Head contractor
A head contractor is the main builder responsible for delivering a project, contracting directly with the client and engaging subcontractors to complete the work.
Ask Chalkline about this →A head contractor (also called the principal contractor on WHS documents, or simply the builder on residential jobs) is the party that contracts directly with the client to deliver the construction project. The head contractor is responsible for managing the site, engaging subcontractors, coordinating trades, and meeting the contractual obligations to the client.
In the Security of Payment Acts, “head contractor” specifically refers to the party that is engaged directly by the principal (the client) and that in turn engages subcontractors. This distinction matters for retention trust account obligations: NSW requires head contractors on projects over $20 million to hold subcontractor retention money in a dedicated trust account.
On a standard residential house build, the licensed builder acts as the head contractor. On larger multi-residential or commercial projects, the head contractor is often a construction management company or principal building firm.
Also known as: principal contractor (WHS context), builder (residential), main contractor.
Category: Contracts & commercial.
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Last updated: 2026-05-08. Verified: 2026-05-08. Quarterly review for currency.