DuraFlex Pro ultra flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters.
DuraFlex SW smooth wall flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters.
DuraFlex 316 flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliance. Applications include: fireplace inserts, furnaces, boilers, and water heaters. 316 is designed for use in harsher conditions, for more resistance to corrosion, such as coal.
DuraFlex 304 flexible relining for masonry chimney. Use with gas, wood pellet, oil, or wood appliances. Applications include: fireplace inserts, furnaces, boilers, and water heaters.
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.
DuraFlex Pro: 0" clearance for gas, oil, and pellet applications. 1" clearance to masonry for wood-burning applications. Insulation is required for 0" clearance to masonry for wood-burning.
DuraFlex SW: Clearances 0" clearance for gas, oil, and pellet applications. " clearance to masonry for wood-burning applications. Insulation is required for 0” clearance to masonry for wood-burning.
DuraFlex 316 & 304: 0" clearance for gas, oil, and pellet applications. 1" clearance to masonry for wood-burning applications. Insulation is required for 0" clearance to masonry for wood-burning.
DuraFlex Pro & SW: 3", 12".
DuraFlex 316 & 304: 3", 8".
DuraFlex Pro: Listed to UL 1777 and ULC S635 (MH45609).
DuraFlex SW: Listed to UL 1777 (MH45609).
DuraFlex 316 & 304: Listed to UL 1777 and ULC S635 (MH45609).
Refer to our Typical Venting Installation drawings to select the appropriate component parts for your installation.
- The inner pipe diameter should match the outlet size of the appliance.
- Check the appliance manufacturer’s installation instructions to confirm which types of vent configurations are permitted (i.e. horizontal, vertical, chimney reline, etc.). Also, check for any venting restrictions such as maximum horizontal run, minimum and maximum vertical rise, maximum offset, etc.
- Be fire safe! Use proper support and bracing. Follow local building codes and have your venting system inspected.
More Typical Installations:
|Installation Key |
|1 ||DuraFlex SS Cap |
|2 ||DuraFlex AL Cap |
|3 ||DuraFlex Top Plate |
|4 ||DuraFlex (SW, Pro, 304, 316) Length |
|5 ||DuraFlex AL Length |
|6 ||DuraFlex SS Tee |
|7 ||DuraFlex AL Tee |
|8 ||DuraFlex Mortar Sleeve |
|9 ||DuraFlex AL Coupling |
|10 ||DuraFlex SS Connector |
|11 ||PelletVent Pro Appliance Adapter |
|12 ||DuraBlack Trim Collar |
|13 ||Rigid Type B Gas Vent |
|14 ||Rigid PelletVent (L Vent) |
|15 ||ProFoil Insulation, AluFoil Tape & ProMesh |
|16 ||DVL or DuraBlack Pipe |
|17 ||Pipe Collar (B-Vent) |
Planning Your Installation:
|1 ||Verify the venting requirements of the appliance used. Choose the liner system appropriate for the appliance and installation. |
|2 ||Refer to the Typical Installations for the type of liner installation similar to your situation. Identify the needed parts for installation. |
|3 ||The size of the liner should match the outlet size on the appliance or the size of the vent/manifold that penetrates into the masonry chimney. |
|4 ||Determined the length of the liner needed. |
|5 ||Make sure of a proper fit for the Top Plate of the reliner to provide a secure, leak-proof installation. |
|6 ||If a free-standing appliance is used, select the vent or stovepipe pieces to connect from the appliance to the liner (refer to the appropriate section of catalog). |
|7 ||Important! Check to be sure the installation complies with all local and national code requirements, including clearance to combustibles. Contact the local building inspector for permit requirements. |
- The following design recommendations are intended only as a general guideline to assist in the design and selection of liner components for your installation. Always read and follow DuraVent Installation instructions (enclosed with the cap or support box) before installing DuraFlex. Installation instructions can be viewed online at www.duravent.com, under catalogs and instructions.
- Before relining a chimney, it should be cleaned and inspected to verify the integrity of the mortar and masonry. In addition, have a certified chimney professional determine if the masonry was constructed with 0” or 1” clearance to the surrounding combustibles. This is an important fire safety issue that may have an influence on how the liner is installed.
- Be sure to select the proper liner for the application. DuraFlex SS is used for appliances that use oil, wood, or wood-pellets for fuel; DuraFlex AL is for a non-condensing gas appliance. Refer to the appliance manufacturer for installation requirements affecting venting. Keep the vent path as straight as possible for best performance.
