Materials and procurement

How to manage construction purchase orders

Issue a numbered purchase order for every material and rental buy, tie it to a job and cost code, record it as a committed cost the day it is issued, approve it within set dollar limits, update it in writing when anything changes, and pay only after matching the invoice to the PO and the delivery receipt.

Two construction professionals review paper plans beside a tablet at a jobsite workbench.
Plan reviews connect field conditions, drawings, and the next decisions on a job. AI-generated illustration.

To manage construction purchase orders, make one rule and enforce it: no buy without a PO number. Every purchase order should name the job, cost code, items, quantities, prices, delivery date and location, and your terms. Record it as a committed cost the day it is issued so the job cost report shows money already spoken for. Set approval limits by role, change POs in writing, and pay invoices only after matching them to the PO and the delivery ticket. That last step, the three-way match, is where most savings show up.

Contractors without a PO system usually find out what a job cost after the invoices land, which is too late to change anything. A PO system moves that knowledge to the day of the order.

What every construction purchase order should include

Construction PO fields
FieldWhy
PO numberUnique reference the supplier puts on every ticket and invoice
Job number and cost codeCharges cost to the right place in job costing
Supplier, contact, quote referenceLinks back to the price you agreed
Items, specs, quantities, unit pricesWhat you are buying and at what price
Freight, tax, and other chargesNo surprises on the invoice
Delivery date, address, and site contactWhat the supplier commits to
Terms and conditionsPayment terms, returns, warranty, backcharges
Approver and dateWho authorized the spend

How to set up a PO process step by step

1. Decide what needs a PO

The simplest rule is every material purchase and every equipment rental. Some companies let field staff use a company card for small counter buys under a set dollar amount, coded to the job the same day. Write the rule down and tell suppliers you will not pay invoices without a PO number.

2. Set approval limits

Give each role a dollar limit. For example, a foreman might approve small stock orders, a PM approves up to the remaining budget for that cost code, and anything over budget or above a higher amount goes to operations or the owner. The limits should fit your company; the point is that big commitments get a second look before they are made.

3. Number POs and tie them to the budget

Use a numbering scheme that includes the job, such as job number plus sequence. When the PO is entered, the system or spreadsheet should show the cost code budget, what is already committed, and what is left. A PO that pushes a code over budget is an early warning, not something to discover at month-end.

4. Send your terms with the PO

Suppliers often send their own quote and acknowledgment forms with different terms. Under the Uniform Commercial Code (UCC) section 2-207, a contract can still form when the forms do not match, and between merchants the additional terms in an acceptance can become part of the deal unless the offer limits acceptance to its own terms, the new terms materially alter it, or you object. That is one reason to put your terms on the PO and read supplier acknowledgments rather than filing them.

The UCC also generally requires a signed writing for a sale of goods priced at $500 or more to be enforceable (section 2-201), and between merchants a written confirmation can satisfy that unless the recipient objects in writing within 10 days of receiving it. States adopt their own versions, so treat these as general rules and ask counsel about specific disputes.

5. Change POs in writing

Quantities change, dates move, prices get revised. Each change should be a numbered revision to the PO, not a phone call. Update the committed cost at the same time. If the change comes from an owner change, note the change order number so the cost can be billed.

6. Receive against the PO

On delivery, the receiver checks the load against the PO, notes shortages or damage on the ticket, and sends the ticket to the office. Partial deliveries are recorded as partial so the PO stays open for the balance.

7. Three-way match before paying

Accounts payable compares the invoice with the PO (price and terms) and the delivery receipt (quantity). Matches get paid. Mismatches go back to the PM or the supplier. This is where price creep, duplicate invoices, and charges for undelivered material get caught.

8. Close POs at the end of the job

Open POs inflate committed costs and make cost to complete look worse than it is. At closeout, review every open PO: close the ones that are complete, cancel unneeded balances in writing, and confirm returns and credits.

Worked example: a plumbing contractor's PO log

Here is an illustration. A plumbing contractor's PM on a $640,000 school renovation issues PO 2417-008 for $38,600 of cast iron pipe and fittings against a cost code budgeted at $41,000. The PO is entered as a committed cost the same day, leaving $2,400 in the code.

The supplier delivers in two loads. The first ticket shows full quantity on pipe but six fittings short; the foreman notes it and sends a photo. The invoice for the first load arrives at the full PO amount for that load. Accounts payable matches it to the ticket, sees the shortage, and holds payment on those items until the backorder arrives. When the final invoice comes in at a higher unit price on one fitting than the PO, AP sends it back. The supplier issues a corrected invoice. Without the PO and the ticket, both errors would likely have been paid.

Purchase orders on residential and small jobs

Small remodelers and service contractors sometimes skip POs because orders are small and frequent. A lighter version still works: a PO number from a simple numbered list, the job name, and the supplier quote attached, entered by the person ordering on a phone. Many suppliers let you put a job name or PO number on account purchases, which makes coding invoices much easier at month-end. The goal is the same as on a commercial job: know what you committed, check what you were billed, and keep material costs inside each job's estimate.

Mistakes to avoid

  • Issuing POs after the order. A PO written to match an invoice controls nothing.
  • No cost code on the PO. Costs get dumped into general material and job costing loses its value.
  • Never closing POs. Old balances distort committed costs and forecasts.
  • Paying without a receipt. Pay for what arrived, not what was ordered.
  • Ignoring supplier terms. Their acknowledgment may say something different from your PO. Read it.
  • Approval limits nobody follows. If everyone can approve anything, the limits are decoration.

Templates and tools that help

A job cost report template shows committed costs next to actuals, and a material delivery log template links each delivery to its PO. See also how to track committed costs before invoices arrive and how to manage construction procurement.

Smart Business Automator ties purchase commitments to job cost codes and can pull data from supplier invoices, so mismatches stand out before payment. See job costing and WIP automation.

Frequently asked questions

Do small contractors really need purchase orders?

Yes, even a simple numbered PO in a spreadsheet helps. It records the agreed price and quantity, gives you committed costs for job costing, and lets you check invoices before paying.

What is a three-way match?

Comparing the supplier invoice with the purchase order and the delivery receipt before paying. It confirms you are paying the agreed price for what actually arrived.

What is the difference between a purchase order and a subcontract?

A purchase order usually covers materials or equipment, while a subcontract covers labor or labor and materials to perform part of the work. Some contractors use a PO for material-only suppliers and a subcontract for installers.

What is a blanket purchase order?

A PO that covers repeat purchases of the same items over a period, often at agreed prices, with releases against it as material is needed.

Sources

  1. Cornell Law School LII: UCC 2-201, Formal requirements; statute of frauds
  2. Cornell Law School LII: UCC 2-207, Additional terms in acceptance or confirmation
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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