Insight · Reducing risk

The O&M manual, and why
handover takes a fortnight.

Everything the building owner needs, in one file, assembled at the end from records made over a year. Why that is the wrong way round, and what it costs when the certificates cannot be found.

Published 28 August 2026·7 min read·Written by Darshan Parmar, Founder

The operation and maintenance manual is the one deliverable on a construction project that is assembled entirely from records made months earlier by people who have moved on. That is why it takes a fortnight, why it is late, and why the last payment sits behind it.

What an O&M manual is for

It is the document the building owner uses to run the building after you have gone. Not a compliance artefact, though it does compliance work: a caretaker with a leaking valve should be able to find out what the valve is, who supplied it, how to isolate it and who to ring.

That test is worth applying to the manuals you produce, because a great many of them fail it. A folder of manufacturers' PDFs in no particular order technically contains the answer and does not deliver it.

What goes in one

Contents vary by contract and by building, and the specification will say. In practice the recurring sections are:

A description of the works, what was built and to what specification.
As-built drawings, reflecting what is actually there rather than what was designed.
Plant and equipment schedules, with location, make, model and serial number.
Operating instructions for anything that has to be operated.
Planned maintenance requirements, with intervals, which becomes the owner's PPM schedule on day one.
Test and commissioning results, in full rather than in summary.
Statutory certificates. Electrical installation certificates, gas safety, fire alarm and emergency lighting commissioning, lifting equipment, pressure systems, air tightness.
Warranties and guarantees, with their start dates and what voids them.
Supplier and subcontractor contact details, which is the section most used and least maintained.
The health and safety file required under CDM 2015, which is a distinct document with a distinct purpose and is frequently bound in alongside.

Every one of those items existed on site, correct and available, at some point during the job. Handover is the process of finding them again.

The health and safety file is not the O&M manual

They get merged and they are different. The health and safety file, required by CDM 2015 on projects with more than one contractor, exists to tell anyone carrying out future construction work what they need to know to do it safely: residual hazards, structural principles, where the services run, what was left in the ground.

The O&M manual tells the occupier how to run the building. One is for the next builder, the other for the current caretaker. Binding them together is fine. Writing one and calling it both is not, and it is the version an inspector notices.

Handover, and the golden thread

For higher-risk buildings the Building Safety Act has made this considerably sharper. The golden thread requires building safety information to be held digitally, kept accurate, and handed on in a form the next duty holder can actually use. A box of paper does not satisfy it and neither does a folder of scanned PDFs with no structure.

The practical effect reaches well beyond in-scope buildings, because clients who commission both kinds of work are increasingly specifying the same standard on everything. Gateway 2 covers what that means before you start on site; this is the same discipline arriving at the other end of the job.

Why it is always late

The reasons are consistent across firms and almost none of them are about the manual itself:

It is started at the end. The manual is treated as a document to be written rather than a file to be filled, so the work begins when the job is finished and everyone who knows anything has been reassigned.
Certificates are held by whoever produced them. The electrical certificates are with the electrical subcontractor, whose commercial relationship with you is now about the final account, and chasing them is a negotiation rather than an errand.
As-builts were never maintained. Changes were made on site, agreed verbally, and never marked up, so producing as-builts means a survey.
Commissioning results are in emails. They exist, they are correct, and they are in one engineer's inbox.
Nobody owns it. It falls between the project manager who has moved to the next job and the commercial team who want the retention released.

The fix is upstream, not at handover

The only durable answer is to stop treating the manual as an end-of-job document and start treating it as a file that fills itself as the job runs. That means the certificate is filed against the project on the day it is issued, the commissioning sheet is uploaded when the engineer signs it, and the as-built markup happens at the point the change is agreed rather than nine months later.

None of that is more work in total. It is the same work, done once, at the moment when the person doing it knows the answer. The fortnight at the end is what you pay for deferring it.

There is a commercial reason to care beyond tidiness. On most contracts the manual is a condition of practical completion, or of the release of the first half of retention, or both. A manual that is two weeks late is two weeks of retention held, and retention held is the money that most often goes uncollected.

Where this touches the platform

Unibuild does not write your O&M manual and does not assemble it into a bound deliverable. What it does is hold the parts while the job is running, which is the half that fails. Certificates and commissioning documents are stored against the project with the uploading user, the original filename and the date and time. The asset register carries plant with its location, make, model and serial number, which is the schedule section most often rebuilt from scratch at the end. Subcontractor records hold the contact details that the manual's most-used section depends on. Where a client portal is in use, documents publish to it on upload as live files rather than an emailed copy, so a revision is an upload instead of a reprint and a delivery run. The manual is still yours to compile; what changes is whether compiling it means searching.

Documents and certificates Assets and inventory The client portal Compliance and certification

Where to start, on Monday

Take a live job that is three months from completion and ask one question: if we handed over on Friday, which sections could we produce today. Not could we get them, could we produce them. The sections that fail that test are the ones to start filling now, while the people who hold the documents still want something from you.

The single highest-value habit is filing statutory certificates against the project on the day of issue. It is thirty seconds each, it happens while the subcontractor still has an interest in your goodwill, and it removes the largest single cause of a late manual.

Sources

Checked against the source rather than against commentary. Where a schedule, a rate or a threshold is definitive on a government site, read it there.

Building Safety Act 2022 legislation.gov.uk
Construction (Design and Management) Regulations 2015 legislation.gov.uk
Building Regulations 2010 legislation.gov.uk

Asked most often

The follow-up questions.

The other end of the same discipline is in Gateway 2 and the golden thread.

What is an O&M manual?+

The operation and maintenance manual is the document a building owner uses to run the building after the contractor has gone. It typically carries a description of the works, as-built drawings, plant and equipment schedules, operating instructions, planned maintenance requirements, test and commissioning results, statutory certificates, warranties, and supplier contacts. A useful test: could a caretaker with a leaking valve find out what it is, how to isolate it and who to ring.

Is the O&M manual the same as the health and safety file?+

No, though they are often bound together. The health and safety file, required by CDM 2015 where there is more than one contractor, tells anyone carrying out future construction work what they need to do it safely: residual hazards, structural principles, buried services. The O&M manual tells the occupier how to run the building. One is for the next builder, the other for the current caretaker.

Who is responsible for producing the O&M manual?+

Normally the main contractor, compiling contributions from subcontractors and suppliers, with the specification setting the required contents. In practice it falls between the project manager who has moved to the next job and the commercial team who want retention released, which is a large part of why it is late.

When should you start compiling it?+

At the start of the job, as a file that fills itself, rather than at the end as a document to be written. Every item in a manual existed on site, correct and available, at some point during the works. Filing each one when it is issued is the same total work done once, by the person who knows the answer. The fortnight at the end is what deferring it costs.

Does the O&M manual affect payment?+

Frequently, yes. On many contracts it is a condition of practical completion, or of releasing the first half of retention, or both. A manual two weeks late is two weeks of retention held, and retention held is the money most often never collected at all.

What does the golden thread mean for handover?+

For higher-risk buildings the Building Safety Act requires building safety information to be held digitally, kept accurate and handed on in a form the next duty holder can use. A box of paper does not satisfy it, and nor does a folder of scanned PDFs with no structure. The effect reaches beyond in-scope buildings because clients commissioning both kinds of work increasingly specify the same standard on everything.