M&G DuraVent Limited Lifetime Warranty
M&G DuraVent, Inc. (“DuraVent”) provides this limited lifetime warranty for all of its products with the exception of Ventinox® (lifetime), and PolyPro® (ten years). Subject to the limitations set forth below, DuraVent warrants that its products will be free from defects in material or manufacturing, if properly installed, maintained and used. DuraVent products are fully warranted if installed only by a professional installer. This Warranty is transferable from the original homeowner to the buyer of the home. This warranty does not cover normal wear and tear, smoke damage or damage caused by chimney fires, acts of God, or any product that was: (1) purchased other than from an authorized DuraVent dealer, retailer or distributor; (2) modified or altered; (3) improperly serviced, inspected or cleaned; or (4) subject to negligence or any use not in accordance with the installation instructions included with the product as determined by DuraVent. Installation instructions are available online at www.duravent.com under Support/Literature and through our Customer Service Department 800-835-4429 or email@example.com. This limited lifetime warranty applies only to parts manufactured by DuraVent.
DuraVent provides the following warranties for its products: One Hundred Percent (100%) MSRP 15 years from the date of purchase, and Fifty Percent (50%) thereafter, except for the following limitations on: all Termination Caps and DuraBlack® are warranted at One Hundred Percent (100%) for five years.
All warranty obligations of DuraVent shall be limited to repair or replacement of the defective product pursuant to the terms and conditions applicable to each product line. These remedies shall constitute DuraVent’s sole obligation and sole remedy under this warranty. This warranty provides no cash surrender value. The terms and conditions of this warranty may not be modified, altered or waived by any action, inaction or representation, whether oral or in writing, except upon the express, written authority of an executive officer of DuraVent.
Corn, bio-fuels, driftwood or other wood containing salt, preservative-treated lumber, plastic and household trash or garbage, or wood pellets containing such materials must not be burned in the appliance or fireplace. In case of a chimney fire, the chimney must be inspected and approved by a certified Chimney Sweep before reuse. After each annual inspection, maintenance, and cleaning, the certified Chimney Sweep must fill out and date the appropriate section of the warranty card provided with the chimney liner.
LIMITATIONS ON INTERNET SALES: Notwithstanding any other terms or conditions of this Limited Lifetime Warranty, DuraVent provides no warranty for the following specific products if such products are not installed by a qualified professional installer: DuraTech®, DuraPlus HTC®, DuraChimney® II, PelletVent Pro®, DirectVent Pro®, FasNSeal®, FasNSeal® W2, FasNSeal® Flex, and PolyPro®, and M&G DuraVent’s relining products including DuraLiner®, DuraFlex® (SW, Pro, 316, 304), and Ventinox®. For purposes of this warranty, a trained professional installer is defined as one of the following: licensed contractors with prior chimney installation experience, CSIA Certified Chimney Sweeps, NFI Certified Specialists, or WETT Certified Professionals.
DuraVent must be notified and given the opportunity to inspect defective product prior to replacement under the terms of this limited lifetime warranty. All warranty claims must be submitted with proof of purchase. Labor and installation costs are not covered under this warranty. To obtain warranty service contact: DuraVent Warranty Service, 877 Cotting Ct., Vacaville CA 95688, or call 800-835-4429.
WHERE LAWFUL, DURAVENT DISCLAIMS ALL OTHER WARRANTIES, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL DURAVENT BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR SPECIAL DAMAGES OR DIRECT OR INDIRECT LOSS OF ANY KIND, INCLUDING BUT NOT LIMITED TO PROPERTY DAMAGE AND PERSONAL INJURY. DURAVENT’S ENTIRE LIABILITY IS LIMITED TO THE PURCHASE PRICE OF THIS PRODUCT. SOME STATES DO NOT ALLOW LIMITATIONS ON IMPLIED WARRANTIES, OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHTS THAT VARY FROM STATE TO STATE.
M&G DuraVent Limited Lifetime Warranty (PDF, 146KB )
M&G DuraVent is the first manufacturer to have a UL-listed relining system for factory-built chimneys to be used with solid-fuel appliances in the USA. When a homeowner installs a wood-burning insert into an existing UL127-listed fireplace, relining the existing chimney is critical for performance and safety. Check installation video on our youtube channel
What does the UL listing cover?
All 127, 103, or 103HT chimneys
Insulated chimneys- all sizes with 2” clearance
Air cooled - clearance based on diameter
All M&G Duravent UL1777 systems up to 8”
Flex does not need insulation!!!
Air Cooled Chimney Coverage:
Up to 8” I.D. chimneys with at least 1 ¼” wall (ex. 8x10½)
6x8½ is OK, 8x11 is OK
Up to 8” I.D. chimneys require at least 1 ½” clearance
Larger chimneys with at least 1 ½” wall (ex. 10x13)
9x12 is OK, 10x14 is OK, 16x19 is OK
Chimneys larger than 8” require at least 2” clearance
Factory-Built Reline Kit includes:
DuraLiner 12” Length
Flex Length (25’ or 35’)