Understanding the RIBA Stages of Work: A Guide for Homeowners Planning a Building Project
Updated: January 2026
If you’re considering a building project - whether a home extension, refurbishment, or even a new build, you’ve probably come across architects mentioning “RIBA stages” as part of the process. But what does this actually mean? And why is it important for your project?
The RIBA (Royal Institute of British Architects) Plan of Work is the industry-standard framework that architects use to guide projects from concept to completion. It breaks the process down into clear stages, ensuring that every aspect of your project is carefully considered and managed. This structure helps keep things organised and avoids costly mistakes.
The RIBA Plan of Work
At Nancy Gouldstone Architects, we follow the RIBA framework but simplify it into three distinct NGA Stages (A, B, C and D) that align more naturally with residential projects. We also find that for most people it is easier to understand these four stages as they relate to clearly identifiable deliverables in the process whereas the RIBA framework can be difficult for homeowners to engage with. These NGA stages reflect the key phases homeowners typically experience:
Stage A: A1 - Feasibility Study + A2 - Survey & Concept Design
(RIBA Stages 0–2)
Working out what you need - your budget, timeline and design vision and creating an outline design for your home
Stage B: B1 - Design development + B2: Planning & Listed building consent
(RIBA Stage 3)
Resolving the indicative design and getting your permissions in place (Planning, Listed Building Consent, Freeholder consent, Estate consent)
Stage C: C1 Technical Design & Building regulations + C2 Tender & Contract - A resolved, technically detailed set of information of the specifics for the project. Creating a package for the builder to quote from, getting quotes, value engineering to get the project to the right price, and contract administration before construction begins with signing the contract between you and the builder
(RIBA Stage 4)
Choosing the actual specifics for your project so that it can be quoted for accurately by builders and be ready to start building from on site at the next stage. Getting Building Control approval on the technical design.
Stage D: Construction & Delivery & Completion (RIBA Stages 5–6) – Managing the build, overseeing quality on-site, and ensuring a smooth handover.
(RIBA Stage 5)
Building the project on site, ensuring it is doing really well and getting everything finished up so that you can move into your home
This structure provides clarity for our clients, ensuring a clear journey from first ideas to moving into your finished home. Below, we break down how the traditional RIBA stages fit within our streamlined approach.
The RIBA Plan of Work
(and How It Relates to NGA Stages)
RIBA Stage 0: Strategic Definition
(NGA Stage A1 – Feasibility Study)
Stage 0 is the Strategic Definition stage, and its purpose is to establish whether a proposed building project makes sense, why the project should happen and whether it is viable before design begins.
Before any design work begins, we define the project’s objectives and constraints. This includes understanding what you want to achieve whether it’s adding space, improving natural light, or maximising your home’s value. You tell us what your budget is for the construction works and we provide a high level cost for how much similar projects have been built for recently. We explain to our clients that VAT is applicable on projects so that they can factor this into their plan. We listen to the timeframes that you are hoping or need to achieve and we advise on how they can be reached. We will be honest and let you know if the timeframes or the budget you advise upon are broadly realistic based on our experience of similar projects.
We also assess feasibility, potential planning constraints, listed building constraints, Freeholder constraints and Estate constraints (Crown estate, Grosvenor estate etc)and whether additional surveys or reports are required. If planning permission is required, we identify key considerations early on that will need to be factored into the design.
We’ll listen and look at the design vision ideas you have and start to compile a set of precedent reference images to define the aesthetic vision for the project.
Stage 0 sets the strategic foundation for the project team, ensuring the project is a sound proposition before moving forward into detailed briefing and starting the sketch design.
This stage of the work, would always be addressed in our Feasibility Study, the essential first step of every project.
From the RIBA Chart:
RIBA Stage 0 - Strategic Definition
Stage Outcome at the end of the stage
The best means of achieving the Client Requirements confirmed.
If the outcome determines that a building is the best means of achieving the Client Requirements, the client proceeds to Stage 1.Core Tasks during the stage
Prepare Client Requirements.
Develop Business Case for feasible options including review of Project Risks and Project Budget.
Ratify option that best delivers Client Requirements.
Review Feedback from previous projects.
Undertake Site Appraisals.Core Statutory Processes during the stage
Strategic appraisal of Planning considerations.
