Site Diary: What It Is, What to Record and Why It's Kept
A site diary is the dated, daily record of what happened on a construction site: the work done and where, the labour and plant on site, the weather, instructions received, delays, deliveries, visitors and photographs. Written on the day by people who saw it, it's the evidence every later valuation, claim and dispute relies on.
Need the blank form? Get the free site diary template (Excel, or fill it in online and save it as a PDF). Want to see good entries first? Read annotated site diary examples.
What is a site diary?
On a UK construction site, the site diary is kept by whoever has eyes on the work. That's usually the site engineer, section engineer, foreman or site manager, and you'll also hear it called the daily diary or daily site record. Expect one entry per shift, or one per work area on bigger jobs. In the US the same document usually goes by daily log; here's how the UK and US terms map.
I'd describe it more bluntly. The site diary is the only project document written by someone who was standing there, on the day, before anyone knew what the day would be worth. That's why it carries weight months later. It's also why a vague one is so expensive.
What a site diary isn't
Four other daily documents get confused with it. You probably need most of them, and they do different jobs.
| Document | What it records | Who reads it |
|---|---|---|
| Site diary | What happened and why: events, conditions, deviations from the plan | Project and commercial team |
| Daily allocation sheet | Who worked on which task, where, for how many hours | QS, cost and productivity |
| Daily report | A summary sent upwards or to the client | Client, Project Manager, Principal Contractor |
| Foreman's report | Gang-level detail from one supervisor | Site manager, section engineer |
| Contractual notice | A formal notification, such as an NEC4 early warning or compensation event | The other party, through the contract's communication system |
That last row is where teams come unstuck. A diary entry is evidence of an event. It isn't the notification of it. Under NEC4 the notice goes through the communication system the contract specifies, and a line in the diary, however clear, doesn't do that job for you.
Why is a site diary kept?
A site diary is kept to create a contemporaneous record of site events that the project team, the commercial team and, if it comes to it, an adjudicator can rely on. It supports progress reporting, valuations, delay analysis and compensation events, and it defends claims long after everyone's memory of the day has gone.
Memory doesn't survive. Records do.
English courts have been plain about this. In Gestmin SGPS v Credit Suisse [2013] EWHC 3560 (Comm), Leggatt J said the best approach in a commercial case is to place little if any reliance on witnesses' recollections of meetings and conversations, and to base findings on the documentary evidence. On a construction job, your diary is a large part of that documentary evidence.
I learned this the expensive way. On the North West Electrification Programme I came close to losing £20 million, and the records existed. They were scattered across emails, spreadsheets, site vehicles and a supervisor's notebook nobody could find. By the time we'd pulled the evidence together, the commercial position had gone.
Under NEC4, the clock is already running
NEC4 ECC clause 61.3 is the reason commercial teams lose sleep. If the Contractor doesn't notify a compensation event within eight weeks of becoming aware that it has happened, the Prices, the Completion Date and the Key Dates aren't changed. The exception is an event arising from the Project Manager or Supervisor giving an instruction or notification, issuing a certificate or changing an earlier decision. Read more on the eight-week time bar.
Now do the maths on a diary nobody commercial reads until month end. Four weeks of an eight-week window can be gone before the QS sees the entry. That's half your time spent before anyone has started.
The diary feeds other NEC4 mechanisms too:
- Early warnings. Clause 15.1 asks the Contractor and the Project Manager to warn each other as soon as either becomes aware of a matter that could, among other things, increase the total of the Prices, delay Completion or a Key Date, or impair the performance of the works in use. The diary is usually where that matter first appears. See NEC4 early warnings.
- Weather. Under clause 60.1(13), weather is a compensation event only when a measurement within a calendar month, before the Completion Date for the whole of the works and at the place stated in the Contract Data, is shown to occur on average less often than once in ten years. Your diary records what the weather actually stopped; the contractual test needs the measurements. Keep both.
- Disallowed Cost. On the cost-based options, costs that aren't justified by the Contractor's accounts and records can be disallowed. Thin diaries make that argument easy for the other side. See NEC4 Disallowed Cost.
Outside NEC, the uses are just as practical: interim valuations and the cost value reconciliation, progress against the programme, handover between shifts, and defending a defects or delay claim years after the site has closed. For the full NEC4 workflow, read site diaries and NEC4 compensation events.
