When should I use double wall flue?

Twin wall flue pipe should be used when you do not have an existing chimney stack to connect your appliance to. It an also be used in situations such as sheds & boats.

Can you cut twin wall pipe?

You should not cut twin wall flue pipe . You should therefore plan your chimney flue carefully and purchase the correct lengths required.

How do you install twin wall flue? 

The flue fits together with a simple push fit system, with a locking band to hold in place. The chimney should be as straight as possible, minimising the amount of bends, with the distance between bends not to exceed 20% of the total vertical height. For complete regulations please refer to Building Regulations Approved Document Part J

How many bends can I have in my twin wall chimney?

You should have no more than 4 bends in your chimney.

What size twin wall flue do I need?

The diameter of flue will depend on what fuel you are using and the rating of the stove.
For example, building regulations dictate the following:

● Up to 20 kW (burning smokeless fuels) Min 125mm diameter.
● Up to 30 kW (burning any fuel) Min 150 mm diameter.
● Defra exempt stoves: 125 mm diameter

It may be possible to use 100mm 4 inch twin wall in certain situations – for example sheds, outbuildings and boats – please call us to check your exact situation.