Construction Variations and the Bill of Quantities
How BOQ lines anchor variation pricing and what to document when scope changes.
Linking variations to BOQ
Variations reference base BOQ items, dayworks, or new measured items. Clear records of instructed changes protect both parties.
Rates in the BOQ may apply to similar work; contracts define how new rates are built when no match exists.
Always capture instruction date, drawing revision, and site conditions—rates assume a basis; if that basis shifts, the valuation method may shift too.
Records that hold up
Photos, marked-up drawings, daily logs, and RFIs form the narrative that supports quantity changes.
Agree measurement method upfront for complex variations (e.g. rebar changes after pour) to avoid two different quantities at final account.
Time and prolongation
Some variations drive programme extension; others are absorbed—contract clauses differ on concurrent delay and float.
Separate the variation valuation (scope/quantities) from prolongation costs (prelims) unless the contract rolls them together.