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What to record in a site diary each shift
The rule I give graduates: if it happened, write it down. If it was different from the plan, write it down in detail, with times.
| Field | What to record | Why it earns its place |
|---|---|---|
| Date, shift, author, area | Who wrote it, when, and which zone, chainage or grid it covers | Authorship and timing are what make a record contemporaneous |
| Weather | Conditions at start, midday and end of shift; rain, temperature, wind; anything it stopped | Shows the site effect. The NEC4 weather test uses separate measurements, so record both |
| Labour | Numbers by trade and subcontractor, hours, which gang did what | Cross-checks the daily allocation sheet and supports Defined Cost |
| Plant | What was on site and whether it was working, idle or broken down, with times | Idle plant is cost. Without times you can't price it |
| Work completed | Activity, exact location and quantities | Progress evidence against the Accepted Programme |
| Instructions | Who gave them, what was said, when, and whether verbal or written | A Project Manager's instruction changing the Scope is a compensation event under NEC4 clause 60.1(1) |
| Delays, access, interruptions | What stopped, start and end times, who was affected, what they did instead | Failure to give access can fall under clause 60.1(2). Redeployment is the cost story |
| Deliveries | What arrived, what was late, short or rejected | Supports supplier disputes and goods received notes |
| Visitors and inspections | Name, organisation, purpose, anything said or instructed | A conversation only becomes evidence once it's written down |
| Health and safety | Incidents, near misses, permits, inspections | Cross-reference the statutory registers; don't replace them |
| Photographs | Captioned with location, time and the entry they support | A photo without a caption is just a picture |
| Look-ahead | Tomorrow's plan, risks, decisions needed | The natural home for early warning candidates |
For a field-by-field breakdown, read what to include in a site diary. If weather is your biggest exposure, the weather delay log sits alongside the diary.
Site diary example: a completed entry
Here's an illustrative entry for one shift. The project, people and rates are invented for teaching. The structure is what I'd want to see on a well-run NEC4 job.
Tuesday 11 March 2025, day shift 07:30 to 17:30. Author: J. Patel, Section Engineer. £28M rail electrification package, NEC4 ECC Option C. Section 4, chainage 1200 to 1400.
Weather: 07:30 6°C, dry, light wind. 12:00 9°C, overcast. 17:00 7°C, light rain from 15:40. No weather stoppages.
Labour: 1 piling supervisor and 4 piling operatives (own). 6 groundworkers (subcontractor). 1 banksman.
Plant: Piling rig PR-02 on site from 07:30, not working all shift (see delays). 13t excavator working 07:30 to 17:30.
Work completed: Groundworkers excavated and blinded 6 OLE foundation bases, ch 1250 to 1320. Piling at Grid K3 to K8, planned for today on Accepted Programme Rev 3, not started.
Delays and access: Client's utility diversion works still occupying Grid K3 to K8 at 07:30. Rig and 4 piling operatives unable to start. Crew on plant maintenance 08:00 to 12:00, stood down from 12:00. Photos P11 to P14.
Instructions: 09:15, verbal, Project Manager on site: access to K3 to K8 expected Thursday 13 March. Written confirmation requested by email at 09:40.
Deliveries: 40m of 225mm duct at 10:20, complete, GRN 0412.
Look-ahead: Piling can't start until access is given. Passed to the commercial team for early warning and compensation event review.
What the QS does with that entry
- Reads it within days, not at month end. 11 March goes in the log as the likely awareness date for clause 61.3.
- Checks the contract basis. Has the Client failed to allow access by the later of the access date and the date on the Accepted Programme? That's clause 60.1(2). Then check the Z clauses, because amendments change everything.
- Notifies through the contract. The notice cites the diary entry and photos P11 to P14. If the access problem could increase the Prices or delay Completion, it's an early warning matter as well.
- Prices it from the records. For illustration: two days of rig at £3,200 a day plus four operatives at £280 a day each comes to £8,640, before Fee and any time effect. The real assessment follows the contract's Defined Cost rules and the dividing date.
Without that entry, the QS is trying to prove in May what a piling rig was doing on a Tuesday in March. Good luck with that. You'll find more good and bad entries, side by side, in our site diary examples.
