A practical completion certificate records the date the works were finished enough to use, attaches the list of small items still to do, and starts the clocks that follow: the defects period, the first retention release and the end of delay charges. AI can draft one from your contract's own wording, provided you check every term against the contract.
The certificate does not say the job is perfect, and your contract, not a template, defines practical completion. Two things cause trouble at handover: a date written on the wrong day, and a snag list that mixes five-minute touch-ups with work that stops the customer using the room. The clauses come first below, because an AI draft is only as good as your understanding of what it is drafting.
Five things the certificate sets in motion
Contracts differ, so read this as the usual pattern in standard-form building contracts, not a promise about yours. The point of listing it is to show why one line on one page matters.
| What it triggers | In plain terms | Where it bites on a small job |
|---|---|---|
| The completion date | The day the works counted as complete for contract purposes | Everything below is counted from this date |
| The defects period starts | A set time in which the contractor returns to fix defects that show up | Often six to twelve months; yours is whatever the contract says |
| First retention release | Money held back from payments is partly released, commonly half at this point | The cash arrives when you invoice for it, not automatically |
| Possession and care | The customer takes over the finished work for use | Who insures and secures the building from this date should be written down; ask your broker before handover |
| Delay charges stop | Late-completion charges, called liquidated damages in many contracts, no longer build up | A date later than the real finish can keep charges running; a date earlier than the real finish can leave the customer with an unusable room and a defects clock already ticking |
Practical completion has no single definition. Standard forms describe it in their own words, some call it substantial completion, and in disputes trifling outstanding items have been treated as not blocking it, though whether an item is trifling depends on the facts. Visible defects, other than trifling ones that go on the schedule, should be put right before the certificate is issued, because the defects period is not a chance to correct problems everyone could already see. Hidden defects nobody can find yet are different: they are what the defects period is for.
The certificate clause by clause
The contract it belongs to
The opening lines name the parties, the site and the contract by title and date, and say which variations are included. This stops the certificate being mistaken for one that belongs to a different job, and it ties the completion date to the right document. The slip to avoid is quoting the original quote when two variations later changed the scope. List variations by number and date, and see how small builders price variations and change orders if yours are loosely recorded.
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Buy nowThe statement that the works are practically complete
One sentence says the works reached practical completion, as the contract defines it, on a stated date. The words that matter are "as defined in clause X of the contract". Your contract's definition decides what qualifies, and it is often along the lines of complete except for minor items that do not stop the customer using the works. Do not paraphrase it in the certificate; refer to the clause. Whoever certifies is whoever the contract names, which on larger jobs is an architect or surveyor. On a small job with nobody named, it is usually the customer and the contractor together.
The date
The date is a statement of fact about when the works reached the contract's standard. It is not the day you sign or the day the customer pays. If the certificate is signed on the 20th for works that reached the standard on the 14th, write the 14th as the completion date and the 20th as the signing date. Backdating to speed up retention release, or postdating to avoid an argument, both create more trouble than they remove.
The schedule of outstanding items
Snags go on an attached schedule: the item, where it is, who fixes it and by when. Two kinds of item usually appear: finishing touches that do not stop use, such as a paint touch-up or a silicone gap, and small items waiting on parts or a return visit. The schedule is what stops "I thought you were fixing that" later, so every line needs a date. Some contracts let the customer hold back money for outstanding items; the amount and the rule come from the contract, not from an AI. Anything that stops the customer using a room does not belong on the list at all, because it means the job is not at practical completion yet. The snagging report tutorial covers how to order and caption the items.
The defects period
This clause needs a start date, a length, an end date and a way to report a defect: in writing, to whom, ideally with photos. Work out the end date and write it out in full rather than leaving "six months" to be recalculated later. Say what is not covered, which is usually wear, misuse, lack of maintenance and work done by others. Some contracts call this the rectification period. If your contract has no defects period at all, the certificate cannot create one by itself. Agree the arrangement with the customer in writing before signing, and note it as an agreement.
Retention
State the percentage held, the amount in money, the part released now and the trigger for the rest. In many contracts the second half is released when a further certificate confirms the listed defects have been put right, and if the contractor does not come back, the customer may be allowed to use someone else and deduct the cost from the money held. Release is not automatic: raise the invoice or application the contract describes. Rules on retention vary and some places are moving to restrict it, so confirm what applies to your contract. Retention tracking with AI reminders helps you chase the release.
