Note
Defect List at Billing Time
When the billing stage is due and the invoice should go out, a defect list from the main contractor arrives instead of a signed acceptance form. The invoice cannot go out. The billing pin sits unmoved.
Understanding why this happens and how to manage the gap between submitting a billing stage and receiving signed acceptance is one of the more practical skills in Thai subcontracting.
Why does a defect list appear at billing time?
Two reasons, and they are not the same thing.
The first is genuine: work that does not meet the agreed standard. A zone completed to 90 percent quality, welds that need grinding, a surface finish that was accepted on one project and rejected on another because the acceptance criteria were never written down. Real defects exist, and they are the subcontractor’s responsibility to fix.
The second is administrative: main contractors who use a defect list as a first response to any billing submission, regardless of quality, because it starts a new timeline rather than a payment clock. In Thai commercial construction, this is a known pattern. A main contractor with their own cash flow pressure finds it easier to return a list and wait than to sign acceptance and begin a 45-day payment cycle.
The distinction matters. Treating every defect list as genuine wastes time and signal. Treating every list as bad faith damages working relationships and misses real quality issues.
What makes a defect list hard to dispute?
When acceptance criteria were agreed in writing before work started, a defect list is verifiable. Either the zone meets the spec or it does not. The discussion is short.
When criteria were agreed verbally or not agreed at all, the main contractor’s site person becomes the standard. Whatever they say on the day they look is the standard. That is the condition most subcontractors find themselves in when the first defect list arrives.
The acceptance form that holds up references criteria agreed before the work began. Without that reference, the form is a signature on a standard nobody wrote down. Agree the criteria before each stage starts, check before the formal submission, and submit with dated photographs. None of this prevents a defect list, but it determines whether the list is a discussion or a wall.
How do you separate a genuine defect from a payment objection?
Walk the site with the main contractor’s site supervisor, not their billing team. Request that every item on the defect list has a specific location, a photograph where possible, and a reference to the specification it fails against.
A genuine defect is pointable. Zone seven, bracket row three, weld gap exceeds 2 mm per drawing SK-12. That is a real item.
A vague item reads differently. “Finish quality not acceptable across zone seven” cannot be actioned without further questions: which part, what standard, acceptable on a trial sample? When most items read this way, the list is serving a different function.
Ask for a written response deadline. Many Thai subcontracts do not specify how long a main contractor has to respond to a billing submission. If yours does not, send a written follow-up within two to three working days of submission and log every exchange by date.
A worked example: aluminium cladding, twelve zones
A subcontractor installs aluminium cladding across twelve zones. Billing stage three covers zones seven through nine, billed at practical completion of all three.
Zones seven and eight are complete. Zone nine has one panel with a surface defect. The subcontractor submits the billing stage with photographs taken the day before.
The main contractor returns eleven items across all three zones. Two are genuine: the panel in zone nine and a sealant gap at zone eight. The remaining nine read as vague phrases like “cladding alignment to be checked” with no specification reference.
The subcontractor arranges a site walkthrough with the main contractor’s supervisor the following morning. Seven vague items cannot be located. Two marginal cases are confirmed within tolerance on the spot. Zone nine and zone eight are fixed within two days.
A revised acceptance form covering all three zones is signed on day three. The invoice goes out the same afternoon. The billing pin holds to within three working days of its planned date.
Without the walkthrough, the subcontractor would have spent a week responding in writing and the billing date would have moved by two to three weeks. The pre-submission photographs also mattered: they showed the zones were in acceptable condition before the submission date.
What to do before the next billing stage
Conduct a pre-acceptance walkthrough three to five working days before the planned billing date.
Walk the zone with your own foreman. List every point that might draw a comment, fix the ones that are fixable, then photograph the zone the day before submission. Send those photographs as part of the acceptance package.
When the main contractor’s site person has already informally seen the zone and said nothing, a formal defect list after submission is a different conversation. You have dated photographs showing the zone’s condition before the submission date. The burden of showing what changed shifts.
This takes roughly one hour on a typical installation zone. That hour almost always costs less than the delay it prevents.
FAQ
Can a main contractor withhold an entire billing stage because of one defect?
In practice, yes. A contract that ties full stage payment to complete acceptance of all work in the stage gives them that right. Some contracts allow partial payment for completed and accepted work, with the remainder held pending the defective item. If yours does not specify this, partial payment is not implied. The time to negotiate it is at contract signing, not when the defect list arrives.
How long does a main contractor have to respond to a billing submission?
Many Thai subcontracts do not specify a response period. Without a written term, the main contractor can take as long as seems reasonable, which in practice can run several weeks. Before signing, ask for a specific acceptance response period, typically five to ten working days, and have it written into the contract. If the contract is already signed without one, a written follow-up two to three days after submission starts a paper trail even without a legal deadline.
What if the defect keeps reappearing after we fix it?
A recurring defect on the same item is either a workmanship problem needing a root-cause fix rather than a patch, or an administrative pattern. If the fix was correct and the defect reappears on re-inspection, request a joint inspection with written notes from both parties. A defect that cannot be demonstrated at a joint inspection after a documented fix is not a straightforward reason to withhold acceptance.
If you want to see how a pre-submission check and written acceptance criteria sit on a live project timeline, a 45-minute call is a practical place to start. We walk one project together, set the acceptance checkpoints against your billing pins, and agree a pre-submission routine that fits your site team.