These liners are made by Isokern from pumice which is a volcanic rock that has amazing resistance to high temperatures and exceptionally good insulating properties, which is just what you want for a flue liner.
They are also CE marked and included in the HETAS list of approved products for use with solid fuel and wood burning appliances.
They are lowered down the chimney in the same way as the rigid metal liners and then surrounded with a lightweight leca insulating concrete backfill.
It is important that the flue in the chimney is big enough to accommodate the liners and at least 25mm thickness of backfill. If bends have to be fitted inside the chimney it is usually necessary to cut an access hole through the chimney walls and then make good afterwards.
Many people in the trade consider these liners to be virtually permanent and ideally suited for wood burning stoves. These liners are usually best installed by qualified chimney engineers.
These liners can also be used to build new chimneys, and we carry large stocks of the most popular diameters.
More details are given in the Isokern chimney relining leaflet and the main Isokern chimney brochure below.