The classic site scenario: the supervisor says “go ahead, paperwork later”, the contractor builds it, and the employer refuses payment for want of an approved variation. Who is right turns on a single thing: whether that instruction was evidenced in a form the contract recognises.
Legal basis
- Law on Construction 50/2014/QH13 (amended by Law 62/2020/QH14)
- Decree 37/2015/ND-CP on construction contracts (amended by Decree 50/2021/ND-CP)
- Civil Code 91/2015/QH13
The principle: no approval, no payment
Construction contracts under the Decree 37/2015/ND-CP framework run on the principle that work outside the contract scope is performed and paid only with the employer’s approval (or a duly authorised person’s) following the contract procedure: variation proposal, quantity/price assessment, written approval, then execution. A contractor who proceeds on its own bears the risk of full refusal for that part, however necessary the work was to the project. The principle protects the employer against “reverse variations” — build first, force payment later.
Exceptions accepted in practice
Three exceptions are commonly weighed: (1) an oral site instruction in an emergency (collapse risk, safety, spreading damage) which the contractor confirmed in writing within the contract period without objection from the employer/supervisor; (2) work that, correctly interpreted against the drawings/specifications, lies within the original contract scope — then it is not a variation at all but work already in the price; (3) the employer accepted and uses the result and directly benefits — benefit alone creates no automatic payment right, but it is a strong argument for payment of fair value in many cases.
Instruction evidence: cases are won on site paper
The contractor must assemble: progress-meeting minutes recording the instruction, construction and supervision diaries, confirmation emails/letters, time-stamped photos of process and result, and acceptance records for the work. The employer wins with: the contract’s variation-approval authority clause, proof the instructor lacked authority, and a written objection made as soon as it learned of the unapproved work. The operating lesson for both sides: every oral instruction must be “closed” in writing within 24–48 hours, and a contractor should never start a major variation on a spoken sentence alone.
Related reading on flaw.vn: article FDI-LC-4759 covers the general framework of this topic — this article deals only with the specific angle in its title.
Frequently asked questions
If a contractor does additional work on its own, will it be paid?
In principle, no: work outside the contract scope without the employer’s approval under the contract procedure is at the contractor’s cost risk. Weighed exceptions include emergency instructions confirmed in writing on time, work properly interpreted as within the original scope, and cases where the employer accepted and uses the result — where fair-value payment is likelier but never automatic.
Is verbal approval valid?
Whoever the contract authorises: usually the employer or its written delegate within the delegated limits. A supervision consultant’s instruction counts as variation approval only if the contract/letter of authorisation grants that power. That is why these disputes always start by reading the authority clause and the site delegations.
How is the unit price for additional work calculated?
Assemble the site-paper chain: meeting minutes and diaries recording the instruction, the written/email confirmation of the instruction (especially if sent within the contract period and not objected to), acceptance records, and proof the employer used the result. An oral instruction with no written confirmation anywhere is the contractor’s weakest possible position.
How to control additional work?
The surest way: a site rule of “no writing, no work” for every variation above a value threshold; a 24–48-hour oral-instruction confirmation form; and a published list of who may approve variations, given to both supervisor and contractor. These three steps remove most variation disputes at the root.
This article has been quality-reviewed by the FLAW AI Legal Council
