External twin wall flue 

 An external flue is made from twin wall insulated pipes. The passage through the wall is made with a 45º T piece.

A typical installation is drawn below.

The connection to the appliance is made with single wall vitreous parts. 

As standard, twin wall flue will, to comply with Building Regulations, protrude approx. 45cm into the room where the stove is (even on a silver flue this protruding section will usually be black unless otherwise specified). The flue below this will usually be single skin black vitreous steel pipe.

Internal stove pipe will usually travel vertically 50cm before changing to 45 degrees and passing through the wall to outside.

Twin wall flue requires NO sealants or pastes or glues. It is "clip together". Nice and simple.

NO base wall support required if the height of the flue is below 6 mtr .