Handover items
List the keys and alarm codes, manuals, warranties and guarantees, test and commissioning certificates, and as-built drawings where relevant, with a "received by" line and a date for each. A missing safety certificate is a reason to hold the certificate back, not a line to push onto the snag list. The handover pack checklist shows how to gather the paperwork before the walk-round.
What the certificate does not waive
A short sentence saying that issuing the certificate does not waive the customer's rights about defects or the outstanding items protects the customer from signing away claims. The contractor should want it too, because it shows the certificate is a record, not a settlement. Watch for AI-added wording such as "full and final settlement" or "the Contractor is released from all liability". Neither belongs on a certificate.
Signatures
Names, roles and dates for whoever the contract says certifies, plus the other party's acknowledgement, and a copy for each side. On a small job the customer and contractor usually sign together during the handover walk-round, which is also the best moment to agree the snag list.
Seven questions your contract answers before the AI starts
Answer these from the contract itself, writing the clause number beside each answer. They become the facts and the pasted wording in the prompt later.
- How does the contract define practical completion? Copy the sentence exactly.
- Who certifies it, and how is the other side told?
- How long is the defects period, and when does it start?
- What percentage is held as retention, and does it release in two stages or one?
- Are there delay charges, and when do they stop?
- Who insures and secures the works after completion?
- How must notices be sent: email, letter or text?
Where the contract is silent, write "not covered" beside the question, and make sure the AI is told not to fill the gap. Where two answers seem to conflict, ask a lawyer before the certificate is signed. If the job ran on a quote and a few lines of terms, the certificate will be short, and the missing answers are a prompt to fix your contract template for the next job. The small-job construction contract tutorial is a good place to start that.
A kitchen extension, filled in
A small firm has finished a single-storey kitchen extension. These are the facts it has gathered from the contract and the job file. All the figures are illustrative.
| Item | Entry |
|---|---|
| Contract sum, including two variations | $62,000 |
| Retention held | 5% of the contract sum, $3,100 |
| Date the works reached practical completion | 14 May |
| Defects period | Six months, 14 May to 14 November |
| Released on the certificate | Half of the retention, $1,550 |
| Second release | The other $1,550, when the contract's closing certificate is issued after the defects period |
| Outstanding items | Eight: six to finish by 28 May, two waiting on a delivery due 2 June |
| Handover items | Two sets of keys, electrical test certificate, appliance guarantees, hob manual |
One caution on the money. In many contracts retention is a percentage of certified payments, so the figure at the moment of release can differ slightly from a flat 5% of the contract sum. Work the sums out yourself from the contract and give the AI the finished figures. A certificate should never contain arithmetic that a chat assistant did.
The timeline that follows from those facts is short.
| Date | What happens | Money |
|---|---|---|
| 14 May | Walk-round, certificate signed, snag schedule attached | Invoice raised for the $1,550 first release |
| 28 May | Six items finished and ticked off with the customer | None |
| 2 to 5 June | Delivery arrives, two items fitted | None |
| Before 14 November | Defects reported in writing during the period are fixed | None |
| After 14 November | Closing certificate issued once the listed defects are put right | Invoice for the second $1,550 |
Prompting the draft, then checking it
The prompt does three jobs: it fences the AI inside your facts and your pasted contract wording, it makes gaps visible instead of silently filled, and it asks for a list of everything the AI added on its own.
Draft a one-page Certificate of Practical Completion for a small building job.
Rules
1. Use only the facts and contract wording pasted below. Do not add any term, period, percentage, deadline or legal wording that is not in the paste.
2. Where something is missing, write [MISSING: what is needed] and do not guess.
3. Keep my defined terms exactly as written ("the Works", "the Client", "the Contractor").
4. Layout: 1 Contract; 2 Practical completion and date; 3 Outstanding items (refer to Schedule 1); 4 Defects period with start and end dates; 5 Retention; 6 Handover items; 7 Notes; 8 Signatures.
