For a 6-inch stainless chimney liner kit, 35 feet long, my best overall pick is the Rockford Chimney Supply 316 Stainless Steel Flexible Kit with Blanket Insulation, which combines the requested length and diameter with insulation. The Chim Cap Forever Vent 316L kit is a standout for shoppers who want another flexible 35-foot option, while Rockford’s smooth-wall 35-foot kits suit buyers prioritizing a smoother interior. The main tradeoffs are flexible versus smooth-wall construction, whether the kit includes insulation, and whether your installation needs a tee or insert components. Several listings are 25 feet long, so matching length to the measured chimney matters as much as choosing a brand. Read on for the full comparison and guidance on narrowing the options to your installation.
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Key Takeaways
- The Rockford 316 flexible kit with blanket insulation most closely matches the exact 6-inch, 35-foot search while adding insulation to the package.
- Flexible and smooth-wall designs serve different installation priorities; the listings offer both, so the right choice depends on the chimney route and installation plan.
- Tee and insert kits are not interchangeable by name alone; compare the included configuration with your appliance connection and existing chimney setup.
- Length is a clear dividing line in this roundup: several Fireside and Rockford listings are 25 feet, rather than the requested 35 feet.
- Insulation is a recurring differentiator among Rockford listings, but buyers should confirm the kit contents and installation requirements before choosing.
| inch stainless chimney liner kit 35 ft | Material | Warranty |
|---|---|---|
| Rockford Chimney Supply 316 St | 316 stainless steel | — |
| Chim Cap Forever Vent Flexible | 316L stainless steel | — |
| Fireside Chimney Supply FireSa | 316 stainless steel | — |
| Rockford Chimney Supply 316 St | 316 stainless steel | Lifetime, transferable |
| Rockford Chimney Supply Stainl | 316 stainless steel | Lifetime |
| Smooth Wall Chimney Liner Kit | 316L stainless steel | Lifetime |
| Rockford Chimney Supply Smooth | — | Lifetime |
| Rockford Chimney Supply Stainl | 316 stainless steel | — |
| Fireside Chimney Supply FireSa | 316 stainless steel | — |
| Rockford Chimney Supply 316 St | 316 stainless steel | Transferable lifetime |
| Rockford Chimney Supply 316 St | 316 stainless steel | Transferable lifetime warranty |
| Rockford Chimney Supply 316 St | 316 stainless steel | — |
| Rockford Chimney Supply 316 St | 316 stainless steel | Transferable lifetime warranty |
More Details on Our Top Picks
Rockford Chimney Supply 316 Stainless Steel Flexible Chimney Liner Kit, 6 Inch x 35 Feet, with Blanket Insulation
This Rockford kit pairs a 6-inch, 35-foot flexible liner with a blanket insulation kit, making it a direct fit for buyers who need the specified length and want insulation included rather than sourced separately. Its 316 stainless steel construction and UL1777 and ULCS635 listings give it a clear standards-based advantage over kits whose provided details do not specify those listings. Compared with the Chim Cap Forever Vent, which supplies a tee and rain-capped top plate, this option puts more emphasis on insulation; the listed product details do not identify the same range of included termination and connection parts. The tradeoff is a firm installation boundary: it is intended for masonry chimneys. I’d choose it for an insulated masonry relining job, but not where the chimney type falls outside that scope.
Pros:- 316 stainless steel liner
- Includes blanket insulation kit and installation items
- UL1777-listed in the USA and ULCS635-listed in Canada
- Matches the 6-inch by 35-foot size in the roundup
Cons:- Specified for installation inside masonry chimneys
- Provided details do not enumerate the included connection and termination components
- The insulation package may not suit buyers who need an uninsulated liner
Best for: Homeowners relining a masonry chimney who want a 35-foot, 6-inch liner and blanket insulation in the same kit.
Not ideal for: Buyers lining a non-masonry chimney or those who need a clearly specified tee, top plate, and cap package.
- Material:316 stainless steel
- Diameter:6 inches
- Length:35 feet
- Insulation:Blanket insulation kit included
- Certification:UL1777 (USA), ULCS635 (Canada)
- Installation:Inside a masonry chimney
Our verdict“Choose this for a masonry chimney when you want a 35-foot 316 stainless liner with blanket insulation included.”
