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Premium Quality 100mm (4 Inch) Flue Liner and Accessories - National Flues UK

Welcome to our 100mm (4 Inch) category where we stock an extensive range of flue liners and accessories crafted to fit most heating appliances. The 100mm (4 Inch) MI-Flex 904L is one of our top products, with its strong, durable design, compliance with British Standards, and being CE approved. Ideal for both domestic and commercial use, these flues meet the highest safety standards. With a sturdy, easy-to-fit design these can be the perfect for compatibility with solid fuel, wood, gas, and oil appliances.
Welcome to our 100mm (4 Inch) category where we stock an extensive range of flue liners and accessories crafted to fit most heating appliances. The 100mm (4 Inch) MI-Flex 904L is one of our top products, with its strong, durable design, compliance with British Standards, and being CE approved. Ideal for both domestic and commercial use, these flues meet the highest safety standards. With a sturdy, easy-to-fit design these can be the perfect for compatibility with solid fuel, wood, gas, and oil appliances.


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The best selling flue liner in the UK. Suitable for gas, oil, and approved solid fuels. Call our advisers on 01670 206 999 if you need any help choosing.

£1.93 £2,537.99
Showing 20 of 30 items
904L Mi-FLEX 100mm x 1m CUT LENGTH

904L Mi-FLEX 100mm x 1m CUT LENGTH

36Z-100-1
£44.99 (including VAT)
In stock
904L Mi-FLEX 100mm x 44m COIL

904L Mi-FLEX 100mm x 44m COIL

36Z-100-44
from £2,537.99 (including VAT)
In stock
Jubilee Clip and Banding Ø 200 - 800mm length

Jubilee Clip and Banding Ø 200 - 800mm length

13-JUBILEE-200
£3.99 (including VAT)
In stock
Jubilee Clip and Banding Ø 300 - 1000mm length

Jubilee Clip and Banding Ø 300 - 1000mm length

13-JUBILEE-300
£4.99 (including VAT)
In stock
Bolted MI-FLEX Adaptor - Ø 100

Bolted MI-FLEX Adaptor - Ø 100

20-100-BL-MAE
£23.99 (including VAT)
In stock
Top clamp - Ø 100

Top clamp - Ø 100

20-100-C
£9.99 (including VAT)
In stock
Joiner - Ø 100

Joiner - Ø 100

20-100-J
£23.99 (including VAT)
In stock
MI-FLEX Adaptor - Ø 100

MI-FLEX Adaptor - Ø 100

20-100-MA
£20.99 (including VAT)
In stock
Increasing MI-FLEX Adaptor - Ø 100-Ø 125

Increasing MI-FLEX Adaptor - Ø 100-Ø 125

20-100-MR
£20.99 (including VAT)
In stock
Nose Cone - Ø 100

Nose Cone - Ø 100

20-100-NC
£5.99 (including VAT)
In stock
Top Plate - Ø 100

Top Plate - Ø 100

20-100-P
£11.99 (including VAT)
In stock
Rain Cap - Ø 100

Rain Cap - Ø 100

20-100-RC
£20.99 (including VAT)
In stock
Chimney Notice Plate

Chimney Notice Plate

20-CNP
£1.93 (including VAT)
In stock
Chimney Notice Plate - 50 Pack

Chimney Notice Plate - 50 Pack

20-CNP48
£90.99 (including VAT)
In stock
Screw-FIX Flex Joiner - Ø 100

Screw-FIX Flex Joiner - Ø 100

25-100-J
£34.99 (including VAT)
In stock
Screw-FIX Adaptor to SW - Ø 100

Screw-FIX Adaptor to SW - Ø 100

25-100-MAE
£13.99 (including VAT)
In stock
Screw-FIX Long Tail Adaptor - Ø 100

Screw-FIX Long Tail Adaptor - Ø 100

25-100-MAELT
£25.99 (including VAT)
In stock
Screw-FIX Increaser - Ø 100-125mm

Screw-FIX Increaser - Ø 100-125mm

25-100-MR
£24.99 (including VAT)
In stock
Screw-FIX Pot Hanging Cowl, Natural - Ø 100

Screw-FIX Pot Hanging Cowl, Natural - Ø 100

25-100-PHCM
£43.99 (including VAT)
In stock
Screw-FIX Rain Cap - Ø 100

Screw-FIX Rain Cap - Ø 100

25-100-RC
£24.99 (including VAT)
In stock
Your 100MM (4 INCH) Questions Answered

Why choose 904L stainless steel for flue liners? -

904L grade stainless steel provides excellent corrosion resistance and long-term reliability. It's designed to withstand extreme temperatures and conditions, makken it a superb choice for flue liners.

What's the difference between bottom fixings and top fixings? +

Can I fit these flues meself? +

What sort of requisite should be used with the 100mm flue liners? +

How long does a 904L Mi-FLEX flue liner last? +

Which flue liner product should I choose, the 1m cut length or the 44m coil? +

Are the 100mm accessories equally applicable to all types of flue environments? +

In the world of fireplace flues, the 10MM (4 INCH) category stands out for its versatility and compatibility. With products like MI-Flex and fixings designed specifically for this size, homeowners can achieve seamless installations that meet safety regulations. Understanding the importance of top and bottom fixings is key to ensuring a secure chimney structure. Moreover, the Increasing MI-FLEX Adaptor simplifies the process of transitioning from an 80MM (3 INCH) flue to a 100MM one, offering flexibility and convenience for installers.
Why Buy 100MM (4 INCH) Products
100MM (4 INCH) fireplace flues are commonly utilized in residential settings where space may be limited. Due to their compact size, these flues are ideal for small to medium-sized fireplaces and wood-burning stoves. The MI-Flex range and fixings cater specifically to this category, providing homeowners and installers with the necessary components for a successful chimney installation. Whether you're upgrading an existing system or building a new fireplace, 100MM (4 INCH) flues offer reliability and performance.

Trusted By Trade Professionals

Our 100MM (4 INCH) products and services are trusted by hundreds of professionals nationwide. We're committed to providing quality and reliability that meets the high standards of our customers.

Dedicated Support

Experience our unparalleled customer service and support when you buy 100MM (4 INCH) from National Flues. Our team is here to assist you every step of the way, ensuring your needs are met with expertise and care.