Commercial
What is a bill of materials?
A bill of materials is the list of everything a scaffold is built from — tubes, boards, fittings and components, by type and quantity. It is what the job is priced from and what the yard loads to.
Traditionally the bill is worked out from experience and a drawing. Where the structure has been modelled, it comes out of the model, which means the list the quote was priced from and the list the wagon was loaded to are the same list.
That matters because the two are normally different and the difference is absorbed silently — as material that went to site and was never charged, or as a second trip that nobody costed.
A bill is also a description of a configuration. It reflects the bay lengths and lift heights the scaffold was designed at, so it is evidence of what was built alongside the drawing and the compliance sheet.
It is not an assessment. A material list can be produced for a configuration that should never be built; whether the arrangement is sound is a question for the compliance sheet or a competent designer, not for the list.
What goes wrong on site
- Pricing from one list and loading from another, so the discrepancy never becomes visible.
- Treating a generated bill as confirmation that the structure is adequate.
- No bill written down at all, which makes it impossible to work out afterwards why a job that priced well made nothing.