Basement storey
A storey with a floor that, at some point, is more than 1200mm below the highest level of ground beside the outside walls. (However, see Appendix B, paragraph B26c, for situations where the storey is considered to be a basement only because of a sloping site.)
Approved Document B Volumes 1 and 2, Appendix A (page 133, page 144)
Related terms
Definitions are taken from Approved Document B (fire safety). Contains public sector information licensed under the Open Government Licence v3.0.
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