Note
Set Acceptance Criteria Before Work
The acceptance inspection should be a formality. When the criteria for a completed stage were agreed in writing at project start, the inspector’s job is to confirm what both sides already know is true. When the criteria were never agreed, the inspection becomes the first time anyone has formally discussed what done means.
That difference determines whether a stage gets signed off in one visit or accumulates a list of items that each take two to three days to chase back to someone with authority to resolve.
Why does the dispute arrive at the inspection, not before?
During mobilisation, both sides have more pressing things to discuss: programme dates, material deliveries, site access. The acceptance criteria for each billing stage rarely makes the agenda.
The problem deferred surfaces when the inspector arrives. The main contractor’s engineer holds one set of expectations about what the completed stage must look like. The subcontractor holds another, based on the BOQ description and what was actually installed. Where those two sets overlap, sign-off is fast. Where they diverge, the inspector writes a list.
A list generated at inspection has a particular quality: it reflects what the engineer noticed on the day, not what the subcontract actually required. Items appear that have no reference in the BOQ, are not in the specification, or belong to an adjacent trade’s scope. Working through those items takes days. The billing stage waits, and if the delay pushes past the billing cutoff, it carries the full credit period on top of that.
What do acceptance criteria actually need to cover?
For a typical installation or fit-out stage in Thai subcontract work, agreed criteria need to answer four questions.
Which scope is included. Not just the zone name, but the specific BOQ items. A stage that lists “zones A and B complete” without specifying which trades are included creates uncertainty about whether the electrical first-fix or the plumbing rough-in is the subcontractor’s scope or someone else’s.
What standard applies. Most subcontracts reference a specification document but leave tolerances unstated. A partition that varies by 4mm over a 3-metre run may be within market tolerances but is not written anywhere. Agreeing one line on acceptable tolerances removes the call to a senior engineer when the inspector finds that variance.
What is excluded from this stage. A zone where one section is complete and one is still in progress needs a clear written boundary. The inspector who checks zone A and walks into zone B needs to know where their check ends, or their list will include items from a stage not yet submitted.
Who has authority to sign off. The main contractor’s site engineer, the project manager, the owner’s representative, or a combination. Knowing this before submitting the inspection request saves one round trip at every stage.
A worked example: same zone, two different starting points
Two finishing subcontractors are working in adjacent zones of a commercial office fit-out.
The first discussed acceptance criteria with the main contractor’s commercial team during the project kick-off. The result was a one-page document per stage: the BOQ items covered, a note that “complete” means all items installed with a surface finish ready for painting, and a tolerance reference from the specification. When the inspector arrived for zone A, they checked against the agreed criteria. Sign-off took 40 minutes.
The second submitted the inspection request after the zone was finished with no criteria agreed upfront. The inspector arrived, checked the zone, and noted seven items: two surface imperfections, one joint gap, a light fitting not yet installed (belonging to an electrical subcontractor), and three items that did not appear in the finishing subcontractor’s BOQ at all. Clarifying which items were whose responsibility took four days of email. The stage was invoiced 14 days later than zone A and landed in the following payment cycle.
Both zones finished on the same calendar date. The billing date difference came from a document prepared before the first crew member arrived.
How do you get written criteria agreed before work starts?
The practical approach is to attach the criteria to the mobilisation meeting. Most main contractors hold a subcontractor briefing or kick-off before work begins. Adding a one-page criteria summary to that meeting’s agenda is easier to accept than a standalone request that arrives later and reads like an attempt to reopen the signed contract.
One page per stage type is enough. If the main contractor will not confirm in writing at the meeting, a summary email sent afterward and not contradicted within five working days becomes the working reference. A record produced before work starts is an admin document. A record produced after a dispute is a claim document. They are handled very differently.
What does a one-page criteria document look like?
Three sections do the job.
Stage covered: a specific reference, such as “Stage 2, zones C and D, as defined in the BOQ.”
Completion conditions: a bullet list of the BOQ items that must be installed for this stage, and any tolerance reference from the specification. One sentence per item is enough.
Exclusions for this stage: a list of items or zones not included in this submission, so the inspector knows where their check ends.
The document is not a legal contract. It is a shared reference. Both parties sign one line at the bottom: “Agreed acceptance criteria for the above stage.” That signature converts a verbal understanding into a working document before the work begins.
FAQ
What if the main contractor will not commit to written criteria before mobilisation?
Send a summary email to the commercial contact after the kick-off meeting stating what you understand the criteria to be. If it is not contradicted within five working days, it becomes the reference document. Weaker than a countersigned agreement, but stronger than a verbal conversation, because it shows both parties had the chance to object and did not.
Are photographs a specific enough standard for surface quality?
Photographs from a completed reference zone are the most practical standard for surface quality and finish level. They are concrete, cannot be argued as subjective, and can be sent to the inspector before any inspection request. A photo standard works alongside written criteria, not instead of them: the criteria define the scope, the photographs show what acceptable finish looks like on that specific project.
Can acceptance criteria be included in the subcontract itself?
Yes, and that is the strongest position. A schedule attached to the subcontract that lists stage acceptance conditions turns the criteria into a contractual obligation agreed before any work starts. Adding a schedule at contract stage is more practical than trying to introduce criteria after mobilisation, when the main contractor’s commercial team considers the contract settled and any addition reads as a renegotiation.
If you want to check whether the acceptance criteria on a project you are currently running were documented before work started, a 45-minute call is a practical starting point. We open one project together and compare what was agreed at the start against what is being inspected now.