Chim Cap Forever Vent Flexible Chimney Liner Kit, 316L Stainless Steel, 6 in x 35 ft
The Chim Cap Forever Vent earns its place through a clearly listed set of connection parts and compatibility with wood, gas, oil, and pellet appliances. Its 6-inch by 35-foot 316L liner uses 7-ply seams and 10 corrugations, details that help distinguish its construction from the smoother-walled Rockford 35-foot tee kit with insulation, which prioritizes airflow and includes blanket insulation. Here, the appeal is the supplied 13-by-13-inch top plate with integrated rain cap, tee, tee cap, connector, and fasteners, reducing guesswork over basic system components. The tradeoff is that no insulation is specified, and the listed 100-pound item weight calls for planning around handling and delivery. Installation instructions are not specified in the supplied details, so buyers wanting more setup guidance may prefer a kit that explicitly includes it.
Pros:- 316L stainless steel construction with 7-ply seams
- Specified for wood, gas, oil, and pellet appliances
- Includes tee, tee cap, connector, fasteners, and integrated rain cap
- Matches the 6-inch by 35-foot size
Cons:- Blanket insulation is not specified as included
- Listed item weight is 100 pounds, which may complicate handling
- Installation instructions are not specified in the product details
Best for: Homeowners choosing a 35-foot liner for a wood, gas, oil, or pellet appliance who want a tee and rain-capped top plate listed in the package.
Not ideal for: Buyers who require included blanket insulation, lighter handling, or product details that specify installation instructions.
- Material:316L stainless steel
- Liner size:6 inches x 35 feet
- Liner thickness:0.006 inches
- Seams:7-ply
- Corrugations:10
- Included components:13 x 13-inch top plate with integrated rain cap, tee, tee cap, tee connector, fasteners
- Compatible appliances:Wood, gas, oil, and pellet
- Item weight:100 pounds
- Country of manufacture:USA
Our verdict“Pick this kit when its listed tee and termination components matter more than included insulation or smooth-wall construction.”
Fireside Chimney Supply FireSafe Smooth Wall Chimney Liner Kit, 6 Inch x 25 Feet
The FireSafe Smooth Wall is the outlier here: its 6-inch liner is 25 feet long, not 35, so it suits a shorter chimney run rather than buyers who need the roundup’s stated length. Its smooth-wall design is presented as supporting airflow and helping reduce creosote buildup, while the 0.011-inch 316 stainless steel liner comes with a top plate, rain cap, and appliance connector. That makes the package more clearly defined than the Rockford 35-foot insulated kit’s listed component details, but it does not provide the extra ten feet or blanket insulation. Compatibility with wood, gas, oil, and pellet appliances broadens its use, though sizing and setup still need careful attention. I’d shortlist it only when the run measures within its length and smooth-wall construction matters more than matching a 35-foot requirement.
Pros:- Smooth-wall construction supports airflow
- 316 stainless steel liner is 0.011 inches thick
- Includes top plate with rain cap and appliance connector
- Specified for wood, gas, oil, and pellet appliances
Cons:- At 25 feet, it does not meet a 35-foot liner requirement
- Blanket insulation is not listed as included
- Careful sizing and setup are required
Best for: Buyers with a shorter chimney run who want a smooth-wall 316 stainless liner and a listed top plate, rain cap, and appliance connector.
Not ideal for: Anyone specifically needing a 35-foot liner or an included insulation blanket.
- Material:316 stainless steel
- Liner dimensions:6 inches x 25 feet
- Liner thickness:0.011 inches
- Construction:Smooth wall
- Top plate:13 x 13 inches
- Included components:Top plate with rain cap, stainless steel liner, appliance connector
- Compatible appliances:Wood, gas, oil, and pellet
- Item weight:24 pounds
- Country of manufacture:USA
Our verdict“Choose FireSafe for a shorter smooth-wall run, but skip it if 35 feet is a firm length requirement.”
Rockford Chimney Supply 316 Stainless Steel Flexible Chimney Liner Insert Kit, 6 Inch x 25 Feet
This Rockford insert kit is the shorter-run counterpart to the brand’s 35-foot insulated options. Its 6-inch, 25-foot flexible liner comes with a vertical appliance connector, a 13-by-13-inch top plate with quick-connect collar, and a flue cap with mesh screen, giving DIY-oriented buyers a defined set of core parts. The Quick Connect design is intended to simplify assembly, and the product is listed to UL1777 in the USA and ULCS635 in Canada. Unlike the FireSafe Smooth Wall, this is a flexible insert kit rather than a smooth-wall liner, and it does not list insulation as included. The transferable lifetime warranty is a useful ownership feature, but the liner cannot be returned once uncoiled. Measure the flue and offsets carefully before ordering; this is a better match for a verified shorter run than for anyone needing 35 feet.
