Key takeaways
- A purchase order records what the builder agreed to pay for a specific job, which an invoice cannot do on its own.
- Tie every order to a job code that does not change once the job starts, so the bookkeeper can allocate cost without guessing.
- Raise the order before the supplier confirms the load, because the habit collapses once the truck is already on its way.
- Check each delivery against the order on arrival and note any shortage or damage on the docket before anyone signs.
- Keep the order, docket and invoice together in the job folder and review a sample each month to find where the habit has slipped.
A purchase order is the cheapest control a small builder can put on spending, and it is the one most often skipped. The usual pattern is familiar to anyone who has run a job. The site lead rings the merchant from the ute, asks for framing, fixings and a couple of sheets of ply, the counter agrees, and the invoice arrives weeks later with no job attached to it. By then the cost sits somewhere in the ledger, the variation cannot be traced, and nobody can say whether the price was the one anybody agreed to.
This article sets out a light purchase order habit that a small team can keep up without a software project. It is built around one idea: every order is tied to a job code before anything is delivered, and the order is the record of what the builder agreed to pay. It is deliberately narrower than the wider questions about supplier accounts and business systems. Here the only question is how an order gets raised, approved and matched to what arrives on site.
The commercial cost of skipping the habit rarely shows up in one place. Materials that do not match the estimate get absorbed into the job margin. Over-ordering turns into offcuts that nobody logs. Duplicate deliveries sit in the laydown area until the weather gets them. None of this looks like a disaster on its own, which is exactly why the habit is hard to keep without a simple structure around it.
Why the order matters more than the invoice
An invoice is a supplier’s request for money. It shows what was delivered and what it cost, but it cannot show whether anyone at your business agreed to that price, which job the materials belong to, or whether the quantity matches what the site asked for. A purchase order answers those questions before the goods leave the yard. It is the builder’s side of the transaction written down, and it is the document you check the invoice against when it arrives.
The distinction matters most at the final account. When a client asks why the cost of a job moved, the honest answer is only as good as the paperwork behind each line. If every material traces back to an order that names the job and the agreed price, the answer takes minutes. If the orders were made by phone and the invoices came in with vague descriptions, the answer becomes a negotiation, and the builder usually carries the difference.
Where the order sits next to a supplier account
Many builders already hold an account with a merchant, a steel supplier or a hardware chain. The account is a credit arrangement. It says you are allowed to buy from that supplier and sets the terms on which you pay later. The purchase order sits on top of that relationship and answers a different question. The account says who you can buy from and when the bill falls due. The order says this load is for this job, and this is the price we accepted for it. The credit terms themselves are covered in supplier accounts and credit terms for builders, so this article stays on the order.
Keep those two things separate in your head and in your filing. A well-run account does not stop a site lead ordering the wrong quantity, and a purchase order does not change the payment terms. If you find yourself arguing with a supplier about what the price was, the order is the place to settle it. That is why it has to exist before the delivery and not after it.
The table below sets the two side by side, because they are easy to confuse when both sit in the same supplier statement.
A purchase order and a supplier account do different jobs
| Purchase order | Supplier credit account |
|---|---|
| Records what was agreed for one job | Sets the standing terms on which you can buy |
| Raised before the goods are committed | Used when goods are delivered and invoiced |
| Shows which job carries the cost | Shows what is owed to the supplier overall |
| Is the document you check the invoice against | Governs when payment falls due |
Tie every order to a job code
A job code is the simplest tool in the whole system. Each live job gets a short, stable reference that appears on every purchase order, every delivery docket and every invoice that comes back. The code does not need to be clever. It needs to be the same code everywhere, and it needs to be the thing your bookkeeper uses to allocate cost. A common mistake is to use the client’s name, which changes when a job is sold on or renamed, or the street address, which may be written differently on the council file and on the site sign. Pick a code that will not change once the job starts.
Shared costs need their own code. A hire trailer, a general consumables order or a bulk delivery of fixings that serves several jobs should not be forced onto whichever job happened to be open that day. That kind of allocation is how a job looks profitable in the spreadsheet and loses money on the ground. Put the shared cost under its own heading, then spread it across jobs deliberately at month end, with the basis written down so the split can be explained later.
When the code is used consistently, the figure below captures the idea the rest of the habit depends on.
