5 Inch Twin Wall Structural Locking Band
5″ Inch Sturctural Locking Band
See attached for the BFMCA guidance document which references Document J of the building regs. On page 9 under heading ‘Chimney Heights and Termination’, the text states ‘The maximum freestanding stack height above the roof for a traditional masonry chimney is 5.4 times the narrowest horizontal part of the chimney. In the case of stainless-steel system chimneys, the manufacturer’s installation instructions should be consulted; however in most cases it will be around 1.5 metres. This measurement is taken from the last point where the chimney stack passes the through or past the edge of the roof up to the chimney capping or termination. Tall chimneys may need bracing, always consult the manufacturer for advice’.
We recommend a locking band should be fitted to any joint above the height of 1.5m to add sufficient structural support.