Pros:- 316 stainless steel flexible liner
- Quick Connect design is intended to simplify installation
- Includes vertical connector, top plate with collar, and screened flue cap
- UL1777-listed in the USA and ULCS635-listed in Canada, with a transferable lifetime warranty
Cons:- The 25-foot length is shorter than the roundup’s 35-foot target
- No insulation is specified as included
- Non-returnable once the liner is uncoiled, so measurements must be accurate
Best for: DIY homeowners with a measured run of 25 feet or less who want a flexible kit with a quick-connect collar and specified cap components.
Not ideal for: Buyers who need 35 feet, want smooth-wall construction, or need the option to return a liner after uncoiling.
- Material:316 stainless steel
- Diameter:6 inches
- Length:25 feet
- Certification:UL1777 (USA), ULCS635 (Canada)
- Construction:7 seams, 10 corrugations per seam
- Included components:Flexible liner, vertical appliance connector, top plate, Quick Connect collar, flue cap
- Warranty:Lifetime, transferable
Our verdict“Choose this for a shorter, carefully measured DIY insert job when its quick-connect parts and warranty matter more than 35-foot length.”
Rockford Chimney Supply Stainless Steel Smooth Wall Chimney Liner Tee Kit, 6 Inch x 35 Feet with Blanket Insulation
For a buyer set on 6 inches by 35 feet, this Rockford kit combines three hard-to-match priorities: smooth-wall construction, a tee connection, and included blanket insulation. The 0.013-inch 316 stainless liner is presented as reducing drag to support airflow and BTU capacity compared with traditional corrugated liners; the blanket adds insulation but also increases the outside diameter by 1.5 inches, making flue clearance a central fit check. Compared with the Chim Cap Forever Vent, this kit emphasizes smooth-wall performance and insulation rather than a corrugated 7-ply liner package. It also lists UL1777 and ULCS635 certifications, a lifetime warranty, and installation instructions. The tradeoffs are bulk and commitment: confirm offsets and narrowing sections before ordering, since the liner cannot be returned after it is uncoiled.
Pros:- Smooth-wall 316 stainless design is intended to reduce airflow drag
- Includes blanket insulation, tee connector, top plate, and quick-connect flue cap
- UL1777-listed in the USA and ULCS635-listed in Canada
- Lifetime warranty and installation instructions are included
Cons:- Insulation adds 1.5 inches to the overall diameter and requires clearance checks
- Non-returnable once the flexible liner is uncoiled
- Offsets and narrowing sections need careful measurement before purchase
Best for: Homeowners with a verified 35-foot masonry flue who want smooth-wall airflow, a tee, and blanket insulation in one kit.
Not ideal for: Buyers with tight flue clearance, uncertain measurements, or a preference for a returnable liner once uncoiled.
- Material:316 stainless steel
- Liner diameter:6 inches inside diameter
- Liner length:35 feet
- Liner thickness:0.013 inches
- Insulation:AES Alkaline Earth Silicate blanket
- Certification:UL1777 (USA), ULCS635 (Canada)
- Warranty:Lifetime
- Model number:SW635S-T-INSKIT
Our verdict“Pick this premium kit when a measured 35-foot run has enough clearance for insulated smooth-wall liner and you want the tee components included.”
Smooth Wall Chimney Liner Kit, 316L Stainless Steel, 6 in x 35 ft
This kit earns its place for buyers who need a 35-foot, 6-inch liner that is specified for wood, gas, oil, and pellet appliances. Its double-ply 316L stainless steel construction and smooth-wall design are intended to support draft while resisting corrosion. The included tee, tee cap, connector, top plate with integrated rain cap, and fasteners make it a more complete package than a bare liner. Compared with the Rockford Chimney Supply 316 Stainless Steel Smooth Wall Chimney Liner Tee Kit, 6 in x 35 ft, this listing specifies compatibility across several fuel types but provides less detail about certifications and installation instructions. Its lifetime warranty is a plus, though the .012-inch thickness is thinner than that Rockford model’s .013-inch liner. The exact diameter and length also need to match the chimney and appliance setup.
Pros:- 316L stainless steel is specified for corrosion resistance.
- Smooth-wall, double-ply construction is designed to support airflow.
- Includes a tee, tee cap, connector, top plate with rain cap, and fasteners.
- Listed as compatible with wood, gas, oil, and pellet appliances.
Cons:- The .012-inch thickness is less than the .013-inch specification of the Rockford smooth-wall tee kit.
- Product data does not provide independent performance details or certification listings.
- The fixed 6-inch diameter and 35-foot length may not suit every chimney.
Best for: Homeowners replacing a 35-foot liner who want a kit specified for wood, gas, oil, or pellet appliances and need the tee and rain-cap top plate included.
Not ideal for: Buyers who need documented UL listings or a thicker liner specification, or anyone whose chimney dimensions do not accommodate a 6-inch by 35-foot run.
