Rigid Refactory Liners

This is the most traditional method of lining using refractory concrete, clay or ceramic liners of the same type commonly used in new build. There are also some pumice liners designed specifically for relining. The chimney has to be opened at frequent intervals to insert the liners, essential if there are bends in the flue. The resulting dust, mess and subsequent redecorating are not popular with the householder.

 

If the old flue is large enough and straight it is often possible to lower liners down from the top without opening the flue inside the house.

The liners must either have rebated and socketed joints or steel locking bands. (NB – rebated and socketed joints must be fitted the correct way up. Rebates are there to prevent any condensates running down the flue from leaking out, therefore the socket end must be uppermost and the spigot end fitting down inside the lower pipe). A possible drawback with this method is the wall thickness of the liner, usually 20-25 mm. Twice this dimension plus a clearance needs to be deducted from the size of the original flue, resulting in a much reduced flue cross section. For a nominal 225x225mm flue this probably means only a 150mm or 175mm flue can be achieved. This reduced size will be too small for an open fire so a closed appliance may have to be fitted. Clay liners used in this method must comply with BS EN 1457 : 1999.

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