What Is a Bill of Materials (BOM) Used For in Construction?
How a BOM lists parts and materials for fabrication and procurement, and how it differs from trade-level pricing documents.
BOM definition
A bill of materials (BOM) is a structured list of components, parts, or material assemblies required to build or install something—often at part-number level for manufacturing, prefabrication, or systems.
In construction, BOMs appear in modular builds, joinery, steel packages, and MEP assemblies where procurement needs exact items rather than only trade lump sums.
Unlike a trade-level BOQ line, a BOM may include quantities per assembly, alternates, supplier part numbers, and revision history so fabrication and purchasing stay aligned.
Typical uses
Teams use BOMs for purchasing, kitting, fabrication drawings, and version control when parts change. ERP and PLM systems often own the BOM lifecycle.
A trade BOQ line might say “supply and fix suspended ceiling 600×600”; a BOM might list tiles, grid, hangers, and accessories separately.
On site, subcontractors may maintain an internal BOM even when the employer’s contract references BOQ rates—especially for design-and-supply packages.
BOM vs BOQ in one sentence
If you need to price measured work for tender comparison, you lean on BOQ structure; if you need to order or fabricate exact parts, you lean on a BOM.
Miscommunication happens when procurement uses BOM quantities while the contract pays against BOQ items—keep revision IDs and responsibilities explicit in each package.