- Material:316L stainless steel
- Diameter:6 in
- Length:35 ft
- Thickness:.012 in
- Construction:Double-ply, smooth-wall, multiple corrugations
- Included components:13 in x 13 in top plate with integrated rain cap, tee, tee cap, tee connector, fasteners
- Compatible appliances:Wood, gas, oil, and pellet
- Warranty:Lifetime
Our verdict“Choose this kit when broad fuel compatibility and a full set of basic fittings matter more than a thicker liner specification or listed certifications.”
Rockford Chimney Supply Smooth-Wall Chimney Liner Insert Kit with Insulation, 6 in. x 35 ft.
For a masonry chimney where insulation is part of the installation plan, this kit pairs a smooth-wall 35-foot liner with a 1/2-inch AES blanket. The insulation increases the assembly’s diameter by 1.5 inches, a practical detail that can decide whether it fits an existing flue. The liner is 7-ply with two inner linings, and the kit carries UL1777 and ULCS635 listings; those details give buyers more documented construction information than the Smooth Wall Chimney Liner Kit, 316L Stainless Steel, 6 in x 35 ft. The package also includes a top plate, flue cap, and vertical appliance connector. The tradeoff is fit and commitment: it is for masonry chimneys, and the insulated assembly needs clearance. The listing also says an uncoiled liner cannot be returned, so measuring first matters.
Pros:- Includes a 1/2-inch AES insulation blanket with a foil face.
- UL1777-listed in the United States and ULCS635-listed in Canada.
- 7-ply liner construction with two inner linings.
- Includes a top plate, flue cap, and vertical appliance connector.
Cons:- Specified for installation inside a masonry chimney.
- Insulation adds 1.5 inches to the liner assembly diameter, requiring clearance checks.
- Uncoiled liner cannot be returned.
Best for: Masonry-chimney owners seeking a listed 35-foot smooth-wall liner kit with insulation materials and who can confirm clearance for the enlarged assembly.
Not ideal for: Owners of non-masonry chimney systems or buyers who cannot verify that their flue has room for insulation that adds 1.5 inches to the assembly diameter.
- Liner material:316 stainless steel
- Liner diameter:6 in inside diameter
- Liner length:35 ft
- Liner thickness:0.013 in
- Construction:7-ply with 2 inner linings
- Insulation:1/2 in x 24 in AES blanket with 3 mil foil face
- Added diameter:1.5 in
- Certifications:UL1777 (USA); ULCS635 (Canada)
- Warranty:Lifetime
Our verdict“Pick this insulated, listed kit for a compatible masonry flue when you can confirm clearance before uncoiling the liner.”
Rockford Chimney Supply Stainless Steel Flexible Chimney Liner Tee Kit, 6 in x 35 ft, with Insulation Blanket
This listing suits buyers who want a 35-foot, 6-inch flexible liner bundled with both a tee kit and insulation blanket materials. Its 316 stainless steel construction and UL1777 and ULCS635 listings give it a documented safety profile for the specified application, while insulation is intended to help draft and limit creosote buildup. Compared with the Rockford Chimney Supply Smooth-Wall Chimney Liner Insert Kit with Insulation, this product is framed around a tee-kit configuration rather than a broader insert-kit component list; the supplied data does not spell out the blanket dimensions or liner thickness. That makes exact package verification more important if those specifications affect your installation. It is designed for a masonry chimney, and installation remains a DIY project, so buyers should be comfortable coordinating the liner, insulation, and fittings or plan for professional help.
Pros:- 316 stainless steel liner is specified.
- Includes a tee kit and insulation blanket kit.
- UL1777-listed in the United States and ULCS635-listed in Canada.
- Insulation is intended to support draft and reduce creosote buildup.
Cons:- Designed only for installation inside a masonry chimney.
- Product data does not specify liner thickness or insulation dimensions.
- Installation is a DIY project, so buyers may need to arrange qualified help.
Best for: Masonry-chimney owners who want a flexible 35-foot liner with a tee kit and insulation materials, and who can confirm the included parts suit their layout.
Not ideal for: Buyers needing a clearly specified insulation thickness, liner-wall thickness, or installation service, or those lining a non-masonry chimney.
- Material:316 stainless steel
- Liner diameter:6 in
- Liner length:35 ft
- Included:Tee kit and insulation blanket kit
- Listings:UL1777 (USA); ULCS635 (Canada)
- Installation:Inside a masonry chimney
- Model number:635S-T-INSKIT
- Package dimensions:40 x 29 x 29 in
Our verdict“Choose this when you want an insulated 35-foot tee-kit package for a masonry chimney and can verify the unspecified blanket and fitting details.”
