How far above the chimney should the flue liner protrude?

The correct answer regarding how far above the chimney the flue liner should protrude is that it must be a minimum of 50mm. This specification is crucial for ensuring that the flue liner effectively vents gases and smoke away from the structure without allowing them to re-enter the home.

Protrusion of at least 50mm helps to ensure that the flue is sufficiently above the roofline, which can prevent downdrafts and improve the overall performance of the chimney system. Additionally, this height requirement helps to protect the flue liner from damaging weather conditions and ensures that it meets safety regulations for adequate ventilation. Proper installation with respect to this height reduces the risk of chimney fires and improves the efficiency of fuel use.

Having a standard measurement, like the minimum of 50mm, helps align installers with safety codes, thereby facilitating consistent and safe building practices.