Key takeaways
- Reference the contract, purchase order and scope of work by number and revision.
- State the completion date explicitly — warranty and defect-liability periods run from it.
- Say whether this is practical (substantial) completion or final completion.
- Attach or reference the snag list and its status; a certificate issued "subject to snags" must list them.
- State the payment or retention consequence, and who signs on each side.
What the certificate must contain
| Field | Why it is needed | Risk if missing |
|---|---|---|
| Parties | Client, contractor or supplier, and consultant if any | Unclear who certified what |
| Project and contract reference | Contract or PO number and scope revision | Scope closed cannot be identified |
| Description of work completed | Summary against the deliverable numbering | Disagreement over what was accepted |
| Completion date | Starts warranty, defect liability and retention clocks | Warranty period unenforceable in practice |
| Type of completion | Practical or final completion | Final payment claimed too early |
| Snag / defect status | None, or listed with a rectification date | Defects treated as accepted work |
| Warranty and defect liability | Duration and what it covers | Open-ended liability assumed |
| Payment consequence | Final invoice or retention release trigger | Payment stalls without a trigger |
| Signatures and stamps | Authorised signatories on each side, dated | Certificate carries no weight |
Practical completion versus final completion
| Aspect | Practical completion | Final completion |
|---|---|---|
| Meaning | Work usable for its purpose, minor snags may remain | All snags rectified and obligations discharged |
| Typical effect | Handover, insurance transfer, part retention release | Balance of retention released, liability period ends |
| Attachments | Snag list with rectification dates | Snag closure evidence, as-built and warranty documents |
| Common error | Issued with an unlisted snag list | Issued before snags are verified closed |
Issue two certificates where the contract provides for both. Compressing them into one document is what leads to retention being released while defects are still open.
Handover: the documents that go with the certificate
- Snag list with status and rectification dates.
- As-built drawings or final deliverable files in the agreed format.
- Test and commissioning reports, or acceptance evidence for services.
- Warranty and guarantee certificates from suppliers and subcontractors.
- Operation and maintenance manuals, training records and spare-part lists where applicable.
- Final account summary showing approved variations.
Assemble the handover pack before requesting the certificate. Most completion delays are documentation delays, not construction or delivery delays.
After the certificate
Once completion is certified, issue the final invoice referencing the certificate number and the approved variations, and record the receipt when payment clears. Keep the certificate with the scope of work, the accepted progress reports and the approved timesheets — together they are the complete record of what was delivered and when.
How to issue a completion certificate
Step 1: Verify the scope
Check each numbered deliverable in the scope of work is delivered and accepted.
Step 2: Close the snags
Walk the works or review the deliverables, list snags and set rectification dates.
Step 3: Assemble the handover pack
Collect as-built documents, test reports, warranties and manuals.
Step 4: Choose the completion type
Decide whether this certifies practical or final completion and state it plainly.
Step 5: Draft the certificate
Include parties, contract reference, work completed, completion date, warranty and payment effect.
Step 6: Sign and act on it
Obtain signatures and stamps, then issue the final invoice referencing the certificate.
Frequently asked questions
Who issues a completion certificate?
Usually the client, the consultant or the engineer certifies completion of the contractor's work. On smaller engagements the supplier issues it and the client countersigns to acknowledge acceptance.
Is a completion certificate the same as a handover certificate?
They overlap. Completion certifies the work is complete on a stated date; handover records the transfer of the works, keys, documents and responsibility. Many projects use one document that does both explicitly.
Can a completion certificate be issued with outstanding snags?
Yes, at practical completion — provided the snags are listed with rectification dates and the certificate states that final completion follows their closure.
Does the completion certificate release retention?
Only to the extent the contract says. Typically part of the retention is released at practical completion and the balance after the defect-liability period ends, which is why the type of completion must be stated.