5. After the certificate, list every assumption you made and every sentence that does not come from my paste.
FACTS
Parties: [Client name] (the Client) and [Contractor name] (the Contractor)
Contract: agreement dated [date], single-storey kitchen extension at [site address] (the Works), two variations agreed in writing
Contract sum including variations: $62,000
Practical completion reached: 14 May
Defects period: six months from the date of practical completion
Retention held: $3,100 (5% of the contract sum). Released on this certificate: $1,550
Outstanding items: Schedule 1, eight items, six to finish by 28 May, two waiting on a delivery due 2 June
Handover: two sets of keys, electrical test certificate, appliance guarantees, hob manual
CONTRACT WORDING (paste the clauses, not the whole contract)
[clause defining practical completion]
[clause on the defects period]
[clause on retention and its release]An illustrative draft, showing the gaps the rules should make visible:
Certificate of Practical Completion
1. Contract. This certificate relates to the agreement dated [date] between [Client name] (the Client) and [Contractor name] (the Contractor) for a single-storey kitchen extension at [site address] (the Works), including the two variations agreed in writing. Contract sum including variations: $62,000.
2. Practical completion. The Works reached practical completion on 14 May, as described in [MISSING: clause number of the contract's definition].
3. Outstanding items. The items in Schedule 1 are outstanding. The Contractor will complete the six items due on 28 May by that date, and the two items waiting on a delivery due on 2 June [MISSING: the agreed completion date for these two].
4. Defects period. The defects period runs for six months, from 14 May to 14 November, under [MISSING: clause number]. [MISSING: how the Client reports a defect, and the Contractor's response time.]
5. Retention. Retention of $3,100 (5% of the contract sum) is held under the contract. $1,550 is released on this certificate. The remainder is released as the contract provides [MISSING: the contract's trigger for the second release].
6. Handover. Two sets of keys, the electrical test certificate, the appliance guarantees and the hob manual have been handed over.
7. Signed by the Client ........ Date ........ Signed for the Contractor ........ Date ........
Now read it the way the customer's adviser would. Every [MISSING] is a question you can answer from the contract in a minute, which is the whole point of the fence. Check each sentence against the paste, and scan a first draft for these common slips:
- A defects period that is not yours. Twelve months appears in many templates, so an unfenced draft may offer it even when your contract says six.
- Wording that settles the argument. "Full and final settlement" and "released from all liability" do not belong on a certificate.
- A deadline you never gave. Something like "retention released within 14 days" reads naturally and may contradict the contract.
- Changed defined terms. "Employer" for "Client", or "Defects Liability Period" for whatever your contract calls it.
- Clauses from another contract. A witness block, or a delay-charges paragraph when your contract has no such charges.
- The wrong date. The date the AI was asked is not the completion date.
A second prompt is a cheap safety net: "List every number and date in this certificate with the line of my paste it came from." Anything with no source gets fixed or deleted. Keep customer names and the site address as placeholders in the chat and type them in afterwards.
The snag list as a schedule
Schedule 1 is what the customer will hold you to, so it earns real care. This is the kitchen extension's, with the two classes the walk-round produced. Nothing on it stops the family using the kitchen. If the sink had not worked, the job would not be at practical completion.
| No. | Where | Item | Fix by | Who |
|---|---|---|---|---|
| 1 | Utility room | Paint touch-up above the window | 28 May | Contractor |
| 2 | Kitchen | Bi-fold door catches at the bottom edge; adjust | 28 May | Contractor |
| 3 | Kitchen | Chipped cover plate on the island socket; replace | 28 May | Electrician |
| 4 | Kitchen | Silicone gap behind the sink | 28 May | Contractor |
| 5 | Hall | Gap at the skirting-board corner | 28 May | Contractor |
| 6 | Kitchen | Extractor hums at full speed; check the mounting | 28 May | Contractor |
| 7 | Kitchen | Worktop end cap, waiting for delivery | Delivery 2 June, fit by 5 June | Contractor |
| 8 | Kitchen | Splashback tile replaced after a chip, waiting for delivery | Delivery 2 June, fit by 5 June | Contractor |
Take photos of items 7 and 8 on the day, so nobody argues later about whether the chip was there at handover. If your snag list starts as a pile of site photos, this tutorial on drafting a snagging list from photos shows the AI step, and the same rule applies: a person confirms each line.
Signs the job is not at practical completion yet
Pressure to sign comes from both sides: the contractor wants the retention, the customer wants the keys. These are reasons to wait.
- A required safety or test certificate has not been issued, for electrics, gas or anything else the work involved.
- A room, bathroom or kitchen cannot be used, or cannot be used safely.
- Heating or hot water has not been commissioned.
- An inspection sign-off that the work needs has not been given.
- Waste, scaffolding or open trenches are still a hazard on site.
- The customer has not been shown the main shut-offs for power, water and gas.
