6 questions answered · Updated 5 March 2026
Answers to the most common questions about construction site diaries — what to include, who fills them in, legal requirements, and digital alternatives.
A construction site diary should record: date, weather conditions (temperature, wind, rainfall), workers on site (names, trades, company), visitors and their purpose, deliveries received, plant and equipment on site, work activities carried out, any delays and their causes, health and safety observations, instructions received or given, and any incidents or near-misses. Under CDM 2015, the principal contractor must maintain adequate records of site activities.
While there is no specific law that says 'you must keep a site diary', CDM 2015 Regulation 12(5) requires the principal contractor to keep records of arrangements for managing the project. Site diaries serve as evidence of compliance with health and safety duties. In practice, the HSE expects to see contemporaneous records during investigations, and courts give significant weight to site diary entries in dispute resolution. Most standard form contracts (JCT, NEC4) also require daily records.
The site manager or site agent is typically responsible for completing the daily site diary. On larger projects, each section supervisor may maintain their own diary, with the principal contractor's site manager maintaining the master record. Subcontractors should also keep their own records. The key is that whoever fills it in should do so on the day — not retrospectively — as courts place more weight on contemporaneous records.
Construction site diaries should be retained for a minimum of 6 years after project completion (the limitation period for contract claims under the Limitation Act 1980). For projects involving a deed (most construction contracts), the limitation period extends to 12 years. For health and safety records, the HSE recommends retention for at least 40 years where there is any potential for latent health conditions (e.g., asbestos exposure). In practice, most firms retain site diaries indefinitely in digital format.
Yes, digital site diaries are fully acceptable and increasingly preferred. There is no legal requirement for site diaries to be on paper. Digital diaries offer advantages: GPS-stamped entries prove location, timestamps prove contemporaneity, photos can be embedded directly, entries cannot be retrospectively altered (audit trail), and they are backed up automatically. The key legal requirement is that records are contemporaneous, accurate, and retrievable — digital diaries meet all three criteria more reliably than paper.
Failing to maintain site diary records can have serious consequences. In HSE investigations, the absence of records creates a presumption that proper management was not in place. In contractual disputes, you lose your ability to evidence delay events, instructions, and variations — courts will prefer the other party's records. Insurance claims may be rejected without contemporaneous evidence. And in personal injury claims, the absence of safety records makes defending the claim significantly harder.