Guide · CDM 2015

CDM 2015 compliance,
and the software for it.

The Construction (Design and Management) Regulations 2015 apply to every project in Great Britain. This guide sets out the duty holders, when a project is notifiable, and the handover file.

Published 1 August 2026 · Last reviewed 23 September 2026

Run the CDM checklist → See the H&S module

Construction professionals reviewing plans on a UK site

The duty holders

Five roles, and most firms
hold more than one.

The commonest mistake is assuming the duty sits with somebody else. On a small job the same business is frequently the client's contractor, the principal contractor and the only contractor, which means holding three sets of duties at once.

01Client: Makes suitable arrangements for managing the project, allows adequate time and resources, and ensures the other duty holders carry out their duties. On a domestic project the duty normally passes to the contractor or principal contractor.
02Principal designer: Appointed where more than one contractor is involved. Plans, manages and monitors the pre-construction phase, and coordinates the information that feeds the construction phase plan and the file.
03Principal contractor: Appointed where more than one contractor is involved. Plans, manages and monitors the construction phase, draws up the construction phase plan, secures the site and organises cooperation between contractors.
04Designer: Eliminates foreseeable risks so far as reasonably practicable when preparing or modifying a design, and provides information about remaining risks.
05Contractor: Plans, manages and monitors their own work, and does not start on site until they are satisfied the necessary welfare and the construction phase plan are in place.

Notification and the plan

Two thresholds, and one document.

When to
notify

F10

A project is notifiable to the HSE if construction work is scheduled to last longer than 30 working days and have more than 20 workers working simultaneously at any point, or exceed 500 person days.

Client gives notice
As soon as practicable before setting up
Notice displayed on site
Notification does not change the duties

Duty · ClientStatutory

Construction
phase plan

CPP

Required on every project, not only notifiable ones, and it must exist before construction work starts. Proportionate to the job: a short document on a small one, and no less real for that.

Site rules and arrangements
Significant risks and controls
Welfare provision
Reviewed as the job changes

Duty · Principal contractorStatutory

Health and
safety file

File

Required where more than one contractor is involved. It is for whoever maintains, cleans, refurbishes or eventually demolishes the structure, and it is handed to the client at the end.

Residual hazards
Key structural principles
Services and their isolation
Kept and updated by the client

Duty · Principal designerStatutory

Welfare
from day one

Sch 2

Schedule 2 welfare is not a nice-to-have and not something to arrange in week two. It must be in place from the moment work starts.

Sanitary conveniences
Washing facilities
Drinking water
Rest and changing facilities

Duty · ContractorStatutory

Not legal advice

This guide is written for site and commercial staff who need the shape of the regulations, not a definitive statement of them. Read it alongside the HSE's own guidance, and take advice where a duty is contested or a project is unusual.

Where Unibuild helps

The evidence is already
where the work happened.

Unibuild holds the evidence against the project, current and attributable, so the information the file needs is retrieved rather than hunted for. The duties stay with the duty holder.

Site paperwork and site records held against the project in Unibuild

During the job

RAMS signed at the gatePermits issued and closedToolbox talks with signaturesNear misses and accidentsPlant compliance

At handover

The records that go into the fileTraining matrixWelfare confirmationsRecords against the project

What stays yours

The dutiesThe notificationThe judgement callsThe signature

The HSE letter Ten working days to produce the records With Unibuild · retrieved by project, not searched for

CDM 2015 software

What CDM compliance software
does on a running job.

The duty stays with the duty holder. CDM compliance management software records what was done, keeps that evidence attributable and retrievable, and puts an expiry in front of somebody before it lapses. Six places where that work lands on a construction project, and what Unibuild does in each.

01Notifiable jobs, flagged at creation: Every project record carries an explicit F10 flag marking the job notifiable to the HSE, set when the project is opened and visible on the project detail page, the client portal and the staff mobile app, next to a second flag recording whether you hold the principal contractor position. Every notifiable job on the system can be listed at once rather than recalled. Sending the notification itself remains the client's duty. (Regulation 6)
02The construction phase plan, held and issued: The project holds a dedicated area for the construction phase plan. Each plan is stored with its title, the original filename, the uploading user and the date and time, and it publishes to the client portal and the client app on upload, as a live file rather than an emailed copy, so a revision is an upload instead of a reprint and a delivery run. Drawing up the plan is the principal contractor's work. (Regulation 12)
03RAMS a named operative actually accepted: RAMS are held per job, each with its documents and its own approval status, so the office reviews and approves before they reach site. The app checks that RAMS exist for the job before work proceeds, lists the current documents and lets the operative read them on the phone. When an operative reviews and accepts them the platform records who, which job, when, and captures a signature, tied to the document that was current that day. Most systems can show a document existed. Very few can show who accepted which version of it.
04Briefings signed one person at a time: A toolbox talk is scheduled against a project and a named presenter, drawn from a library of prepared templates, delivered on site, concluded, then signed by each attendee individually on the phone screen, every signature stored with the exact time it was given. Attendance is recorded per person rather than as a head count, with a free text field so agency labour, subcontractors' operatives and visitors sit on the same register as employed staff. The app will not take a signature against a talk still marked as scheduled, so a register cannot be signed in advance.
05Permits raised before the work, not after it: Hot work, work at height, task specific ladder and steps, lone working, limitation of access, and the four part safe isolation permit with its switching schedule. Each is raised on the phone on site and stamped with the time it was created and the user who created it, so a permit written up after the event shows that it was. The office can add, rename and reorder the questions without a code change or an app release, and every permit stores the questions and answers as they stood on the day, so a historic permit keeps the wording that was actually asked. The five site permit types are exposed read only to the client portal and the client app.
06Expiry watched, and one thing enforced: The training matrix, the e-learning matrix and the staff certificate registers each hold a per person expiry date, banded onto one dashboard page with a thirty day window, which is where the competence evidence behind an appointment decision comes from. Subcontractors go further. A nightly job reads the certificate and insurance registers and removes any firm whose cover has lapsed from approved status, with the reason stamped on the record, which withdraws that firm from the subcontract order form, the small works order form and the labour planner. On one live deployment that automatic stamp sits on 62 of 164 subcontractor records. (Regulation 8)

