Stainless chimney liner for sale at The Chimney Sweep Woodstove Gas Stove Fireplace Cookstove and Barbecue Shop
The Chimney Sweep Online Fireplace, Woodstove, Gas Stove and Barbecue Shop

Forever Flex
Short Length of Forever Flex Liner
Stainless Steel Chimney Liner Kits

Woodburning stove installations often require the installation of a stainless steel liner inside the existing chimney. Forever Flex relining kits offer an easy way to accomplish this, all in one box! Click to read about when and why a stainless liner is required.

Sweepy What's better than a lifetime warranty? How about forever! Forever Flex's unique warranty covers not only the original purchaser for life, but should the original homeowner decide to sell their house, the warranty transfers to the new owner! Click to read the Forever Flex warranty.


Tee Chimney Liner Diagram
 Fireplace Chimney Liner Diagram
Standard Features - Forever Flex Stainless Chimney Liner
  • 316 Ti* Stainless resists flue acids, extreme hot/cold cycles
  • 7-ply seams lock in creosote & flue gases, can't kink or crush
  • Withstands multiple exposures to chimney fire temperatures
  • Light weight, flexible, easy to install
  • Listed to UL 1777 standard by Underwriter Laboratoriess
  • Pre-Insulated Kits available
  • Kits available with tee or insert connector
  • Removable Tee Snout facilitates installation
  • Several top plate options for the same price
  • Top Plate Sealant included in kit
  • Unique Forever Warranty transfers to future home buyers
Fireplace Insert Liner Diagram
Hearth Stove Liner Diagram


*The Ti in 316 Ti stands for Titanium, which is added to the composition of the stainless steel. Titanium stabilizes the alloy at extremely high temperatures of 700 degrees and above, which can occur during a chimney fire. Titanium combines with carbon, preventing the precipitation of chromium carbide from the material, which in turn limits chromium depletion and susceptibility to corrosion. A 316 Ti alloy can be held at higher temperatures longer before sensitization occurs than in a non-stabilized alloy like 304L or 316L.


Sizing Your Chimney Liner

The ideal size for a stainless liner is the same diameter as the exhaust opening on the appliance. If the liner is too small, it may not allow the exhaust volume necessary for efficient operation. If it is too big, it may draft too slowly at startup, and develop too much updraft when it finally heats up.

To read more about flue undersizing, click here.

To read more about flue oversizing, click here.

A possible exception: If the appliance has a 6" flue collar and there isn't room in the existing chimney flue for a 6" liner, consider using a 5.5" liner. For chimneys at least 20' tall, this slight size reduction almost always works.


A Kit for Every Installation

Forever Flex Stainless Tee Liner Drawing A Forever Flex Stainless Tee Liner Drawing B
Wood Stove Liner Kit:
* Rain Cap
* Top Sealer Plate
* Flex Liner
* Tee w/10" Snout, Cap
* Silicone Sealant

5" $420 $435$495 $565$625 $685
5.5"$445 $470 $530$620 $660$740
7" $530 $580$660 $760$850 $940
8" $550 $630$730 $860$960 $1070
Forever Flex Stainless Tee Liner Components

Wood Stove
Liner Kit


Forever Flex Stainless Insert Liner Components

Fireplace Insert
Liner Kit

Forever Flex Stainless Insert Liner Drawing AForever Flex Stainless Insert Liner Drawing B
Fireplace Insert Liner Kit:
* Rain Cap
* Top Sealer Plate
* Flex Liner
* Flue Collar Adapter
* Silicone Sealant

5" $370 $430$490 $540$620 $680
5.5"$370 $420 $490$570 $640$750
7" $440 $520$610 $710$800 $900
8" $450 $540$640 $800$900 $1010
Order or Inquire Button

Note: Liner kit pricing shown includes
residential delivery, Continental US!

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To Insulate, or Not to Insulate?

Our Top Sealer Plates seal so tightly, they virtually prevent the flow of air up the flue around the outside of the liner. This creates "dead air insulation" around the liner, and in most installations in code-approved chimneys, no further insulation is required. There are some instances, however, when additional insulation is recommended or even required. To read about when you should insulate your stainless liner, click here.

If you decide to insulate your liner, we now offer two options: add our Super Wrap insulation to a standard liner kit, or opt for one of our NEW Pre-Insulated liner kits.

