RIBA Stage 4: What Technical Design Must Cover Before Tender

What is RIBA Stage 4 and what does it have to deliver?

RIBA Stage 4 is the Technical Design stage of the RIBA Plan of Work 2020. Its outcome is that all design information required to manufacture and construct the project is completed, and its core task is to develop the architectural and engineering technical design.

That is the plain statement in the RIBA Plan of Work 2020 overview. Everything else in this guide expands on the word "completed". At the end of Stage 3 the design is spatially coordinated and the planning application has been submitted. At the end of Stage 4 it must be buildable, which means that a contractor can price it, a building control body can assess it and a specialist can detail within it.

The Plan of Work lists the stage outputs as the manufacturing information and construction information, the final specifications, the updated cost plan and the bills of quantities or pricing schedules, as defined by the procurement strategy. It also lists the core statutory processes that fall in this stage: reviewing the design against the Building Regulations, submitting the Building Regulations application, discharging pre-commencement planning conditions, preparing the construction phase plan and submitting an F10 notification to the HSE where applicable.

Two features of the stage matter to a technical director more than the headline. First, the Plan of Work says Stages 4 and 5 overlap on most projects. The design is rarely finished on the day the contractor starts, so the question is what has to be complete before tender and what can legitimately follow. Second, the Plan of Work expects a signed-off Stage Report to be unusual at the end of Stage 4, although some clients ask for one to record decisions. In the absence of a report, the pre-issue review is the formal moment at which the practice says the information is fit to issue.

A framework, not a contract

The stages describe a typical sequence. They do not decide what an appointment includes. The scope of the architect's Stage 4 services is whatever the appointment says, which may stop before construction information is complete if the contractor is to produce it. The first task is therefore to read the appointment and the procurement route, and to write down which of the Stage 4 outputs this practice is responsible for. The project programme and RIBA stages guide covers how that sits in the programme.

What must be complete before the project goes to tender?

Eight areas must be complete or deliberately deferred: drawings, specification, schedules, coordination, design responsibility, building regulations and planning, cost and procurement, and health, safety and handover. Each has a test a technical director can apply without reading every sheet.

The table is a gate, not a shopping list. Each row is there because incomplete information in that area is routinely found at tender. Three deserve a closer look.

Drawings and schedules that agree

Contradictions between drawings, schedules and the specification are the commonest defect found at contract issue, and the cause is how the documents are made, not carelessness. Different people update them on different days. The answer at Stage 4 is to decide, element by element, which document is the source of each value and which refer to it. A door's fire rating lives in the door schedule, the plan carries only the tag, and the specification clause refers to the schedule instead of repeating the number. The defects guide gives the figures.

Specification that is final, not near-final

The RIBA term is "Final Specifications", and the word final is meant. A specification with open TBCs at issue transfers decisions to the contractor's price or to a later claim. TBCs in Specifications at Tender explains the consequences. Before Stage 4 begins, the outline specification from Stage 2 and 3 should already name the systems and performance drivers. Technical design turns that into project-specific clauses, which is covered in the outline specification guide.

Design responsibility assigned before tender

The Responsibility Matrix is listed in the Plan of Work as an input to Stage 4. By tender it should be aligned with the specification and the contract documents, so that every contractor's design portion has a brief the tenderers can price. See the design responsibility matrix guide and the guide to contractor-designed portions.

How does the procurement route change Stage 4?

The procurement route decides when each building system is designed and by whom. On a traditional contract the design team completes most of the design before tender and specialists finish their portions after award. On a design-and-build contract, Stage 4 may be shared between the original design team and the contractor's team.

The RIBA Plan of Work says the procurement strategy influences when building systems will be designed, dictating the structure of the Stage 4 design programme. It may require Stage 4 to be undertaken in two parts, and it may change who is on the team, as when the design team is novated to the contractor. Two arrangements cover most cases.

Defining the cut-off

Whichever route applies, the project needs a written statement of what the design team will have completed at the point of tender or novation. Three questions settle most of it. Which systems are prescribed in full, and which are described by performance? Which interfaces are resolved by the design team, and which are left to the specialists to resolve? Which statutory submissions will be made before award, and which after? Putting the answers in the matrix and the preliminaries removes the later argument over whether information was incomplete.

Overlap with Stage 5

Because Stages 4 and 5 overlap, the practice needs a method for design information that is issued after tender. Every later issue should be traceable to a reason: the specialist's detail design, a client change, an unforeseen condition, a building control comment. The note on specification change control covers how to record that.

What do building regulations, planning conditions and Gateway 2 add at Stage 4?

Stage 4 is where statutory submissions are completed. The design is checked against the Building Regulations, a Building Regulations application is made, pre-commencement planning conditions are discharged and, for a higher-risk building in England, the Gateway 2 application must be approved before construction work starts.

For a building that is not higher-risk, the Building Regulations application is made to a building control body, either the local authority or a registered approved inspector, and the route is a full plans application or a building notice where permitted. The architect's task at Stage 4 is to make sure the information that goes to building control agrees with the information that goes to tender. A building control comment that changes the design after tender is expensive. A comment that reveals the drawings and the specification disagree is more so.

