Gateway 3: the completion evidence, as-built verification and rebuilding the record before you apply

Gateway 2 gets the attention because it stops you starting. Gateway 3 is the one that stops you finishing, and it is harder to pass, because by then the evidence either exists or it does not. The completion certificate application for a higher-risk building is a reconciliation: it asks you to prove that the building as built is the building that was approved, and it is decided on the record you kept while you were building it. When that record has gaps, the work does not fail at the gateway. It fails weeks earlier, on site, the first time someone asks for an inspection that was never done.

What Gateway 3 actually decides

The completion certificate is applied for under the Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, SI 2023/909, regulations 40 to 45. The principal contractor and principal designer each sign a declaration that, so far as they are aware, the building work complies with all applicable requirements of the Building Regulations, and the client applies to the Building Safety Regulator for the certificate. The regulator decides whether it is satisfied the work complies, and it can ask for more information before it does. Section 76 of the Building Safety Act 2022 is the sanction that makes this gateway real: a higher-risk building, or a part of one, cannot be occupied until the completion certificate for it has been issued. A handover date that assumes the certificate is the difference between a programme that lands and one that slips into dispute.

The record is the application

A declaration that the work complies is only worth the evidence behind it. The golden thread, kept to regulation 31 of the Building Regulations 2010, is where that evidence lives: the information that shows how the building was designed and built to comply, held digitally, kept current and handed over. Gateway 3 reads the as-built version of it. The approved design from Gateway 2 is the baseline; the completion evidence has to show what was actually installed, where it departs from that baseline, and why each departure is still compliant. Underneath the declarations sit the records that prove the point one element at a time: the inspection and test plans with their hold points signed off, the regulation 7 record that the materials and workmanship were adequate and that materials were as specified, and the regulation 38 fire safety information that passes to the responsible person at completion. The application is not a new document you write at the end. It is the filing system you either kept or did not.

Why the record usually has to be rebuilt

On a project that reaches an advanced stage without a structured quality regime, the record is rarely complete, and the problem is worst exactly where it matters most. Work has been covered: risers closed, ceilings boarded, shafts lined, with no inspection evidence captured before it disappeared. Installations have been changed on site to suit a clash or a late substitution, and the change never reached the designer. Subcontractors have certified their own work in formats that do not tie back to a drawing or a compartment line. None of that is unusual, and none of it is fatal, but it does mean the honest first step is not to write the completion pack. It is to find out what can still be evidenced, what has to be re-inspected, and what has to be opened up to be verified at all. A gap assessment that sizes the recoverable and the unrecoverable is worth more at that point than any template.

As-built verification and design reconciliation

As-built verification is the discipline of recording what was actually constructed and reconciling it against the approved design, element by element and system by system. Where the installed condition matches the design, the evidence is captured and the line is closed. Where it does not, the departure is not quietly redrawn; it is assessed as a change. Under SI 2023/909 regulations 18 to 26 a change to the approved design is at least recordable, a notifiable change is notified before it is carried out, and a major change is applied for and not carried out until approved. A departure discovered during as-built verification is caught by the same classification: the designer reviews it, decides whether the as-built condition is acceptable or has to be remedied, updates the design where it is accepted, and the verification then confirms the final position. Done properly it is an iterative loop, design to site to design, and the as-built information and the supporting design end up saying the same thing. Done badly it is a set of red-pen mark-ups nobody signed.

The fire-critical evidence comes first

Not all of the record carries the same weight, and a sensible recovery strategy triages it. Compartmentation, passive fire protection, cavity barriers, fire-stopping at service penetrations, fire doors and the life-safety installations are where the regulator's attention is, because they are what the higher-risk regime exists to control. For these elements the evidence has to be specific: the product actually installed, its assessed classification for the construction it sits in, the inspection that confirmed it was installed to that assessment, and a photograph or a record taken before it was concealed. "Fire-stopping by specialist, certificate to follow" is not evidence; the product substituted for the one assessed is a change, not a detail. Where fire-critical work has already been closed without that evidence, targeted intrusive verification, opening up a representative sample and inspecting it, is usually faster and more credible than arguing that the absence of a record is the same as compliance.

How to structure it so it survives the reading

A completion evidence register that a regulator can follow is structured the way the building is: by building, by floor, by location and by system, with every record traceable to the relevant building element, the drawing and its revision, and the applicable requirement. That structure is what lets a reviewer pull any thread, a compartment line, a riser, a plant room, and find the inspection, the as-built confirmation, the materials record and the design reference without being handed a folder and a wish of luck. It is also what lets the contractor see the gaps while there is still time to close them, because an empty cell in a register organised by location is a site instruction, not a surprise at the gateway. Inspection apps such as Field View hold this well when they are set up to that structure from the start, with the controlled output feeding the document management system the application is assembled from.

Where this leaves you

If you are approaching Gateway 3 on a higher-risk building and the record is not what it should be, the recoverable position is almost always better than it feels, but only if the recovery is run as a process rather than a scramble. Establish the framework and the registers, size the gap, triage the fire-critical evidence, verify the as-built against the approved design, reconcile the departures through change control, and recover or re-create the inspection evidence element by element. That is the work. The completion certificate is what falls out of it.

England only; Wales, Scotland and Northern Ireland have different regimes. This is a summary of the regulations as read on 16 September 2026 and is not legal advice; the Building Safety Regulator's current guidance and the text of the regulations govern.