Forever Flex Super Wrap Insulation Kit
Super Wrap Insulation  Kits:

* Foil-Backed 1/2" Blanket
* Spray Adhesive
* Metal Tape
* Steel Mesh "Sock"
* Top & Bottom Clamps

Unlike typical ceramic blanket insulation, Super Wrap doesn't cause skin or lung irritation, and is not carcinogenic. Super Wrap is light weight and easy to install.

Insulation Wrap Kit Pricing:

25' 30' 35'
6"$310 $350$380
7" $390 - -
8" $450 - -

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  Forever Flex Pre-Insulated Liner

Pre-Insulated Tee Liner Kit Pricing:

Forever Flex Stainless Tee Liner Drawing A  20'25'30'35'40' Forever Flex Stainless Tee Liner Drawing B
5" $810 $910 $1030$1145 $1320
5.5" $810 $910$1030 $1140$1320
6"$830$930$1040$1150 $1330
7" $1050 $1180 $1270$1450 $1670
8" $1160 $1300 $1520$1730 $1990

Pre-Insulated Insert Liner Kit Pricing:

Forever Flex Stainless Insert Liner Drawing A  20'25'30'35'40' Forever Flex Stainless Insert Liner Drawing B
5" $790 $870 $1020$1090 $1260
5.5" $800 $880$1030 $1090$1260
7" $1010 $1100 $1230$1390 $1600
8" $1120 $1240 $1520$1670 $1910

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Problem: some older inserts have
rectangular or oval exhaust openings.

Old-style fireplace insert with rectangular opening

No way to connect to round liner!
Or..... Is there?

the Rectangle to
Round Insert Adapter Boot

Forever Flex Insert Adapter Boot
Covers rectangular openings
up to 9-1/8" x 14-3/4",
adapts to 6", 7" or 8" round

Sizing your Insert Boot:
Measure the exhaust opening
Insert Opening Measurement Diagram
If A x B < 28".................. 6"
If A x B > 28" and <39"... 7"
If A x B > 39".................. 8"

Order Boot size shown in blue -
Boot Size determines Liner Size

Insert Adapter Boot, 6", 7" or 8" Round
+ $20.00 S&H
Forever Flex Insert Adapter Boot
10-1/8" x 15-3/8" x 5-1/2" Tall
Angled for easy connection to liner
*Item ships Free with Liner Kit

20" Tee Snout
Replaces standard 10" snout
+ $15.00 S&H

Forever Flex Stainless XL Tee Snout

*Item ships Free with Liner Kit

Pulling Cone w/ Rope Eyelet
Helps guide liner through tight offsets
+ $15.00 S&H

Forever Flex Stainless Liner Pulling Cone

*Item ships Free with Liner Kit

Adjustable Low-Profile Offset Box
With removable cleanout panel
+ $20.00 S&H
6"Box: 8"x14"
Height: 2.5"
Offset: 0" - 6"
8"Box: 10"x18"
Height: 3"
Offset: 0" - 8"

Forever Flex Stainless Liner Offset Box
*Item ships Free with Liner Kit


To read about installing a free-standing woodstove or wood hearth stove liner, click here.

To read about installing a wood fireplace insert liner, click here.

To read about installing the insulation wrap kit, click here.

Not sure what length to order? Click here.


Standard Liner & Super Wrap Dimensions  Pre-Insulated Liner Dimensions
Standard Liner Size Diagram
Liner ID
Liner OD
Wrap OD

Before you order a liner kit, please



(20% Restock Charge on Returned Items)
Liner ID
Liner OD
5.5" 6-13/16"
6" 7-5/16"
7" 8-5/16"
8" 9-5/16"
Pre-Insulated Liner Size Diagram



Hi! Tom!
Just wanted to let you know how great the wood stove is working after installing the flex liner kit. My son and I installed it . Because of the heatilator , we had to cut out some of the metal in the center to make enough clearance for the 6" flex liner, but all went smoothly.

Thanks again for your prompt service.

Edwin A Emerson Jr


Q: Hello,
I need your help. I think I got some bad advice from my local dealer. I did my own install of a Hearthstone Homestead stove, and my local dealer advised me to go with 5 inch solid pipe with insulating wrap because the recommended 6 inch pipe with insulation would not fit into the flue tiles lining my chimney. They assured me the difference between a 5 inch and 6 inch pipe was insignificant. The chimney is not too tall; only about 13 feet from smoke shelf to top, and I lined the whole flue and installed a cap. The stove works fine, but it is almost impossible to open the door to add more wood without some smoke wafting into the house. Would I have been better off with a solid 6 inch non-insulated pipe? Can I improve things by extending the length of pipe sticking out of the chimney (lengthening the chimney)? Would a VacuStack help? I would appreciate your opinion.