If the customer wants to move in before the job is ready, write it down: what is still unfinished, that they have agreed to occupy anyway, and who looks after what in the meantime. That note protects both of you and keeps the certificate honest.
Phased handovers and one-room-at-a-time jobs
Some jobs hand over in stages: the bathroom first, the rest weeks later. Contracts that plan for this define sections, each with its own completion date, so each section gets its own certificate and its own defects period. That is different from the customer simply moving in early, which some contracts treat as partial possession. Check which your contract provides. If it provides neither, record any early use in writing and keep a master list that shows which snags belong to which room.
Four slips that start the arguments
| Slip | How it shows up | Fix |
|---|---|---|
| Certificate dated at final payment | The defects period seems to start weeks late, and a warranty argument follows | Date it the day the works truly finished; keep the signing date separate |
| Snags agreed by word of mouth | "You promised to fix the gate", with no record | Everything on Schedule 1, each with a date |
| Template wording that differs from the contract | The certificate says twelve months and the contract says six | Fence the AI inside pasted contract wording, then check every term |
| Keys handed over, nothing signed | The family lives there, nobody agrees the completion date, and the retention release is disputed | Sign at the walk-round, or record the agreed date in writing the same day |
Once the certificate is signed, put the end of the defects period in your diary with a reminder four weeks earlier, so you can ask the customer for a final list before the deadline rather than after it.
Questions builders ask before signing off a job
Who signs a practical completion certificate when there is no architect?
Usually the customer and the contractor, together at the handover walk-round, unless the contract names someone else to certify. The contract decides, so check it first. If it names nobody, agree in writing who signs and what counts as complete, and keep one signed copy each.
Is practical completion the same as substantial completion?
They do the same job under different contract forms, so the label depends on your paperwork. Both mark the point when the works can be used with only minor items left. Use the term your contract uses and do not mix the two in one document, because each form attaches its own consequences to its own words.
Can the customer refuse to sign?
If the works have not reached the contract's standard, yes. Ask which items they say are outstanding, agree which of them stop use, fix those and reissue. If you think the refusal is unreasonable, follow the contract's dispute steps and ask a lawyer before acting. Your own certificate is not the end of the argument.
Do I need a lawyer to check the AI draft?
For a standard job on your usual contract, checking every term of the draft against that contract is the basic step. Ask a lawyer when the contract is bespoke, the sums are large, delay charges apply or the customer disputes the date. Having a lawyer review your certificate template once is usually cheaper than a dispute over a badly worded one.
Further reads
- Writing Client Updates and Snag Lists With AI for Builders — Client updates and snag lists for builders, written with AI
- AI for a Painting Business: Snag Lists and Final Walkthrough Sign-Off — A final walkthrough and sign-off routine from another trade
- AI in the Construction Field: Photos, Voice Notes and Punch Lists — Photos, voice notes and punch lists captured on site
- AI in Home Building: Buyer Enquiries, Warranty Calls and Handovers — Warranty calls and handovers after a build
- Can ChatGPT Draft a Subcontractor Agreement? Clauses to Check — The same check-every-clause habit applied to subcontract terms
- Can AI Draft a Remodelling Contract Template in Plain English? — Plain-English contract drafting for remodelling work
- Construction Cash Flow Forecast: Build One in a Spreadsheet With AI — Plan the cash that each retention release brings in
- ChatGPT for Contractors: Five Customer Messages to Draft and Check — Customer messages for contractors, drafted and then checked
- Bathroom Renovation Scope of Work: Draft Room-by-Room Lines With AI — How to turn site notes into numbered scope lines for each bathroom, with exclusions, allowances and client-supplied item rules that prevent disputes.
- Construction Final Account: Variations, Deductions and Sign-Off With AI — A worked small-job final account with variations, deductions and retention, plus an AI-drafted cover letter and the client sign-off checklist.
- Electrical Installation Certificate: What AI Can Draft and You Must Sign — Which boxes on an electrical installation certificate AI can draft, which the electrician must measure and sign, shown on a worked consumer unit job.
- Gutter Cleaning Invoices With Photo Proof and AI Job Summaries — A shot list, a voice-note-to-summary prompt, invoice wording and a dispute log: photo proof for gutter jobs that settles complaints early.
- AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.
Sources: plain-language construction reference entries on practical completion and the defects liability period. The retention percentage and period lengths in the examples are illustrations, not standards.