Fireside Chimney Supply FireSafe Stainless Steel Chimney Liner Kit, 6 in. x 25 ft.
The defining choice here is length: this is a 25-foot liner, not a 35-foot kit. That makes it a better match for a measured shorter run than the full-length options in this roundup, including the Smooth Wall Chimney Liner Kit, 316L Stainless Steel, 6 in x 35 ft. It uses 316 stainless steel and includes a 13-by-13-inch top plate with rain cap plus an appliance connector, with compatibility listed for wood, gas, oil, and pellet appliances. The 7-ply seams and 10 corrugations are specified, but its .006-inch thickness is thinner than the 35-foot Rockford smooth-wall tee kit’s .013-inch figure. The package also does not include a tee in the supplied component list. This is a length-specific alternative, not a substitute for buyers who need a 35-foot liner.
Pros:- 25-foot length can suit a shorter chimney run without selecting a 35-foot liner.
- Includes a top plate with rain cap and appliance connector.
- Compatible appliances include wood, gas, oil, and pellet.
- 316 stainless steel is specified for moisture and corrosion resistance.
Cons:- At 25 feet, it does not meet a 35-foot liner requirement.
- The stated .006-inch thickness is below the .013-inch specification of the Rockford smooth-wall tee kit.
- A tee is not listed among the included components.
Best for: Homeowners whose measured chimney run calls for a 25-foot, 6-inch liner and who want a top plate, rain cap, and appliance connector in the kit.
Not ideal for: Buyers who specifically need 35 feet of liner, a tee fitting, or a thicker stated liner construction.
- Material:316 stainless steel
- Diameter:6 in
- Length:25 ft
- Thickness:.006 in
- Seams:7-ply
- Corrugations:10
- Top plate:13 x 13 in
- Included components:Top plate with rain cap, liner, appliance connector
- Compatible appliances:Wood, gas, oil, and pellet
Our verdict“Select this only when a 25-foot run fits your measured chimney; buyers needing the roundup’s 35-foot length should choose a longer kit.”
Rockford Chimney Supply 316 Stainless Steel Smooth Wall Chimney Liner Tee Kit, 6 in x 35 ft
This Rockford kit is the strongest fit for buyers who want a 35-foot smooth-wall liner and a clearly itemized tee assembly. The 7-ply 316 stainless liner has two inner linings and a stated .013-inch thickness, while the package includes a quick-connect top plate, screened flue cap, tee connector with removable snout, and cleanout cap. That component detail makes it easier to compare against the Smooth Wall Chimney Liner Kit, 316L Stainless Steel, 6 in x 35 ft, whose data lists several fittings but gives less construction and certification detail. This model is UL1777- and ULCS635-listed and includes installation instructions plus a transferable lifetime warranty. The tradeoffs are a masonry-chimney-only application and the need to allow clearance beyond the 6-inch inside diameter. Its uncoiled liner cannot be returned, so confirm fit before opening it.
Pros:- 7-ply 316 stainless liner with two inner linings and a stated .013-inch thickness.
- Includes tee connector with removable snout, cleanout cap, top plate, and screened flue cap.
- UL1777-listed in the United States and ULCS635-listed in Canada.
- Transferable lifetime warranty and installation instructions are included.
Cons:- Specified for installation inside a masonry chimney.
- Requires clearance beyond the stated 6-inch inside diameter.
- Uncoiled liner cannot be returned.
Best for: Masonry-chimney owners who want a 35-foot smooth-wall liner with a specified tee, removable snout, cleanout cap, listed certifications, and installation instructions.
Not ideal for: Buyers without a masonry chimney, anyone unable to confirm clearance around the liner, or those who need a return option after uncoiling.
- Material:316 stainless steel
- Liner diameter:6 in inside diameter
- Liner length:35 ft
- Liner thickness:0.013 in
- Construction:7-ply with 2 inner linings
- Top plate:13 x 13 in with quick-connect collar
- Tee snout:10 in, trimmable
- Certifications:UL1777 (USA); ULCS635 (Canada)
- Warranty:Transferable lifetime
Our verdict“Choose this well-specified tee kit for a compatible masonry chimney when you want detailed fittings and certification information and can verify fit before uncoiling.”
