Site Management · Best Practice · Pre-Construction

Security Plan

The Security Plan addresses the protection of the construction site from unauthorised access, theft, vandalism, and trespass. It covers perimeter fencing, access control systems, CCTV, lighting, security patrols, and material storage arrangements. Effective site security also reduces the risk of injury to members of the public, particularly children, who may be attracted to the site.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. CDM 2015 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Site Security — Protecting Workers, Public, and Assets

Site security is not only about protecting materials from theft — it is primarily about protecting the public and preventing accidents. An unsecured construction site is a foreseeable hazard, particularly for children. CDM 2015 Regulation 13 places a mandatory duty on the Principal Contractor to prevent unauthorised access.

Construction sites are also prime targets for arson — combustible materials, incomplete fire compartmentation, disabled detection systems, and unoccupied buildings out-of-hours all contribute to the risk.

“Children entering a construction site represent the highest-risk unauthorised access scenario” — Children are attracted to construction sites. If a child is injured on an unsecured site, the Principal Contractor faces civil liability regardless of 'no trespass' signage — the Occupiers' Liability Acts impose a duty even for trespassing children. A minimum 2.4m hoarding with no accessible footholds is the baseline requirement.

Security Plan — Key Elements

Element	Content
Perimeter security	Hoarding/fencing specification. Height (min 2.4m). Anti-climb measures. No gaps. Regular checks.
Gates and access	Main gate locked when unattended. Emergency gate lockable but accessible to FRS. Access points minimised.
CCTV	Coverage of perimeter, access points, plant storage, high-value materials. Monitored or recorded. Storage min 30 days.
Lighting	Perimeter lighting. Internal security lighting. Sensor-triggered for intrusion detection.
Manned guarding	Where required (24/7 on high-value/high-risk). Security company details. Patrol schedule.
Plant security	Plant immobilised when not in use. Keys removed and secured. GPS tracking on high-value.
Materials storage	High-value in locked stores. LPG secured. Fuel in bunded locked tanks.
Arson prevention	Combustible materials away from perimeter. No accessible materials at perimeter for external ignition. Waste cleared regularly.
Out-of-hours contact	Security contact number. Police 101. Emergency 999.

Common Mistakes

Gaps in hoarding — especially at corners and junctions. Children are expert at finding the smallest gaps. Perimeter integrity must be checked daily. Gaps must be repaired immediately.

Plant left unlocked or with keys in overnight — an invitation to joy-riding and theft. All plant: engine disabled, keys removed and secured, not left in the cab. High-value plant GPS tracking activated.

No CCTV covering perimeter — a powerful deterrent for out-of-hours intrusion and arson. On a site of any significant size, CCTV with ARC monitoring provides 24/7 oversight. The security plan must assess and specify coverage, storage, and monitoring.

Combustible materials stored at perimeter — accessible from outside. Materials stored against hoarding can be ignited by an arsonist from outside without breaching security. They must be stored away from the perimeter fence.

No out-of-hours contact or response — if an alarm activates, someone must respond. The plan must name who is contacted, confirm the number is monitored out of hours, and define the response protocol. An alarm that activates without response provides no protection.

Frequently Asked Questions

What height of hoarding is required?

CDM does not specify a height, but HSE guidance and industry practice establish 2.4m (8 feet) as the standard minimum. Anti-climb measures should be used in higher-risk locations. Public-facing locations prefer solid hoarding over see-through mesh. Specific planning conditions may impose additional requirements.

Is manned guarding required on all sites?

There is no statutory requirement — it is a risk-based decision. Manned guarding is typically justified where: high-value plant/materials (above approximately 50,000); high-crime location; previous thefts/vandalism; extended duration (18+ months); or CCTV is insufficient. The security plan should document the decision-making.

How does GDPR apply to site CCTV?

Site CCTV is subject to UK GDPR and DPA 2018. Requirements include: signage at all cameras (who operates, purpose, contact); retention limited (typically 30 days); restricted access; and documentation of lawful basis. Signs and retention policy should be referenced in the security plan.

Who is responsible — the PC or the client?

CDM places the duty on the Principal Contractor during the construction phase, regardless of site ownership. The client may have obligations for occupied building parts outside the construction phase. Security costs should be addressed pre-contract.

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