Construction Phase Plan Calculator

The construction phase plan (CPP) is required under CDM 2015 for all construction projects. It records the arrangements for managing health and safety during the construction phase. It must be prepared before construction work begins and kept up to date throughout.

The principal contractor prepares the CPP for projects with multiple contractors. For single-contractor projects, the contractor prepares it. The plan should build on pre-construction information provided by the client and principal designer.

Appendix 3 of HSE guidance L153 (the official guidance to CDM 2015) lists the expected contents: project description; management of the work — site rules, cooperation and coordination, worker involvement, site induction, welfare facilities, and fire and emergency procedures; and arrangements for controlling the significant (Schedule 3) risks. The plan must be proportionate to the scale and complexity of the project, so the level of detail varies — a simple domestic job may need only a short document.

Best practice is weekly or fortnightly toolbox talks covering relevant safety topics. On larger sites, daily briefings may be needed. Topics should relate to current work activities - e.g., work at height before roof work begins, manual handling before heavy deliveries.

Yes, CDM 2015 applies to all construction work regardless of size. For small projects, the CPP can be a simple document covering key risks, emergency procedures, and welfare arrangements. A one-page plan may be sufficient for straightforward domestic work.

CDM 2015 Schedule 2 requires welfare facilities to be "suitable and sufficient" — it sets no fixed legal ratio. As a benchmark, BS 6465-1:2006 / HSE CIS59 suggest about 1 chemical toilet per 7 people on a 40-hour week with weekly servicing; revised BS guidance trends toward 1:5, and a site serviced daily can run closer to 1:10. Washbasins must be provided in the immediate vicinity of every WC (Schedule 2, para 2), so wash stations should track the number of toilets roughly 1:1, with hot or warm running water. This calculator uses the 1:7 benchmark and matches wash stations to toilets — adjust for your actual servicing arrangements.

No. The risk-assessment, method-statement, toolbox-talk and welfare figures are indicative planning estimates, not legal minimums. CDM 2015 (reg 12 and Schedule 2) and HSE L153 Appendix 3 require the plan and facilities to be proportionate and "suitable and sufficient" for the actual work, with no prescribed counts. Use the figures as a starting point and tailor them to the specific activities and risks on your site.