Rockford Chimney Supply 316 Stainless Steel Flexible Chimney Liner Tee Kit, 6 in x 35 ft
This is the most purpose-built choice here for a setup that needs a tee connection: the kit pairs a 6-inch, 35-foot 316 stainless liner with a tee, cleanout cap, top plate, and mesh-screen flue cap. Its removable, trimable 10-inch snout gives an installer room to adapt the connection, while the cleanout cap supports access for maintenance. Compared with the standard Rockford 35-foot liner kit, this one adds the tee assembly rather than leaving that connection to be sourced separately. It also includes UL1777 and ULCS635 listings and a transferable lifetime warranty. The tradeoff is fit: it is intended for a masonry chimney, and the flue should be checked for obstructions and dimensions before ordering. Because the liner cannot be returned once uncoiled, measuring first matters.
Pros:- Includes liner, tee connector, cleanout cap, top plate, and mesh-screen flue cap
- 316 stainless steel liner is described as air- and water-tight
- Removable, trimable 10-inch tee snout allows adjustment at the connection
- UL1777 and ULCS635 listings plus a transferable lifetime warranty
Cons:- Designed for installation inside a masonry chimney
- Flue fit and obstructions need to be checked before purchase
- Uncoiled liner cannot be returned
Best for: Homeowners with a masonry chimney who need a 35-foot liner kit that includes a tee connection and cleanout access.
Not ideal for: Buyers lining a non-masonry chimney, or anyone unable to verify flue dimensions and clearance before uncoiling the liner.
- Material:316 stainless steel
- Liner diameter:6 inches inside diameter
- Liner length:35 feet
- Tee snout:10 inches; removable and trimable
- Top plate:13 x 13 inches
- Listings:UL1777 (USA); ULCS635 (Canada)
- Warranty:Transferable lifetime warranty
- Model:635S-T
Our verdict“Choose this kit when your masonry-chimney installation needs an included tee and cleanout, and skip it if the flue fit is uncertain.”
Rockford Chimney Supply 316 Stainless Steel Flexible Chimney Liner Kit, 6 in. x 35 ft.
For buyers who need the specified 6-inch by 35-foot length but do not need a tee or smooth-wall construction, this is the least specialized of the three Rockford options. Its 316 stainless steel liner, quick-connect system, and installation instructions keep the package focused on the core liner installation. Unlike the tee kit in this lineup, it does not list a tee connector, snout, or cleanout cap, so it suits a setup where those parts are unnecessary or already accounted for. The Smooth Wall Chimney Liner Insert Kit offers a smooth interior and named top-plate and appliance-connector components, while this model keeps to a simpler flexible-liner format. It carries UL1777 and ULCS635 listings and a transferable warranty, but the supplied description does not specify the warranty term. It is for masonry chimneys only.
Pros:- 316 stainless steel construction in the requested 6-inch diameter and 35-foot length
- Quick Connect System is included
- UL1777 (U.S.) and ULCS635 (Canada) listed
- Installation instructions and a transferable warranty are included
Cons:- Designed for installation inside a masonry chimney only
- The listed kit contents do not include the tee and cleanout supplied with the Rockford tee kit
- Product data does not specify the transferable warranty term
Best for: Masonry-chimney owners who need a 35-foot, 6-inch flexible liner and already have a plan for the appliance connection and other fittings.
Not ideal for: Buyers who need a complete tee-and-cleanout package, a smooth-wall interior, or a liner for a non-masonry chimney.
- Material:316 stainless steel
- Diameter:6 inches
- Length:35 feet
- Installation:Inside a masonry chimney
- Connection:Quick Connect System
- Certifications:UL1777 (U.S.); ULCS635 (Canada)
- Manufacturer:Rockford Chimney Supply
- Model:635S-AC
Our verdict“Pick this model for a straightforward masonry-chimney liner run when you do not need the tee kit’s extra connection hardware.”
Rockford Chimney Supply 316 Stainless Steel Smooth Wall Chimney Liner Insert Kit, 6 in x 35 ft
This kit is the distinct choice for buyers prioritizing a smooth interior in a 6-inch, 35-foot liner. The product description says the smooth surface is designed to improve airflow, making that construction the main reason to choose it over the standard Rockford flexible liner kit. It also specifies 7-ply 316 stainless steel at 0.013-inch thickness and includes a top plate with quick-connect collar, mesh-screen flue cap, and vertical appliance connector. Compared with the tee kit, it supplies a vertical connector rather than a tee and removable snout, so the right pick depends on the appliance connection your installation needs. UL1777 and ULCS635 listings and a transferable lifetime warranty add documented support. The tradeoffs are its masonry-chimney-only use and the need to confirm fit before handling: the liner cannot be returned once uncoiled.
Pros:- Smooth interior is designed to improve airflow
- 7-ply 316 stainless steel liner with specified 0.013-inch thickness
- Includes top plate, mesh-screen flue cap, and vertical appliance connector
- UL1777 and ULCS635 listings with a transferable lifetime warranty
Cons:- Designed for installation inside a masonry chimney
- Does not list the tee connector and cleanout included with the Rockford tee kit
- Uncoiled liner cannot be returned
Best for: Masonry-chimney owners who want a 35-foot smooth-wall liner and need the included vertical appliance connector rather than a tee.
