Introduction
Most construction businesses have a purchase order process that looks good on paper but fails in practice.
The policy says all orders require a PO before materials are ordered. Reality is, half the materials arrive on site with no PO raised. Site teams call suppliers direct because the formal process is too slow or complicated.
When I joined Milestone, this was exactly our situation. We had a PO policy. Nobody followed it because raising a purchase order required filling out forms, getting multiple signatures, and waiting 48 hours for approval. Meanwhile, work had to keep moving.
So people worked around the process. Ordered materials, dealt with the paperwork later. Or never.
The result was invoice chaos. Accounts receiving invoices for materials nobody remembered ordering. No agreed prices to check against. Delivery disputes with no documentation. Payment delays because we couldn't verify what we were supposed to pay.
We rebuilt the PO process from scratch. Made it faster to raise a PO than to skip it. Within three months, PO compliance went from 50% to 98%. Invoice disputes dropped by 90%. Time to process invoices fell from 30 minutes to under 3 minutes.
This guide shows you exactly how to create a purchase order process that people will actually use.
Why Purchase Orders Matter in Construction
Purchase orders do three critical things:
1. Lock In Pricing Before You Commit
A PO documents the agreed price before materials are ordered. When the invoice arrives, you have proof of what was agreed. No arguments, no surprises.
Without a PO, you're trusting suppliers to invoice at the rate you think you agreed. Sometimes they do. Often they don't.
2. Create an Audit Trail
POs show who ordered what, when, for which project, at what cost. Essential for budget tracking, cost control, and financial audits.
Without POs, you're piecing together what was ordered from invoices that arrive weeks later. Impossible to track commitments or manage budgets in real time.
3. Enable Three Way Matching
Three way matching compares the purchase order, delivery note, and invoice before payment. This catches invoice errors, prevents duplicate payments, and resolves disputes.
Without POs, you can't do three way matching properly. You're paying invoices based on trust, not verification.
The Problem With Traditional PO Processes
Most construction PO processes fail for the same reasons:
Too Slow
Raising a PO requires logging into a system, filling out forms, attaching quotes, getting approvals from multiple people. Takes 20 to 30 minutes.
By the time the PO is approved, the materials should already be on site.
Too Complicated
Different forms for different order types. Special approval routes for different project values. Exceptions and workarounds documented in policies nobody reads.
Site teams don't have time to navigate bureaucracy. They need materials tomorrow.
Not Mobile Friendly
PO systems designed for office use. Require desktop access, VPN connections, multiple logins.
Site managers are not sitting at desks. If they can't raise a PO from their phone in under 2 minutes, they won't do it.
No Flexibility for Urgent Orders
Every order follows the same approval process regardless of urgency. Emergency cement delivery for tomorrow requires the same three approvals as routine fixings ordered two weeks in advance.
When the process treats everything the same, people work around it for urgent orders. Then they work around it for everything.
How to Build a Purchase Order Process That Works
Step 1: Make PO Creation Fast and Mobile
Speed is everything. If raising a PO takes longer than calling the supplier and ordering verbally, people will skip the PO.
Target: 2 minutes from opening the app to PO submitted for approval.
How to achieve this:
- Mobile first design. App based, not desktop software
- Pre populated supplier lists with contact details
- Product catalogues for common materials (search, not typing)
- Photo upload for quotes (not manual data entry)
- Autofill project codes and cost centres based on user defaults
- One screen, minimal fields, smart defaults
I can raise a PO on my phone while standing on site in under 90 seconds. Select supplier, add items, choose project, submit. If you're taking 10 minutes, your system is the problem.
Step 2: Implement Tiered Approval Workflows
Not every purchase order needs the same approval process.
£200 of fixings should not require the same approval chain as £20,000 of structural steel.
Approval tiers that work:
| Order Value | Approval Required | Target Response Time |
|---|---|---|
| Under £500 | Auto approve or team lead | Instant or 1 hour |
| £500 to £2,500 | Project manager | 4 hours |
| £2,500 to £10,000 | Commercial manager | Same day |
| Over £10,000 | Director level | 24 hours |
Adjust thresholds based on your business size. The principle is the same: low value orders get approved fast, high value orders get proper scrutiny.
