At Billing Chimneys we will only recommend the Schiedel Isokern pumice lining system in thatched properties. There are two theories regarding the cause of chimney fires and the pumice system deals with both scenarios much better than other flue lining systems.
A recent study by Burgoynes loss adjusters came to the conclusion that most chimney fires start within a short time of the fire being lit and this suggests that it is sparks landing on dry thatch that is the cause of this. It is important therefore that the flue is well insulated so that it warms up quickly and that the draught travelling through the flue encourages any sparks to fly clear of the roof covering.
Pumice is a natural insulator and warms up quickly and, with the additional insulation provided by the leca insulation that surrounds it and fills the void between the new liner and the existing brick flue, this creates a safe and efficient flue. Other flue lining materials may have little or no insulation and will heat up more slowly. The pumice system has many other advantages but it does require opening up the flue to complete the installation though the openings are small and the Billing Chimneys team will make good and replaster as necessary. If the chimney stack is on an outside wall these openings can be made without disturbing any interior surfaces.
The other theory on the cause of chimney fires focuses on the heat transferred as the flue travels through the thatch. The thatch itself is also an insulator so that if heat is being transferred from the flue into the thatch high temperatures can arise. There are alarms that can be placed in the thatch adjacent to the flue to sound before dangerous temperatures are achieved.
As described above the pumice being an excellent insulator keeps the internal temperature of the flue high but the external surfaces cool and again with the leca insulation allow little increase in temperature in the thatch. Pumice is also a good long term solution to the creation of a continuous reliable flue.
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