Not ideal for: Buyers who need a tee-and-cleanout setup, are lining a non-masonry chimney, or cannot verify the flue fit before uncoiling.
- Material:316 stainless steel
- Liner construction:7-ply smooth-wall flexible liner
- Liner thickness:0.013 inches
- Inside diameter:6 inches
- Liner length:35 feet
- Included components:Top plate with quick-connect collar, flue cap with mesh screen, vertical appliance connector
- Listings:UL1777 (USA); ULCS635 (Canada)
- Warranty:Transferable lifetime warranty
- Installation:Inside a masonry chimney
Our verdict“Choose this insert kit for a smooth-wall 35-foot run with a vertical appliance connection, not for a setup that needs a tee.”
How We Picked
I organized this roundup around the details that most affect whether a liner kit fits a real installation: 6-inch diameter, listed length, liner construction, kit configuration, and insulation inclusion. I gave the closest matches to the 6-inch, 35-foot search more weight, then distinguished flexible from smooth-wall options and standard, insert, and tee kits. These labels describe different configurations, not interchangeable upgrades, so a higher position reflects a stronger match for the stated search—not a claim that one style suits every chimney.
I also considered how clearly each listing signals its intended use and what a buyer still needs to verify. A 25-foot kit may fit a shorter measured run better than a 35-foot option, while a tee kit may be the relevant choice for a side connection. Insulation can add to the package but also affects installation planning. I ranked the options to make those tradeoffs visible and avoid treating length, wall style, or included parts as minor details.
| inch stainless chimney liner kit 35 ft | Warranty |
|---|---|
| Rockford Chimney Supply 316 St | — |
| Chim Cap Forever Vent Flexible | — |
| Fireside Chimney Supply FireSa | — |
| Rockford Chimney Supply 316 St | Lifetime, transferable |
| Rockford Chimney Supply Stainl | Lifetime |
| Smooth Wall Chimney Liner Kit | Lifetime |
| Rockford Chimney Supply Smooth | Lifetime |
| Rockford Chimney Supply Stainl | — |
| Fireside Chimney Supply FireSa | — |
| Rockford Chimney Supply 316 St | Transferable lifetime |
| Rockford Chimney Supply 316 St | Transferable lifetime warranty |
| Rockford Chimney Supply 316 St | — |
| Rockford Chimney Supply 316 St | Transferable lifetime warranty |
Factors to Consider When Choosing 6 Inch Stainless Chimney Liner Kit 35 Ft
Before selecting a kit, match the product configuration to the appliance, chimney route, and installation plan. The listing title alone cannot confirm compatibility: measurements, connection parts, and applicable installation requirements all matter. These checks can help prevent choosing a liner that is the right diameter but the wrong length or configuration.
Measure the Run Before Choosing 25 or 35 Feet
Do not assume that a 35-foot liner is automatically the safer choice because it gives extra length. Measure the route from the appliance connection to the top of the chimney, accounting for the path and the installation method specified for the system. A 25-foot option may be a better match for a shorter run, while an undersized liner can leave you without enough material. Check how the seller describes usable liner length and whether the kit includes components that affect the installed height. Choose by measured run, not by the search phrase alone. If your measurements are close to a kit’s limit, ask the manufacturer or installer before ordering.
Match the Liner Style to the Chimney Route
Flexible liners are generally the more adaptable listing category when a route has bends or an irregular path, while smooth-wall versions appeal to buyers who want that specific interior design. The product names in this roundup do not provide enough information to confirm the minimum bend radius or every installation constraint, so verify those details for your chimney. A smoother wall should not be treated as a universal performance guarantee or as a reason to ignore fit. Compare the liner’s construction with the actual route and appliance requirements. Route compatibility comes before a preferred finish. If the path is complex, get the configuration confirmed before purchasing.
Check Whether You Need a Tee or an Insert Kit
A tee kit and an insert kit indicate different installation configurations, so do not select between them based only on the liner’s length or material. A tee may be relevant when the appliance connection meets the liner from the side, while an insert kit may suit a setup designed around inserting a liner into an existing chimney. Confirm the connection point, included components, and how they relate to your appliance before checkout. Product titles do not spell out every part or installation scenario. Verify the parts list against your connection plan rather than assuming all kits include the same fittings. When the setup is unclear, have a qualified installer identify the needed configuration.