Step 3: Enable Mobile Approvals
Approvers are not sitting at desks waiting to approve purchase orders.
They're on site, in meetings, travelling between projects. If they need to log into a desktop system to approve, your POs sit in a queue for days.
Mobile approval must include:
- Push notifications when PO awaits approval
- Full PO details visible on phone (supplier, items, prices, project)
- Ability to approve or reject with one tap
- Comments field for rejection reasons
- Attachment view for quotes and supporting documents
When approvers can approve from their phone in 30 seconds, approval times drop from days to hours.
Step 4: Create Supplier Catalogues
Typing out item descriptions and prices every time you order cement from the same supplier is wasted time.
Build catalogues for your regular suppliers with common products, descriptions, and agreed rates pre loaded.
Benefits:
- Faster PO creation (search and select, not type and price)
- Consistent pricing (agreed rates locked in, not renegotiated every order)
- Accurate product descriptions (no typos or variations)
- Easier invoice matching (standardised items match cleanly)
Start with your top 10 suppliers by spend. Document their common products and agreed rates. Expand from there.
Step 5: Integrate With Budget Tracking
Purchase orders should commit budget the moment they're approved, not when invoices arrive weeks later.
This requires your PO system to integrate with project budgets.
How this works:
- PO gets approved for £5,000 of materials
- System commits £5,000 against project budget immediately
- Available budget reduces by £5,000 in real time
- Project manager can see updated budget before placing next order
This prevents budget overruns that only get discovered when all the invoices arrive at month end.
Spreadsheet based budget tracking can't do this. You need real time integration between procurement and financial systems.
Step 6: Link Purchase Orders to Delivery Confirmation
When materials arrive on site, the delivery confirmation should link directly to the original purchase order.
Digital delivery confirmation workflow:
- Materials arrive on site
- Site operative opens app, scans or selects the PO
- Confirms quantities received, flags any shortages or damage
- Takes photos if needed
- Digitally signs confirmation
- Record created and linked to PO instantly
No lost delivery notes. No chasing site teams for paperwork. No gaps in the audit trail.
This delivery confirmation feeds into three way matching when the invoice arrives.
Step 7: Make Exceptions Visible, Not Blocked
Sometimes you need to order without a full PO. Emergency breakdown. Design change. Client variation.
Don't make exceptions impossible. That forces people to lie or work around the system.
Make exceptions visible instead.
Exception handling that works:
- Allow retrospective POs with a flag showing they were raised after order
- Require justification comment (why was this ordered without a PO)
- Route retrospective POs for additional approval
- Report on exception rates monthly
- Investigate teams with high exception rates
Target: under 5% of orders should be exceptions. If it's higher, your standard process is too slow or complicated.
Common Purchase Order Process Mistakes
Mistake 1: Requiring POs for Everything
Some items don't need formal POs. Coffee for the site office. £15 of emergency fixings from the local merchant. Taxi fare.
Setting a minimum threshold (e.g. £100 or £200) for formal POs reduces admin without losing control.
Petty cash or purchase cards handle small purchases. POs cover everything above the threshold.
Mistake 2: Too Many Mandatory Fields
Every field you make mandatory adds time to PO creation.
If "delivery instructions" and "special requirements" and "contact person" and "alternative delivery address" are all mandatory, people spend 10 minutes filling out forms that are blank 90% of the time.
Make only essential fields mandatory. Everything else optional.
Mistake 3: No Supplier Master Data
If users have to type in supplier details every time they raise a PO, you'll have ten different versions of the same supplier name. "ABC Supplies", "ABC Supplies Ltd", "ABC Supply", "A.B.C. Supplies".
When invoices arrive, matching fails because the supplier name on the invoice doesn't exactly match the PO.
Create a supplier master list. Users select suppliers from the list, not freeform typing. Supplier details (address, payment terms, contact) pre populate.