How to write a site diary that holds up
Most diaries don't fail because they're empty. They fail because they're vague, late or written by one person who couldn't see half the job.
- Write it on the shift. Before you leave site, ideally as things happen. Tomorrow morning is already reconstruction.
- Facts, times and places. "Rig stood 07:30 to 12:00 at K3 to K8" is evidence. "Delays to piling" is a shrug.
- Record the deviation, not just the progress. "Pour Bay 4, 45m³" is fine. If the concrete arrived three hours late and pushed the pour into overtime, that's where the money is.
- Name the source of every instruction. Who, when, how it was given, and whether you've asked for it in writing.
- Caption every photograph and tie it to the entry it proves.
- Never backdate. If you've fallen behind, write the entry now, label it as late, and say what you relied on. An honest gap is better than a convenient one.
- Get it read. Someone commercial should review diaries at least weekly, against the programme and the contract.
The step-by-step version is in how to write a site diary. For why timing matters so much, see contemporaneous records, and for the end-of-shift sign-off, the completion checklist.
Common mistakes I still see
- Friday write-ups. One entry covering five days. It reads like what it is.
- "Weather: wet." Wet when? Wet where? What stopped?
- One author on six work fronts. Nobody sees a £30M job from one cabin. Use an entry per area, with a named person signing off the day.
- Opinions and blame. "Subbie useless again" will be read aloud in adjudication. Write what happened and let the facts carry it.
- Photos stuck in someone's camera roll. If it isn't attached to the entry, assume you'll never find it.
- Nobody commercial reads it until final account. They'll find the evidence. They'll also find it's time-barred.
- Treating the diary as the notice. It's the proof behind the notice, not a substitute for it.
Paper or digital, and how to choose a site diary app
Paper still works. A paper diary filled in every day beats an app nobody opens, and some sites have no signal and gloves that don't work on glass. The weak points are retrieval and integrity: finding 11 March in a box of books two years later, and proving the page you're relying on wasn't added afterwards.
| Question | Paper diary | Digital site diary |
|---|---|---|
| Cost to start | A book and a pen | Subscription or free template |
| Works with no signal | Always | Only if the app captures offline and syncs later |
| Photos linked to the entry | Separately, if at all | Attached, timestamped and often located |
| Finding one day two years later | Slow | Search by date, area or keyword |
| Several contributors per shift | One book, one pen | Many contributors, one sign-off |
| Proving when it was written | Hard | Edit history and locked entries, if the app keeps them |
| Commercial review | Someone has to read the book | Can be shared or flagged automatically |
What are some good site diary apps?
It depends what you need the diary to do. The options UK teams usually compare fall into three groups:
- Dedicated site diary and forms apps, such as SiteDiary, Sitemate's Dashpivot and Novade. Quick to roll out for daily records, checklists and forms.
- Whole-project platforms, such as Procore, where the daily log sits alongside drawings, RFIs and documents. Sensible if the business already runs on one.
- Commercial record systems built around the contract. Gather is one. It's a mobile site diary (iOS, Android and web, with offline capture, voice-to-text, timestamped GPS-tagged photos and automatic weather) whose AI QS reads each entry against the NEC contract and flags potential compensation events for the commercial team to check.
How to choose a site diary app
Ignore the feature grid for a minute and ask eight questions:
- Will a section engineer at the end of a 12-hour shift actually fill it in? Time a real entry on site.
- Does it capture offline and sync later?
- Are photos timestamped, located and attached to the entry they prove?
- Does it lock entries and keep an edit history?
- Can several people contribute per area, with one person signing off the day?
- Does it record weather automatically and still let you write what the weather stopped?
- Can you export a clean, dated PDF of any day for an adjudicator?
- Does anyone commercial get told when an entry matters, or does it sit in a database until final account?
Not ready for software? The free site diary template has an online builder: fill in the fields, add photographs and save the day as a PDF, with no registration.
Is a site diary a legal requirement? And how long should you keep it?
In most cases the requirement is contractual, not statutory. Check the project contract, Scope or specification and your organisation's procedures for the records you must keep. On the NEC4 cost-based options, your accounts and records also decide which costs survive as Defined Cost.