What an order must say before it leaves the office
A useful order carries only the details that let someone else pick it up and check it. It needs the supplier, the job code, the delivery address and the date the materials are needed by. Each item should be described the way the supplier will recognise it, with the grade, finish or size written in words where it matters, together with the quantity and the agreed unit price. It should name who raised it and who is authorised to receive it on site. If the price is not yet fixed, the order should say so, rather than leaving a blank that somebody will fill in later.
Describe the requirement, not a guess at the product. Where the design or specification names a material, take the wording from the documents and not from memory of what the merchant stocked last year. Where the builder chooses an equivalent, the order should say that the product is an equivalent and record who approved the substitution. Quoting a product by name and then delivering a cheaper one is one of the most common sources of argument when a defect appears years later, and the order is the first place anyone will look.
Keep the order short enough to fill in with dirty hands. A template with a dozen fields that nobody completes is worse than a plain one that everybody uses. The fields that matter are the ones that let the bookkeeper and the client’s representative understand the purchase without a conversation.
Raise it before the phone call
A purchase order habit only works if it comes before the commitment. Once a supplier has the load on a truck, the order is a formality, and the office drifts back to signing for the delivery after the fact. The rule that holds up is that anything above a value the builder sets in advance gets an order number before the supplier confirms, and anything below that value can be raised on the spot by the site lead, using the same template, still with a job code on it.
The threshold is a business decision, not a figure to copy from someone else’s procedure. Set it low enough that a routine purchase does not need the owner to be consulted, and high enough that a large commitment always does. Write it into the site box or the office procedure, and review it when prices move or the size of the jobs changes. The threshold is not there to slow the site down. It is there so that the people who carry the margin know what is being committed in their name.
The sequence below is the one that survives a busy week. Each step can be done by the site lead from a phone, and none of them needs the office to be open.
Raising an order someone else can check
- 1Confirm the job codeUse the code the bookkeeper allocates to, never the client name or the street address.
- 2Describe each itemWrite the grade, finish or size in words, with the agreed quantity and unit price.
- 3Approve before the callAnything above the agreed threshold gets an order number before the supplier confirms.
- 4Check the truck on arrivalCount what is delivered, note shortages or damage on the docket, and sign only for what is there.
- 5File the set togetherKeep the order, docket and invoice in the job folder for the bookkeeper and the final account.
Who approves, and how far a site can go without asking
Approval is about accountability, not hierarchy. On a small business the owner may be the only approver, and that is fine as long as each approval is recorded. The question to settle is who can commit the business to a price and who can only request a quantity. A site lead who can change an order on the phone without any record has effectively handed over control of the job margin, and that is usually the first place an overrun starts. An approval recorded in a text message is better than none, but a short order form that the approver initials is better still.
Variations need their own treatment. When a client asks for a change that adds materials, the purchase order should refer to the agreed variation and should not stand on its own. If the variation has not been agreed in writing with the client, the materials are a cost the builder may end up carrying. Check the contract for how variations must be documented before buying the extra items. The consequence of getting this wrong, a cost nobody can recover, usually surfaces at the final account, when it is too late to fix.
The mistake that costs the most. Buying extra materials on a verbal instruction, with no job code and no agreed variation behind them. The client never signed for the extra cost, and by the final account the builder is the only one left paying it.
Matching the delivery to the order
When the truck arrives, the docket should be checked against the order before anyone signs. Check the supplier, the job code, the items and the quantities. Count what is actually on the truck, not what the docket says is on it. Note any short delivery, damage or substitution on the docket itself, and photograph damage while the load is still in place. A signature on a docket is a statement about the goods, and once it is signed the argument becomes harder to win. Many merchants now take orders through an online account, which changes how the order is raised but not why it matters. The options are covered in ordering materials through supplier portals.
Store the matched set together. The order, the docket and the invoice belong in one place, filed against the job code. A bookkeeper who has all three can allocate the cost in minutes and can answer a client’s question about a single line without ringing around the site. If a docket is missing, that gap is worth chasing on the day, while the driver’s name and the time of the drop are still fresh in somebody’s memory.