Mistake 4: Ignoring PO Compliance Metrics
If you're not tracking how many orders have POs versus how many don't, you have no idea if the process is working.
Track these metrics:
- PO compliance rate (percentage of orders with POs raised before delivery)
- Average time to raise a PO
- Average time to approve a PO
- Exception rate (retrospective POs)
- PO to invoice matching accuracy
Review monthly. Investigate why compliance is low or approval times are slow. Fix the process, not the people.
Practical Implementation Steps
Week 1: Map Current Process
Document how purchase orders actually work today, not how the policy says they should work.
Interview site managers, project managers, procurement team, accounts. Understand where the process breaks down and why people work around it.
Week 2: Define New Process
Design the process around speed and simplicity. Mobile first, tiered approvals, minimal mandatory fields, exception handling.
Set clear targets: 2 minutes to raise a PO, 4 hours for approval, 95% compliance.
Week 3: Configure Systems
Set up your procurement software with supplier lists, product catalogues, approval workflows, budget integration.
If your current system can't deliver fast mobile PO creation and approvals, you need different software.
Week 4: Pilot With One Team
Roll out to one project team or division. Test the process in real conditions. Gather feedback. Fix friction points.
Measure compliance, speed, approval times. Prove the new process is faster and easier than the old one.
Weeks 5-8: Full Rollout
Roll out to remaining teams. Train everyone on the new process and system.
Enforce the no PO, no order rule once you've proven the process is fast enough to comply with.
Monitor compliance weekly. Chase exceptions. Celebrate teams with high compliance.
Conclusion
An effective construction purchase order process is fast, mobile, and tiered.
Fast enough that raising a PO takes 2 minutes, not 20. Mobile so site teams can do it from their phones without returning to the office. Tiered so low value orders get approved instantly and high value orders get proper scrutiny.
The construction businesses with tight procurement control haven't achieved it through stricter policies or more enforcement. They've built processes that are easier to follow than to work around.
If your PO compliance is under 80%, your process is failing. Don't blame the site teams. Fix the friction.
Digital PO creation, mobile approvals, supplier catalogues, budget integration, delivery confirmation. These aren't nice to have features. They're requirements for a purchase order process that actually works.
Get Your PO Process Right
We built StoneRise to make purchase orders effortless. Mobile PO creation in under 2 minutes, instant approvals from phones, supplier catalogues with agreed rates, real time budget integration, digital delivery confirmation linked to POs.
Our customers achieve 98% PO compliance and cut procurement admin time by 75%.
If you want a purchase order process people will actually follow, request a demo.
FAQ: Construction Purchase Order Process
What is a purchase order in construction?
A purchase order is a formal document from the buyer to the supplier confirming what materials or services are being ordered, at what quantities, prices, and delivery dates. It creates a legally binding agreement and provides the audit trail needed for three way matching and invoice verification.
How long should it take to raise a purchase order?
Target 2 minutes from opening the system to PO submitted for approval. Modern mobile procurement systems achieve this through supplier catalogues, pre populated fields, and smart defaults. If your process takes 20 to 30 minutes, that's why people skip it.
Who should approve purchase orders?
Use tiered approvals based on order value. Low value orders (under £500) can auto approve or require team lead sign off. Medium orders (£500 to £10,000) need project or commercial manager approval. High value orders (over £10,000) require director level approval. This balances speed with financial control.
What should be included in a construction purchase order?
Essential fields: supplier details, delivery address, items ordered with descriptions and quantities, unit prices, total price, delivery date, project code, cost centre. Optional fields: delivery instructions, special requirements, payment terms. Don't make fields mandatory if they're blank 90% of the time.
How do you enforce purchase order compliance?
Make it faster to raise a PO than to skip it. Mobile creation in under 2 minutes, fast approvals, minimal fields, exception handling for genuine emergencies. Track compliance rates and investigate why teams aren't using the process. Fix the friction, don't just demand compliance.
Last updated: February 2026
