A good quality, insulated flue will maintain flue gas temperature and minimise tarring. The most popular flue is twin walled, sectional stainless steel that can be easily erected. A pumice liner is an alternative which can be bricked around to match your property.
The prevailing wind, the contours of the land, adjacent buildings and clumps of trees can prevent the gases clearing. It is usually sufficient to build the flue 1.2 meters above the obstruction to avoid complications.
EG Measure from the floor to the ridge of the adjacent building, deduct the height of your chosen heater and add 1200 mm to give the length required.
We can supply a flue starter pack including an appliance connector, a top stub plus 3m of flue and the connecting collars and wall brackets. Further one metre lengths can be added as required.