Planning conditions

The Plan of Work lists discharging pre-commencement planning conditions and preparing the supplementary information needed, such as large-scale details. The conditions list should be included in the tender information so that the contractor prices the effect of each. For a practical approach see the guide to discharging planning conditions.

Higher-risk buildings and Gateway 2

Under the Building Safety Act 2022 and the Building Regulations etc. (Amendment) (England) Regulations 2023, a higher-risk building is subject to a gateway regime administered by the Building Safety Regulator. Gateway 2 is the building control approval application, made before construction work starts. Approval is needed before the work begins, so the technical design on a higher-risk building has to be mature enough to satisfy the regulator at the point the application is made. The application includes, among other things, plans and a fire and emergency file, and the construction control plan and change control plan that set out how compliance will be managed and how changes will be handled. Check the current Building Safety Regulator guidance for the full list of application contents.

In practice this pulls a good deal of Stage 4 work forward. Specification, coordination and design responsibility must be in place when the application is made, not at tender. The consequence is that the pre-issue review has to take place before the Gateway 2 submission as well as before tender. The Gateway 2 submissions guide, the higher-risk buildings guide and the specification and Gateway 2 guide cover this, and the golden thread guide explains how the information must be kept.

Fire safety and the technical standards

The Plan of Work expects the fire safety design to be closed out by the end of Stage 4, addressing Parts A, B and M and Regulation 7. That means the fire strategy has to flow into the drawings, the schedules and the specification without contradiction. The fire strategy report guide and the Approved Document B guide give detail. Energy and ventilation provisions (Parts F, G and L) also belong in the checked information, as the Plan of Work notes for sustainability. See the Part L guide.

How does Stage 4 end, and what leads into the pre-issue review?

Stage 4 for the architect ends with an information exchange that the Plan of Work describes lightly: a signed-off stage report is optional, and the practical test is whether the issue set can survive a comparison review. The pre-issue technical review is that test.

The Plan of Work lists the Responsibility Matrix, the information requirements and the Stage 4 design programme as inputs, and the completed technical design as the output. It does not tell you how to know the output is complete. That is the technical director's job, and it is easier with a defined sequence.

The review itself is set out in the pre-issue technical review checklist. It follows seven checks in a fixed order: identity, extent, performance, references, standards status, decisions and responsibility. The review should be carried out by someone who did not write the specification, ideally the technical director or a delegate, and the result recorded.

What to do when Stage 4 cannot be completed

Sometimes the programme forces issue before the design is complete. Treat that as a decision, not an accident. List the elements that are incomplete, say why, state what the tenderers should assume, and mark them as provisional in the documents. A provisional sum with a stated scope is a controlled risk. A silent gap is an uncontrolled one.

An incomplete issue is acceptable if it is declared. It is a problem when the practice discovers that it was incomplete only after the tender returns.

Questions technical directors ask about RIBA Stage 4

What is RIBA Stage 4?

Stage 4 is Technical Design in the RIBA Plan of Work 2020. Its outcome is that all design information required to manufacture and construct the project is completed. The core task is to develop the architectural and engineering technical design, and the outputs include final specifications, manufacturing and construction information, and the updated cost plan.

What is the difference between RIBA Stage 3 and Stage 4?

Stage 3 produces spatially coordinated architectural and engineering information and ends with the planning submission and a stage report. Stage 4 turns that into information that can be manufactured and built, including final specifications and the Building Regulations application.

Does the architect complete all of Stage 4 before tender?

Not always. On a traditional contract with contractor's design portions, specialists complete their designs after award, and on design and build the contractor may complete technical design. The Plan of Work notes that the procurement strategy may require Stage 4 in two parts.

What does RIBA Stage 4 include for higher-risk buildings?

The Gateway 2 building control approval application, made to the Building Safety Regulator, must be approved before construction work starts. The technical design, specification and design responsibility need to be mature enough at the point of that application.

When do Stage 4 and Stage 5 overlap?

On most projects. The Plan of Work notes that Stages 4 and 5 overlap in the programme, because specialist design and queries continue after the contractor starts on site.

What should be checked before Stage 4 information is issued?

Drawings, schedules and specification should be compared for identity, extent, performance, references, standards status, open decisions and design responsibility. The pre-issue technical review records that comparison and the sign-off.

Where Avoice fits

Stage 4 is the stage where documents have to agree with each other, which is the work Avoice is built to hold in place.

The office master gives the practice a governed starting point, so that technical design starts from clauses the practice has already agreed, not from the last job. Practice Rules apply the values, standards and wording the practice requires while the specification is written. The pre-issue Technical Review compares the specification with the schedules and drawings, and the clause library and schedules keep repeated values in one place. For higher-risk buildings, the Compliance module tracks Building Regulations requirements, planning conditions, the CDM risk register and principal designer duties, supports Gateway 2 preparation and keeps the golden thread in the Project Record. BIM integration with Revit and ArchiCAD supports the link between model and specification.

Avoice does not decide what is complete. The technical director sets the cut-off, the practice sets the standard, and the review is signed by a person.