Where the chimney is passing through a combustible floor into a habitable room i.e. bedroom, in which the chimney is enclosed in a shaft, a ventilated fire stop plate must always be used.
In a bungalow scenario where the chimney is passing through the ceiling directly into a ventilated attic space, a non ventilated fire stop plate may be used on the ceiling. A distance to combustibles of 60mm must be maintained from the outer wall of the chimney.