Flue and Chimney Design Service - Internal insulated flue

Flue and Chimney Design Service

An internal twin wall insulated flue system goes straight up from the stove, through any floors and/or ceilings in the house and then through the roof. Where the flue goes through the roof a flashing keeps everything watertight. The roof penetration is usually the part that customers are most concerned about, however it is not a difficult job and it is easy to make a weatherproof seal around the flue and roof using one of our range of flashings. An internal flue system is kept warmer than an external one and therefore keeps the flue gases hotter, resulting in better draw and less tar desposits.

It is cheaper, quicker and easier to install an internal twin wall flue system than an external system. The internal system does not require a hole in the wall nor expensive bends and tee pieces.

For our flue designers to design your internal flue system using insulated twin wall flue pipe we will need a few details and measurements from you. The big link below will take you to our application form where you can enter these details.

It takes a little bit of time to gather the measurements and details that we need and to help out we have made a printable checklist of all the details needed - you simply print this list out and then fill in the spaces as you go.

Click here for the application form

Some decisions you will have to make about your flue system

Single skin flue pipe - you can run the first section of flue from the stove using single skin flue pipe. Most stove manufacturers recommendation is not to use more than one metre of single skin before going into twin wall insulated flue pipe. You have to change from single to double before the flue reaches the ceiling. So, on the one hand, single skin flue is cheaper than double skin, but on the down side it does mean that you have two different types of flue (with different external diameters) within the room.

Type of single skin flue pipe - you can choose black enamel flue or stainless steel flue. The stainless steel flue pipe lasts longer than enamel flue, fits better with double skin adaptors and can be sprayed to match the stove.