A site diary is the daily record of what actually happened on a construction or demolition site: who was there, what work was done, what was delivered, what the weather did, and what got in the way. Kept properly, it is the single most valuable document a contractor holds when a project ends up in a dispute — and one of the most neglected pieces of admin on site when it doesn’t.
This guide covers what a site diary should record, who should keep it, why it matters commercially, what a good template looks like — and how AI and voice capture are removing the reason site diaries go unwritten.
What is a site diary?
A site diary (also called a daily site record, daily log or daily report) is a contemporaneous, day-by-day account of site activity, usually kept by the site manager, agent or supervisor. Its defining quality is that it is written on the day, while the facts are fresh — which is exactly what gives it evidential weight later. A diary reconstructed weeks afterwards is worth very little.
Why keep a site diary? The commercial case
- Delay and disruption claims — extension of time and loss and expense claims stand or fall on contemporaneous records. The diary is the primary evidence of what happened, when, and what it affected.
- Variations — instructions given verbally at the workface have a habit of being disputed at final account. A diary entry made the same day is often the only record that the instruction existed. (See our companion guide to variation orders in construction.)
- Defects and quality disputes — records of conditions, hold points and inspections protect you long after handover.
- Health and safety — the diary corroborates briefings, inspections and incidents alongside your formal records such as RAMS and POWRAs.
- Progress and productivity — a consistent diary is a free dataset on how your sites actually perform, if anyone ever analyses it.
Under most standard forms — JCT, NEC and bespoke contracts alike — the party with the better records wins the argument. Adjudicators and quantity surveyors say it constantly: no records, no claim.
What should a site diary include?
- Date, project, author — and the shift or working hours covered.
- Weather — conditions through the day, and any time lost to them.
- Labour on site — numbers by trade and subcontractor, including visitors and deliveries drivers where relevant.
- Plant and equipment — what was on site, working, standing or broken down.
- Work carried out — by area/activity, with quantities where practical.
- Deliveries and materials — received, rejected, or awaited.
- Instructions received — from the client, principal contractor or designer, especially verbal ones.
- Delays, disruption and stoppages — cause, duration, areas and trades affected.
- Health and safety — briefings, inspections, near misses, incidents.
- Visitors — client, designers, HSE, utility companies.
- Photos — dated progress and condition photos referenced from the entry.
Who should keep the site diary — and when?
The person running the site day to day: the site manager, site agent, foreman or supervisor. On larger jobs each section or subcontractor may keep their own. The golden rules are the same at any scale: written the same day, by someone who was there, covering every working day — including the uneventful ones. A diary with gaps invites the question of what else is missing.
Paper, spreadsheet or site diary app: which format?
| Format | Strengths | Weaknesses |
|---|---|---|
| Paper diary | Simple, no setup, works anywhere | Illegible, easily lost or damaged, unsearchable, stays in the cabin |
| Spreadsheet / Word template | Structured, cheap, searchable | Done back at a desk (so often late), no photos, easy to backfill |
| Site diary app | Time-stamped, photos attached, backed up, searchable across projects | Subscription cost; still relies on someone typing at the end of a long day |
| AI / voice-captured diary | Spoken on site in minutes, structured automatically, consistent fields, analysable at scale | Emerging category; needs sensible setup and review discipline |
How is AI changing the site diary?
The site diary fails for one reason: it is done last, at the end of the day, by the most stretched person on site. Assistive AI attacks that friction directly, and the capability is developing fast:
- Voice capture — the site manager talks through the day while walking the site or driving off it; the diary writes itself into the correct fields, rather than being typed from memory at 6pm.
- Automatic context — date, weather, project details and expected activities pre-filled from data that already exists, so the human adds only what actually happened.
- Structured, consistent records — every entry captures the same fields, which is what makes diaries usable as evidence and as data.
- Cross-referencing — flagging when a diary entry records a verbal instruction with no matching variation order, or a delay with no notice issued — the gaps that cost real money at final account.
- Portfolio insight — analysing diaries across sites to surface recurring causes of lost time.
These are capability areas rather than measured client outcomes — but the direction is the same one already visible in AI-assisted RAMS drafting and point of work risk assessments: take the documentation burden off site staff without losing the rigour. In demolition — short programmes, changing workfaces, heavy compliance load — the value is especially direct; see our guide to AI in demolition and our work on operational efficiency for demolition contractors.
Site diary FAQs
Is a site diary a legal requirement?
Not as such — no statute mandates a site diary by name. But contracts commonly require progress records, and duties under CDM 2015 and health and safety law are far easier to evidence with one. In practice, the commercial risk of not keeping one is the compelling reason.
What is the difference between a site diary and a daily report?
Largely terminology. A daily report is often a formatted summary issued to the client; the site diary is the keeper’s own contemporaneous record. Many contractors produce the report from the diary.
How long should site diaries be kept?
At least as long as the limitation period on the contract — six years for a simple contract, twelve for a deed in England and Wales. Digital storage makes keeping everything trivial.
Can a site diary be used as evidence?
Yes — contemporaneous site records are routinely relied on in adjudication, arbitration and litigation, and are generally given more weight than witness recollection after the event.
What makes a site diary useless?
Backfilling several days at once, vague entries (“worked in Area B”), missing days, and diaries that never leave site. Consistency and same-day completion are worth more than elegant prose.
Stop losing the record that wins the argument
Surtori helps construction and demolition contractors use assistive AI to make daily records — site diaries, POWRAs, RAMS — something site teams can keep properly without the evening admin. If your diaries only get written when something has already gone wrong, book a discovery call.