Vince Roscigno

Sweepy The minimum vent size for a given woodstove model is not arrived at arbitrarily: it is determined during meticulous laboratory testing. This is why Hearthstone states in their brochure, on their website and in the Homestead owners/installation manual that 6" connector pipe and chimney is the smallest size that may be used.

A 6" round liner has a cross-sectional area of 28.28 sq.inches. Your 5" liner has a cross-sectional area of only 19.64 sq. inches, which is a flue size reduction of 30 percent! Further, 13 feet is the absolute minimum chimney height specified in the manual. Minimum means all other factors must be nearly perfect to ensure adequate updraft in a 13 ft. chimney. The combination of flue undersizing and barely-adequate chimney height reads like a recipe for inefficient burn and smokeback into the house.

You can't extend your flue height with liner pipe: lined masonry or insulated manufactured chimney pipe is required above the existing structure, to prevent the tremendous loss of updraft and excessive creosote formation that results when wood exhaust cools in the flue. You could add courses of brick to the chimney to allow extension of your 5" insulated liner within, but in our experience, it would likely require an extreme height addition to compensate for a 30% reduction in liner size.

The Vacu-Stack draft cap works on Bernoulli's principle, and will only function when wind is blowing directly onto it. The rest of the time, it has no effect on chimney draft. The only way we'd recommend a Vacu-Stack to improve your situation is if it is windy all the time where you live.

Had you consulted us prior to your Homestead purchase, we'd have recommended 6" liner with a tight-sealing top plate to provide dead air insulation, and would have advised you that even then, you might have to extend your chimney height to ensure adequate draft, especially during times when flue gas temperatures and/or atmospheric conditions aren't ideal.


I would like to thank you guys very much!!! The insert liner kit worked out perfectly. Easy to install and fit perfectly into the opening on top of my insert.

Saved 2700 dollars by purchasing the stove as well as the liner kit online and doing it myself!!!

Excellent web site lots of great information and insight.

Thanks again.

Arnie Appleby


I appreciate you responding to me so quickly. You shipped my liner quicker then I was expecting, and have answered all my questions in a timely fashion. If I come across any homeowners who need to reline their chimneys, I will recommend your company hands up.

Thanks again for a job well done.

Damien M. Bricka


Q: How do I determine flue length to see how much liner I need? Thanks... I love the info you provide

Kate Pavelle

Sweepy We discuss several techniques to determine flue height in our Sweep's Library. To open that page in a new window, click here.


I am so glad I purchased my Forever Flex Liner Kit from you folks! After going to my local home repair store and seeing the kit they sell, made in China, poorly constructed ducting and one-size-fits-all parts that have to be forced together and then riveted or screwed, at a HIGHER PRICE than you charged me for the far superior Forever Flex kit. I try to buy products made in the USA, not only to support our economy and American Workers but because I believe we can make a quality product in America.

When I came home today, my wife Joanne said "The hand of God left your box from The Chimney Sweep" I had to laugh, but realized it wasn't even 48 hours since we ordered. Impressive! (Great Job by FedEx also) When I inspected the contents for damage, I found none and a very neatly organized kit. All welded parts, adjustable clamps fitting together perfectly without any real effort to a primary snug fit, then secondary holding with a clamp. Your insight on the large size of my chimney was very helpful to get the right top plate for the kit also.

Thanks to all the folks at The Chimney Sweep who work so hard to be The Best!

I will email again when the warranty runs life?

J Sawyer


Thank you so much for the fast response and all the help. The product was very well built and I was very pleased with the shipping and packaging. This is the best on-line transaction I have had.

Thank you again,

Kevin Hall


Got the kit and insulation first thing Tuesday morning (after only ordering it late the previous Friday afternoon) and installed it that day. Had a fire going Wednesday morning and it all worked GREAT. Thank you for Superb service on the phone and Superb delivery time. Instructions were easy to follow (especially after watching the video). A really nice experience from start to finish with The Chimney Sweep.

Thanks again.

Richard Hampton
Ferrisburgh, Vt.


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