Worked example: a small builder in western Sydney
Consider a builder in western Sydney who runs a handful of jobs at the same time, with a site supervisor looking after most of them and the owner on the rest. Before the habit was introduced, the supervisor ordered by phone, the owner paid the monthly statements, and the cost on the job with the most change orders could not be explained when the client asked for a final account. Nobody had been dishonest. The orders were made without a job code, deliveries were signed for without a check, and the invoices arrived with descriptions that matched no particular job.
The fix was modest. Each job received a short code, and the supervisor raised an order from a simple template for anything above the agreed threshold, writing the job code on every docket that came back. Deliveries were checked on arrival, and the docket was filed with the order in the job folder. Within a few weeks the owner could see which items were running over, and could answer the client with the cost, the variation it belonged to and the price that had been agreed. The habit did not make the work any quicker. It made the money traceable, and that was what the client had actually asked about.
Notice what did not change. The builder did not buy a new system and did not hire an administrator. The steps were the ones any small business can follow with a template, a folder and a clear rule about the threshold. The discipline carries the value, and the discipline is easiest to keep when the template is short enough to fill in on a site.
Protecting supplier and job data
A purchase order file holds more than prices. It often carries a contact name, a mobile number, a delivery address and sometimes a bank detail for a supplier or subcontractor. That is personal and commercial information, and it needs the same care as the rest of the business records. Keep the purchase order folder in a shared drive with restricted access, use a strong and unique password on the account that holds it, and do not send bank details in a plain email. If a supplier asks you to change their bank details, confirm the change by ringing a number you already hold, not the number in the new message.
Two official resources are worth reading against your own set-up. The Australian Signals Directorate publishes small business cyber security guidance through its small business hub, and that is the place to start on basic account security. The Office of the Australian Information Commissioner publishes privacy guidance for organisations, including a page for small business, which sets out how personal information should be handled. Read the current pages rather than a summary of them, because the advice is updated and a purchase order system is only as safe as the account that opens it.
Reviewing the habit each month
Once a month, pull a sample of orders and check them against the invoices and the job costs. Look for orders with no job code, deliveries with no docket filed, invoices with no order behind them and approvals that were given only verbally. Each gap shows where the habit has slipped. It is rarely carelessness. It is usually a step that is too hard to follow on a busy day, and the fix is to make that step easier, not to add another rule that nobody reads.
The review also feeds the wider business. A price that keeps moving on the same item is a reason to talk to the supplier about the account terms. Regular overruns on one type of job say something about the estimate, and the estimate is where the margin is protected. The same discipline helps when the owner has to show the records behind their licence obligations. The PointCPD guide to how NSW builder CPD works sets out the broader picture, and a purchase order habit is one of the small systems that make that picture easier to evidence.
If you take only one thing from this, make it the job code on every order. It costs nothing to set up, it is free to keep, and it is the link that lets every other document in the file answer a client’s question.
Questions builders ask
Do I still need purchase orders if I already have a credit account with my merchant?
Yes. The account sets the terms on which you can buy and pay, but it does not record which job a load is for or what price you accepted for that delivery. The order does both, and it is the document you check the invoice against when it arrives.
What should a purchase order for a small builder include?
It needs the supplier, the job code, the delivery address and the date the materials are needed by. Each item should be described in words the supplier will recognise, with the agreed quantity and unit price, the name of the person who raised it, and who may receive it on site.
How do I stop site staff ordering on the phone without a job code?
Make the template easy to use from a phone, put the threshold for a mandatory order on the site box, and make the job code the first thing the template asks for. Review a sample each month, because most slips come from a step that is too awkward rather than from carelessness.
What should I do when a delivery does not match the order?
Note the difference on the docket before anyone signs, photograph any damage while the load is still there, and tell the supplier the same day. Keep the marked docket with the order and the invoice, so the difference is corrected on the account rather than argued at the final account.
Should I email purchase orders, and how should bank details be handled?
Purchase orders can be sent electronically, but bank details should never travel in a plain email. If a supplier or subcontractor changes their bank details, confirm the change by calling a number you already hold, not the number in the new message.
Will a purchase order protect me if a client disputes the cost of extra materials?
It helps only when the order refers to an agreed variation. An order raised without the client agreeing to the change shows what you spent, not what the client agreed to pay. Check the contract for how variations must be documented before you buy the extra items.
Sources
- Small business cyber security · Australian Signals Directorate
- Privacy for small business · Office of the Australian Information Commissioner
Published 26 October 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.
