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We love hearing from our customers. Please contact us about anything at all. Your new installation, future project or request for a specific product. We’ll do everything we can to make your experience unforgettable every time. Here are several questions we are asked alot and may assist you in your purchase.

Frequently Asked Questions

What Flue Liner Do I Need?

We offer 3 different grades of flexi flue liner which are ALL capable of burning oil and gas, but differentiate when burning solid materials.

  • Our 316/316 is for wood only burning
  • Our 904/316 is for wood and coal burning
  • Our 904/904 is capable of burning wood, coal and smokeless materials

All our chimney liners come in lengths from 1 to 40 meter coils if required



What Are The Clearing Distances For Stove Pipe / Flexi Liner & Twinwall?

Each type of liner we sell, whether it be stove pipe, flexi liner or twin wall must conform to the minimum requirements set by the manufacturers specific specifications in order for them to be signed off.

For stove pipe, the regulations are that throughout the entirety of the installation, a minimum of 3x the internal diameter must kept from any combustible materials. As an example, if you're using 5" stove pipe, you must have a minimum of 15" from anything that's combustible.

Any of our flexi liners, a minimum of 25mm between the flue liner and the wall of the chimney stack must be maintained for the entire length of the liner. For example, a 10" square stack, a maximum of 8" liner can be used.

For our twin wall liner, a minimum of 60mm (2.5") must be kept from any combustibles throughout the whole installation.


Does It Matter Which Way MyFlexi Liner Dropped Down The Stack?

When you receive your flexi liner, you should notice small arrows situated on the side of it. These arrows must be facing in the upwards position as it indicates to which way the flue gases go.

How Much VermiculiteDo I Need?

The calculation used to determine how much vermiculite is dependent on a few factors. For an average sized UK chimney stack (9x9 inches) if using 6" flexi liner, one bag of vermiculite is equivalent to 2.2 meters of liner. You must adjust the calculation in accordance to the size of the chimney stack that you have to ensure that your liner has the appropriate amount of insulation required.

Do I Receive Locking Bands With All Pieces Of twin Wall?

You will receive locking bands with each part of twin wall except our cowls. If you are installing a full system, the locking band that you receive from the adaptor is surplus, thus can be used to secure the cowl to the twin wall

How Long Is Your Liner Guaranteed For?

All of our flexi liners come with a lifetime guarantee (for as long as you own the property).

Where Do I Send Back Items I Wish To Return?

Any items that you wish to send back (apart from flexi liner or any other bespoke items) must be returned to our suppliers' address which can be found on the returns form that can be found under the orders and returns section of the website. Please note that there may be re-stocking charges to take into consideration if you wish to send items back after certain period of time.

  • Up to 14 calendar days after date of delivery – No restocking charge
  • Between 14-21 calendar days after date of delivery – 15% restocking charge
  • Anything after 21 calendar days after date of delivery – 25% restocking charge

Can I Return Flexi Flue Liner?

We don't accept any returns on flexi liner as it's considered a bespoke item (cut to your specifications)

Can I Reduce The Size Of The Liner If It's Smaller Than The Outlet Size?

We do not sell any adaptors/accessories that decrease the size of any liner as you ascend into your installation, as it constricts the flow of heat, with the likelihood of a fire occurring

Vat no. 173389871- Company No. 08618240 - Registered Name: Chimney Supplies Ltd t/a NCS - Copyright © 2023-present National Chimney Supplies