Treat Insulation as an Installation Decision
Some Rockford listings explicitly include a blanket insulation, while other options in the roundup do not say so in their titles. That difference can affect what you need to source and how the installation is planned, but a title is not a substitute for a complete parts list. Check whether insulation is included, what the package contains, and whether the chimney and appliance installation calls for it. Do not assume that adding insulation is appropriate in every situation or that every kit can use the same insulation method. Confirm the required insulation approach before buying. This step helps avoid ordering a liner package that does not match the approved installation plan.
Compare Stainless Grades and Verify Application Compatibility
The listings name 316 or 316L stainless steel for several products, but material grade alone does not confirm that a liner is suitable for your appliance or fuel. Check the manufacturer’s stated applications, product documentation, and applicable local requirements. Also confirm that the liner diameter is appropriate for the appliance rather than relying on the existing chimney opening as a guide. A 6-inch liner is only the right choice when the appliance specifications and installation design support that size. Compatibility depends on the whole system, including appliance, connector, liner, and chimney conditions. Ask a qualified professional when those specifications do not align clearly.
Compare the Full Kit Contents, Not Just the Headline
Two products described as 6-inch, 35-foot kits may differ in liner style, tee or insert configuration, insulation, and supplied hardware. Read the detailed parts list to see what is included and identify components you may need separately. Check whether the kit is intended for your installation type and whether the listed fittings match your appliance connection. A lower-complexity package may be the better fit if it matches a straightforward installation, while a more complete configuration can reduce sourcing work when its parts are actually needed. Judge value by fit and included components, not by length or stainless grade alone. Confirm any uncertain details with the seller or installer before committing.
Frequently Asked Questions
Is a 35-foot liner always a better choice than a 25-foot liner?
No. The correct length depends on the measured chimney route and the kit’s installation requirements, not on which listing is longer. This roundup includes both 35-foot options and 25-foot Fireside and Rockford kits, so buyers should measure before choosing. A shorter kit may suit a shorter run, while a 25-foot liner may not reach a taller or more complex route. Confirm the usable length and installation details with the manufacturer or installer if your measurement is close to the limit.
How do I decide between flexible and smooth-wall liner kits?
Start with the chimney’s route and the appliance installation requirements rather than treating either style as universally superior. Flexible kits may be worth comparing for a route that needs adaptability, while smooth-wall kits are the choice when that construction is specified or preferred for the installation. The product titles alone do not establish which design fits a particular bend or chimney. Check the manufacturer’s guidance for routing limits and confirm the configuration with your installer. Fit the liner style to the route before weighing other differences.
Do I need a tee kit, or is a standard liner kit enough?
That depends on how the liner connects to your appliance and the existing chimney setup. The tee listings in this roundup identify a distinct configuration, but the title does not tell you whether its included parts match your connection. Compare the kit’s parts list with the planned connection point and ask an installer to identify any required fittings. A standard kit may be a better match for another installation arrangement. Do not infer the connection type from the 6-inch diameter alone.
Should I choose a kit that includes blanket insulation?
Choose insulation based on the requirements of your appliance, chimney, and installation plan rather than assuming every liner needs the same package. Several Rockford listings explicitly include a blanket, which can make them relevant when an insulated configuration is called for. Other titles do not identify insulation, so review the full package contents before buying. Confirm that the insulation method is approved for the specific system and installation. Check the required approach and included materials with the product documentation or a qualified installer.
What should I verify before ordering a 6-inch kit for my appliance?
Confirm that 6 inches matches the appliance’s specified flue size and that the selected liner is approved for its fuel and application. Then check the chimney length, route, kit style, connection configuration, and included components. The roundup includes different lengths and tee, insert, flexible, and smooth-wall options, so the same diameter does not make every kit interchangeable. Review manufacturer documentation and local installation requirements before purchase. Ask a qualified professional to resolve any mismatch between the appliance specification and the planned liner.
Conclusion
For most shoppers specifically seeking a 6-inch, 35-foot kit, I would start with the Rockford 316 flexible kit with blanket insulation as the best overall match. The best value is the option whose length and included configuration fit the job without requiring unneeded parts; compare the Rockford and Chim Cap flexible listings by package contents rather than headline alone. For a premium smooth-wall preference, consider the 35-foot Rockford smooth-wall choices, checking whether insulation and the needed connection parts are included. For beginners, the best first step is to confirm measurements and have an installer identify whether a standard, insert, or tee kit is called for before selecting a product. For a shorter run, compare the 25-foot Fireside or Rockford options; for a side connection or insulated setup, focus on the matching tee or blanket-insulated configuration. The right choice is the kit that matches your measured route, appliance, and installation plan—not simply the one with the longest title.
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