy wall is . 014 to . 016 thick steel
 

vap0rtranz

New Member
Feb 22, 2020
24
Chicago
No the sw is the crap you absolutely don't want.

Ah, looks like I'll be avoiding all DuraFlex. Only DuraVent rigid "DuraLiner" product has those thicknesses.

I wanted to avoid rigid liner because it looks to be more exacting for a DIYer, but never tried installing this before so what do I know.

Lifetime claims to have thicker flex liners but don't say what the measures really are. https://lifetimechimneysupply.com/heavyweight-flex-chimney-liner
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
Ah, looks like I'll be avoiding all DuraFlex. Only DuraVent rigid "DuraLiner" product has those thicknesses.

I wanted to avoid rigid liner because it looks to be more exacting for a DIYer, but never tried installing this before so what do I know.

Lifetime claims to have thicker flex liners but don't say what the measures really are. https://lifetimechimneysupply.com/heavyweight-flex-chimney-liner
Yes that is the type of liner I use for wood. I know absolutely nothing about that company but that type of liner is good
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,791
South Puget Sound, WA
Ah, looks like I'll be avoiding all DuraFlex. Only DuraVent rigid "DuraLiner" product has those thicknesses.

I wanted to avoid rigid liner because it looks to be more exacting for a DIYer, but never tried installing this before so what do I know.

Lifetime claims to have thicker flex liners but don't say what the measures really are. https://lifetimechimneysupply.com/heavyweight-flex-chimney-liner
@Hogwildz did a DIY with DuraLiner. It is not hard. The main thing is to have all necessary and proper supplies on hand and a system for holding the liner in place as the next section is riveted on.
 

CanFireman

Member
Mar 23, 2018
15
Canada
No the sw is the crap you absolutely don't want. Mid weight is made from a single piece of . 010 stainless and heavy wall is . 014 to . 016 thick steel
Come again? That comment seems a bit harsh. What are you basing your opinion on?

In the end, flex comes in good, better, and best. Not everybody has the same budget. If money is no object, you can find liner product made like a tank, but will be overkill for majority of homeowners.

DuraFlex 316 is certainly an improvement over DuraFlex 304. Titanium adds extra corrosion resistance. Important for applications where appliance is used regularly for primary heating or if coal is being burned.

DuraFlex Pro is 316, and much heavier than standard DuraFlex 316.

Smoothwall is simply another option over standard corrugated flex. Two-ply stainless flex with NO corrugations on the inner wall. This improves flow and minimizes crevices where soot and creosote can hide.

For even heavier product, go Ventinox. Duraliner is great too. Rigid, insulated relining product. Flexible sections are offered for passing up through smoke-shelf.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,791
South Puget Sound, WA
Smoothwall is simply another option over standard corrugated flex. Two-ply stainless flex with NO corrugations on the inner wall. This improves flow and minimizes crevices where soot and creosote can hide.
The 2ply smoothwall stuff tends to pucker and fishmouth over time. Sometimes the inner ply does this even during installation. There are several examples posted in this forum. That's why it's being called "crap".
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
Come again? That comment seems a bit harsh. What are you basing your opinion on?

In the end, flex comes in good, better, and best. Not everybody has the same budget. If money is no object, you can find liner product made like a tank, but will be overkill for majority of homeowners.

DuraFlex 316 is certainly an improvement over DuraFlex 304. Titanium adds extra corrosion resistance. Important for applications where appliance is used regularly for primary heating or if coal is being burned.

DuraFlex Pro is 316, and much heavier than standard DuraFlex 316.

Smoothwall is simply another option over standard corrugated flex. Two-ply stainless flex with NO corrugations on the inner wall. This improves flow and minimizes crevices where soot and creosote can hide.

For even heavier product, go Ventinox. Duraliner is great too. Rigid, insulated relining product. Flexible sections are offered for passing up through smoke-shelf.
I am basing my opinion on many years of experience working with and inspecting liners. The 2 ply stuff just doesn't hold up well at all. I see no reason to spend more money on a product that in my experience is far less durable.

In addition if the liner will only be used for wood and there is no corrosive residue from coal oil etc in the old chimney there is no benifit to paying extra for 316. 304 resists corrosion from wood just as well.

Ventinox is the same thickness as regular light wall it just has a welded seam. If you really want more durable midweight or heavy wall is what you want. Or rigid.
 

Hogwildz

Minister of Fire
I used DuraLiner insulated double wall rigid, with 5' of flex though the smoke shelf to the stove outlet, love the stuff. Easy breathing, easy to clean, no issues in 14 years or so. Installed by myself, not that hard.
 

CanFireman

Member
Mar 23, 2018
15
Canada
I have DuraFlex 304 stainless flex connected to a Enviro Kodiak 1200 insert. Used every day through the winter. Going on 10+ years now. Has held up fine for me.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
I have DuraFlex 304 stainless flex connected to a Enviro Kodiak 1200 insert. Used every day through the winter. Going on 10+ years now. Has held up fine for me.
What type of dura flex is it? 10 years is fine but when I put a liner in for someone I am looking for a 30 year life
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,667
central pa
Will get back to you in 20 years.
Regular light wall is just fine. It works well for many people. It just isn't as durable as mid or heavy wall. I have just seen way too many problems with the 2 ply stuff to ever recommend it to anyone. But regardless I seriously doubt that light wall will last 30 years if used for full time heat. That is way beyond the manufacturers projected lifespan