Nobody keeps a site diary because it is interesting. It is kept because of the one week in five years when it is the only evidence of what happened, and by then it is far too late to start.
The test of a diary is not whether it was filled in. It is whether an adjudicator reading it two years later can tell what happened without asking you. Most site diaries fail that test, and they fail it in the same four ways.
What makes an entry worth anything
It was written the same day
This is the whole game. A contemporaneous record — written before anyone knew there would be an argument — carries weight precisely because it could not have been written to win. A diary reconstructed in November from memory and invoices is worth very little, and everyone in the room will know it was reconstructed, because reconstructed diaries are suspiciously tidy.
It records the weather as a fact, not a feeling
“Rain” is not a record. “Rain from 06:00, stopped 11:20, no concrete pour, 6 of 9 on site sent home” is a record. On a delay claim, the weather entry only helps if it connects the weather to the work that did not happen.
It says who was actually there
Numbers by trade, not a total. Eight people on site tells you nothing; two bricklayers and six general workers on a day the programme wanted six bricklayers tells you exactly why the week slipped.
It captures instructions on the day they are given
Every verbal instruction, who gave it, and what you did about it. This is the single most valuable line in a site diary and the one most often left blank — see variations for why.
The columns
| Column | What good looks like |
|---|---|
| Date and weather | Times, not adjectives. Note when work stopped and when it restarted. |
| Labour on site | By trade, with numbers. Include subcontractors and name them. |
| Plant and equipment | What was on site and whether it worked. Standing plant is a cost. |
| Work done | Located, not general. “Slab poured” vs “GF slab, grid A–D, poured and floated”. |
| Deliveries | What arrived, from whom, and what was short or rejected. |
| Instructions and visitors | Who came, what they said, what you did. |
| Delays and stoppages | The reason and the hours. A delay with no recorded cause is a delay you absorbed. |
| Safety and incidents | Anything at all, however minor. This is also a legal record. |
Photographs are part of the diary, not a substitute for it. A phone photo carries its own date and time, which makes it strong evidence — but only of what is in frame. The diary is what explains why the photo was taken.
The habit that actually sticks
Every site diary system fails the same way: it is filled in properly for three weeks and then abandoned, because it takes twenty minutes and the twenty minutes happen at the end of a long day. The only diaries that survive are the ones that take under three minutes and are done on site, before leaving — not at the desk, and never on a Friday for the whole week.
If a template is the thing that makes it three minutes, use the template. If a phone is the thing, use the phone. What does not work is intending to remember.