Warning signs a variation approval may be disputed later
The approval that disappears
A site supervisor tells you to crack on with extra work. A project manager waves you through. The client sends a text saying go ahead. You order materials, put your crew on the job and complete the variation.
Then the invoice goes in and suddenly the story changes, no signature, no written approval, just your word against theirs. This situation happens often in construction and is usually avoidable if you recognise the warning signs before the work starts.
Decisions get made quickly on site. The problem arrives when someone decides they do not want to pay and a verbal agreement becomes easy to dispute.
Check who actually has authority
The person telling you to proceed may not have authority to approve variations under the contract. A site foreman, junior project manager or the client's friend may genuinely believe they can authorise the work, but their approval may not bind the party responsible for payment.
Before starting variation work, confirm who is named in your contract as the person authorised to approve changes. If the approval is coming from someone else, ask whether that person has been given written authority to act on behalf of the principal or head contractor.
If you cannot confirm authority, you are taking a risk that the variation will later be disputed. That risk grows when the person giving approval is not the person who will sign the payment certificate or release funds.
Look at how the instruction arrives
An unclear instruction is an early warning. If the scope, price or timing is vague, or the client asks you to start immediately without discussing cost, the variation is more likely to be disputed when your invoice arrives.
A text message that says 'go ahead' without specifying what you are being asked to do, how much it will cost or when payment is due leaves room for disagreement later. The same applies to a verbal conversation on site that is not followed up in writing.
If someone is reluctant to put the approval in writing, or says you can sort out the paperwork later, treat that as a warning sign. Delays in documenting variations often lead to disputes about whether the work was agreed, what the scope included and what price was accepted.
Recommended documentation practice
Most building contracts require or strongly recommend that variations be documented in writing before work starts. Documented records help establish what was agreed, by whom and when.
Even where your contract does not mandate a particular process, written confirmation before starting protects both parties. Without it, proving what was agreed becomes harder and more expensive if payment is disputed.
Treat documentation as a practical step to reduce commercial risk, not simply a legal formality. The clearer your records, the stronger your position if a variation is later challenged.
What to do before you start the work
Gather the evidence before you commit. If the variation has been approved verbally or by text, send a written summary to the person who approved it. Describe the work, state the price, note any effect on the completion date and ask for written confirmation.
Keep the response. If the client or their representative confirms the details in writing, even by email or text, that record becomes evidence of what was agreed. If they do not respond, or they respond with different details, you know there is a problem before you have spent money on materials or committed your crew.
If your contract requires variations to be approved in a specific way, follow that process. Do not assume a verbal approval is enough, even if the person giving it is senior or has approved other variations in the past. Contracts can change, authority can be withdrawn and memories fade.
Source: NSW Fair Trading: Contracts for residential building work
Recognise the commercial pressure
Clients and head contractors sometimes create urgency to discourage documentation. You may be told the work must start today, that a delay will hold up the whole project or that written approval will follow once the job is underway.
These situations create commercial pressure to proceed without adequate records. That pressure may be genuine, some variations do need to start quickly, but it does not remove the risk that the work will later be disputed.
When urgency is used as a reason not to document a variation, consider whether the risk is proportionate to the value of the work. A small urgent repair is different from a significant scope change that will take weeks and cost tens of thousands of dollars. The larger the variation, the greater the need for a clear written record before you start.
What to keep in your file
If you proceed with a variation that has not been formally documented, keep every piece of evidence that shows what was agreed and who approved it. That includes text messages, emails, site instructions, photos showing the client or their representative present while the work was being done and any conduct after completion that suggests the work was accepted.
Separate what the records actually establish from what you remember. A text that says 'thanks' is not the same as a text that confirms a price. A site visit where the client saw the work is not the same as a written acknowledgment that the variation was requested.
Good records do not guarantee you will be paid if a variation is disputed, but poor records make recovery much harder. If you cannot show what was agreed, who approved it and when, your position weakens quickly.
The decision point
The critical decision is whether to start variation work when the approval is unclear, verbal or coming from someone without confirmed authority. That decision should be based on the value of the work, the quality of the evidence you have so far, the reliability of the party giving approval and your assessment of the commercial relationship.
There is no universal answer. Some relationships are strong enough that verbal approvals are rarely disputed. Others are not. The useful question is whether you are prepared to carry the cost of the variation if payment is later refused.
If you are not prepared to carry that risk, do not start the work until you have written confirmation of the scope, price and authority to approve. If the client will not provide that confirmation, you have learned something important about the variation before you have spent money on it.