Chapter 2 recap
Quantities and cost
The key takeaways from this chapter’s 2 lessons.
Quantities you can trust
- Every measured element needs a classification code and a type whose name says what it's made of.
- Check for duplicates across discipline models before taking quantities (the same wall in architecture and structure).
- State net or gross, and how openings, junctions and layers are measured; the model's default may not match the measurement rules.
- Every quantity report says what came from the model and what didn't.
From quantities to an estimate (5D)
- The chain is: classify, extract, map to cost items, price, then complete with what the model can't give.
- The biggest benefit is change: comparing two revisions shows the cost of a design decision in hours.
- Elemental structures (NRM 1, UniFormat) suit early estimates; trade structures (NRM 2, MasterFormat) suit tenders.
- A 5D estimate covers modelled work only; preliminaries, risk and method still come from the estimator.