Calculate excavation first
Use the excavation limits, depth, slopes or shoring limits, and working space rather than finished basement dimensions alone.
Separate bank excavation from loose hauled volume.
Take off footings and walls
Calculate continuous footings and wall sections with their actual dimensions.
Subtract openings only when they materially reduce placed concrete and match the construction method.
Add the basement slab
Calculate slab area and thickness separately from wall and footing concrete.
Include subbase and moisture-control layers as separate takeoff items.
Plan backfill separately
Backfill volume is the space remaining outside the completed foundation, adjusted for the selected material and compaction.
Do not assume all excavated soil is suitable or reusable.
Check temporary and permanent conditions
Groundwater, shoring, slopes, drainage, soil stability, and access can control excavation work.
Quantity calculations do not replace geotechnical or structural design.