Just a quick one. I can't find the required dimmensions for chimney height. I think that if the chimney is under 1500mm horozontally from the apex it must be 600mm higher than the apex and if it is under 2300mm from the apex it must be as high as the apex. Is this broadly right. I know i once found a link which explained it but I cant find it now.
Thanks
David
Thanks
David