The scope of applicable substructure is as follows:-
1.1.1 Standard foundations
• Standard foundations up to and including the damp-proof course.
1.1.2 Specialist foundations
• Load bearing foundation piles and caissons.
• Inserting additional foundation support under and around existing foundations.
1.1.3 Lowest floor construction:
• The entire lowest floor assembly below the underside of screed or lowest floor finish.
1.1.4 Basement excavation
• Bulk excavation required for construction of floors below ground level.
1.1.5 Basement retaining walls
• External basement retaining walls in contact with earthwork up to and including the damp-proof course.
• External basement retaining walls consisting of shoulder to shoulder piles or other vertical construction, which are subsequently partially excavated on one side to form retaining walls which obtain their stability from the embedded lower portion.
Almost all projects will involve some design work to one or more of these classifications, which can be informed by building LCA.
If the BREEAM assessment covers only part of the building, such as an upper floor, but substructure works are part of the wider building design then it is still applicable to the assessment, see KBCN1172.
Where the substructure design includes only reuse of existing construction products on site it is often still applicable to the assessment, see KBCN1174.
If the extent of, or options for substructure are relatively limited then it would be advantageous to maximise the number of hard landscaping options and minimise the substructure options appraised for this credit.
If the above guidance is followed carefully, and the assessor determines there is no applicable substructure, then the assessor should send a technical query to BREEAM explaining the basis of this conclusion. BREEAM will clarify how to proceed with this credit.