What stays with you

Unibuild records, evidences and prompts. It holds and organises the information that goes into the health and safety file, with near miss and accident reports, sign-off records and site photographs retained against the project and their provenance intact. Risk assessment, competence decisions, professional judgement and statutory notification stay with the duty holder, which is where the regulations put them.

If you want to know where you stand before you look at any system, work through the free CDM checklist template first: 22 duties across pre-construction, the construction phase and the paperwork, each with the regulation it comes from, and nothing to sign up for.

The duties side by side

Who appoints whom,
and what each one owes.

The same five roles as a grid. On a single-contractor project the principal designer and principal contractor roles do not arise, and on a domestic project the client's duties normally pass to the contractor.

Duty holders Documents

CDM 2015 duty holders, appointment triggers and principal obligations
Duty holder	When the role exists	Appointed by	Owes, principally	Reg
Client	Every project, commercial or domestic	Not appointed. It is whoever the work is carried out for.	Suitable arrangements for managing the project, adequate time and resources, and ensuring the others carry out their duties	4
Principal designer	More than one contractor	The client, in writing	Plans, manages and monitors the pre-construction phase; prepares and updates the health and safety file	5, 11, 12
Principal contractor	More than one contractor	The client, in writing	Plans, manages and monitors the construction phase; draws up the construction phase plan; secures the site; organises cooperation	5, 12, 13
Designer	Anyone preparing or modifying a design	Not appointed as such. The duty follows the activity.	Eliminate, reduce or control foreseeable risks so far as reasonably practicable, and provide information about what remains	9
Contractor	Anyone carrying out construction work	The client or the principal contractor	Plans, manages and monitors their own work; does not start until welfare and the construction phase plan are in place	15

What has to exist, on which projects, and who owns it
Document	Required on	By when	Owned by	Reg
Construction phase plan	Every project, notifiable or not	Before construction work starts	Principal contractor, or the contractor where there is only one	12(1), 15(1)
Health and safety file	Projects with more than one contractor	Prepared through the job, handed over at the end	Principal designer, then the client keeps and updates it	12(5)
F10 notification	Longer than 30 working days with more than 20 workers simultaneously, or over 500 person days	As soon as practicable before setting up the site	Client. Notice displayed on site.	6
Pre-construction information	Every project	Before appointing designers or contractors	Client	4(4)
Schedule 2 welfare	Every project	From the moment work starts, not week two	Contractor, enforced by the principal contractor	Sch 2

Notification does not change who holds a duty. A project can be notifiable and still be run badly, and a project below both thresholds still needs a construction phase plan, welfare from day one and a client who has made suitable arrangements. Work through the 22-duty CDM checklist against one of your own jobs.

Questions

What firms ask before
they put CDM on a system.

Is CDM 2015 software a legal requirement?

No. CDM 2015 places duties on people, not on systems, and nothing in the regulations obliges you to buy anything. A firm running one small job can meet every duty on paper. What software changes is whether you can find the evidence afterwards: who accepted which version of the RAMS, when the toolbox talk was signed and by whom, whether the permit was raised before the work or written up after it. That is the part that fails under audit, and it is the part a system is genuinely good at.

What should CDM 2015 software actually do?

Three things, and it is worth being suspicious of a list much longer than this. It should record what was done in a way that ties the record to a named person and a moment in time. It should keep that evidence retrievable years later, with the wording that was current on the day rather than today's version. And it should put an expiry in front of somebody before it lapses, rather than after. Everything above on this page is one of those three.

Who writes the construction phase plan?

The principal contractor. Drawing up the construction phase plan turns on judgements about the specific job. Unibuild holds the plan against the project with its filename, uploader and timestamp, and publishes it to the client portal on upload, so a revision is an upload rather than a reprint and a delivery run.

Who submits the F10?

The client notifies the HSE, which is usually news to the client. Unibuild flags the project as notifiable when it is opened, shows that flag on the project page, the client portal and the staff app, and lets you list every notifiable job at once instead of recalling them. The two thresholds are set out here.

We are a small contractor. Is this proportionate?

CDM 2015 applies to every construction project regardless of size, including domestic work, so the duties are the same. The volume of evidence is not. A firm running three jobs can hold RAMS acceptance and toolbox talk signatures perfectly well without a platform. The point at which it stops working is usually when nobody can say which version of a document an operative saw, or when a certificate expires and nobody notices for eight months.

How does it handle subcontractor competence and insurance?

A nightly job reads the certificate and insurance registers and removes any firm whose cover has lapsed from approved status, with the reason stamped on the record. That firm then drops out of the subcontract order form, the small works order form and the labour planner, so ordering from them becomes a deliberate override rather than an oversight. On one live deployment that automatic stamp sits on 62 of 164 subcontractor records. The subcontractor portal is the self-service side of the same register.

The duties, as they
arrive on a real job.

The regulations set out who holds what. These are the moments on site where a duty stops being a paragraph and starts being a decision somebody has to make that morning.