Some site records are statutory in their own right. Regulation 12 of the Work at Height Regulations 2005 requires the result of each inspection of certain work equipment to be recorded and kept. Regulation 24 of the CDM Regulations 2015 requires a written report when an inspection of an excavation, cofferdam or caisson finds the work can't be carried out safely. Keep those in their own registers and cross-reference them from the diary. A diary supports project administration. It doesn't replace separate contractual, safety or statutory processes.
How long to keep site diaries
| Situation (England and Wales) | Limitation period | Source |
|---|---|---|
| Contract signed under hand (simple contract) | 6 years from when the cause of action accrued | Limitation Act 1980, s5 |
| Contract executed as a deed | 12 years from when the cause of action accrued | Limitation Act 1980, s8 |
| Defective Premises Act claims | 15 years; 30 years for rights of action that accrued before the change came into force | Building Safety Act 2022, s135 |
My advice: keep site diaries for at least 12 years after completion on any deed, longer on residential work caught by the Defective Premises Act, and indefinitely while a dispute or insurance claim is live. A cause of action can accrue after completion, so treat these periods as floors, not deletion dates. Scotland and Northern Ireland have their own rules. The full schedule by record type is in site diary record retention.
More site diary guides
Site diary explained
Frequently asked questions
What is a site diary in construction?
A site diary is the dated, daily record of what happened on a construction site: work done and where, labour and plant, weather, instructions, delays, deliveries, visitors and photographs. It's written on the day by the people who saw it, and later valuations, compensation events and disputes rely on it.
Why is a site diary kept?
To create a contemporaneous record the project can rely on later. It supports progress reporting, valuations, delay analysis and compensation events. Judges have said they'd rather rely on documents than memory: in Gestmin SGPS v Credit Suisse [2013] EWHC 3560 (Comm), the High Court said little if any reliance should be placed on witnesses' recollections of meetings and conversations, and findings should rest on the documentary evidence.
Why is it important to keep a construction site diary?
Because time and money follow evidence. Under NEC4 clause 61.3, a compensation event the Contractor doesn't notify within eight weeks of becoming aware of it doesn't change the Prices or the Completion Date, unless it arose from a Project Manager or Supervisor instruction, notification, certificate or changed decision. A good diary is how teams spot events in time. It also defends defect and delay claims years later.
What are some good site diary apps?
UK teams usually compare dedicated diary and forms apps (SiteDiary, Sitemate's Dashpivot, Novade), whole-project platforms with a daily log (Procore), and commercial record systems such as Gather, which reads entries against the NEC contract. Choose on offline capture, timestamped photos, edit history, PDF export, and whether anyone commercial is alerted when an entry matters.
How can I create an online site diary for free?
Use a free browser-based form or template. Our free site diary template includes an online builder: fill in the fields, add photographs and save the day as a PDF from your browser, with no registration. An Excel version is there too. For a team, keep completed entries somewhere shared and backed up.
Is a site diary a legal requirement in the UK?
Usually the requirement is contractual rather than statutory. Check the project contract, Scope or specification and your organisation's procedures for required records. Some site records are statutory, such as inspection records for work at height equipment under regulation 12 of the Work at Height Regulations 2005. A diary supports project administration but does not replace separate contractual, safety or statutory processes.
Who should write the site diary?
The person with direct knowledge of the work: usually the site engineer, section engineer, foreman or site manager. On jobs with several work fronts, write one entry per area or shift and have a named person sign off the day. Someone from the commercial team should read the entries at least weekly.
How long should site diaries be kept?
In England and Wales, at least six years from when a cause of action accrues under a simple contract and twelve years under a deed (Limitation Act 1980, sections 5 and 8). Defective Premises Act claims can run for 15 years, or 30 for older rights, after the Building Safety Act 2022. Hold everything while a dispute is live. See record retention.
Can a site diary be used as evidence in adjudication?
Yes. A site diary is documentary evidence, and its weight depends on who wrote it, when, how detailed it is and whether it agrees with the other records. A same-day entry with captioned photographs is far harder to challenge than one written up a week later.
Does a site diary entry notify a compensation event?
No. Under NEC4, a compensation event is notified through the communication system the contract specifies. The diary entry is the evidence behind the notice, not the notice. Use the diary to fix the facts and the awareness date, then notify within the eight weeks set by clause 61.3.
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