RIBA Stage 1 Preparation and Briefing
(NGA Stages A1 Feasibility)
RIBA Stage 1, like Stage 0, is fully accounted for within the NGA Stage A Feasibility Study where we define all of the constraints and parameters for your project before the design begins. We craft a Client Brief that becomes the linch pin for the whole process of your design and construction journey, ensuring everything can unfold in a logical and realistic way.
From the RIBA Plan of Work - exact wording:
Stage Outcome at the end of the stage
Project Brief approved by the client and confirmed that it can be accommodated on the site.Core Tasks during the stage
Prepare Project Brief including Project Outcomes and Sustainability Outcomes, Quality Aspirations and Spatial Requirements.
Undertake Feasibility Studies.
Agree Project Budget.
Review Feedback from previous projects.
Source Site Information including Site Surveys.
Prepare Project Programme.
Prepare Project Execution Plan.Core Statutory Processes during the stage
Source pre application Planning Advice.
Initiate collation of health and safety Pre construction Information.
Ashdown Forest house - Developed Design (NGA Stage C, RIBA stages 3)
RIBA Stage 2: Concept Design (NGA Stage A1 - Feasibility + A2 –Survey & Concept Design)
Now, the design process begins. This is where your ideas start to take shape. We explore different design options, considering your requirements, site constraints, and planning policies. At the NGA Stage A1 - Feasibility stage, we will created zoned diagrams setting out the options for how the house can be designed and where functional areas can be located. We’ll zone the areas where your future home can be located on a site and indicate approvable massing and volumes, for existing homes, we’ll indicated what size and where extensions can realistically be located. We’ll map on sun diagrams so you can understand where the light will fall throughout the day allowing us to advise on the best positioning of key areas.
At the NGA Stage A2 - Concept design stage - a measured survey of your property or topographical survey of your site will be commissioned and a 3d model of your home/ site will be produced so that there is an accurate set of base plans and information to work from. We work closely with you to develop a clear brief, outlining your needs, budget, and design preferences. We will take the zoned diagram plans which had defined the usage locations of the project from the Feasibility Study and develop them into a set of functional floor plans. At this stage the design will be outline, making sure we can move quickly to establish an overall, realistic layout for the whole house or apartment. Door locations, circulation spaces and block level designs showing outline massing for kitchens, bathrooms, bedrooms and other rooms will be indicated.
We’ll further refine the cost analysis and provide a more refined programme indicating the duration of the project on the basis of the concept design agreed upon.
By the end of this stage, you will have a developed concept supported by outline design floor plans, along with an outlin cost and timeline estimate.
The RIBA Plan exact wording:
RIBA Stage 2 Concept Design
Stage Outcome at the end of the stage
Architectural Concept approved by the client and aligned to the Project Brief.
The brief remains live during Stage 2 and is developed in response to the Architectural Concept.Core Tasks during the stage
Prepare Architectural Concept incorporating Strategic Engineering requirements and aligned to Cost Plan, Project Strategies and Outline Specification.
Agree Project Brief Derogations.
Undertake Design Reviews with client and Project Stakeholders.
Prepare stage Design Programme.Core Statutory Processes during the stage
Obtain pre application Planning Advice.
Agree route to Building Regulations compliance.
Option: submit outline Planning Application.
RIBA Stage 3: Spatial Coordination
(NGA Stage B1 – Developed design & NGA Stage B2 Consents)
At this stage NGA Stage B1 - Design development, the concept design starts to be brought to life in a much more resolved way. We create a resolved and realistic outline design scheme. Indicative joinery design is added into the plans, indicative ideas for theflooring design will be shown on the plans showing which areas are timber or tiled and indicative outline designs such as lighting, furniture and bathroom and kitchen layouts will be developed. Indicative designs for the exterior of your building will be developed and broadly mapped out. Internally, the design will now consider in detail, how the exact circulation distances work, allowing for joinery and clearances to be assessed.
If planning permission or listed building consent is required, we prepare and submit the application, liaising with the local authority.. During the planning stage depending the project’s requirements, a higher level of detail may be required with details such as windows, doors and materials needing to be specified to a level suitable for technical design (the next stage). Likewise for some listed building consents, at the Pre Application stage, the conservation officer may request specific techinical details, which we will ensure are included for the Listed Building Consent application.
Depending on the exact requirements of your Freeholder or Estate, we will assist with guiding this process and producing all information necessary so that these consents can be efficiently resolved and obtained.
Outcome
A coordinated design that is resolved in principle and ready for technical design.
From the RIBA Plan - Exact wording:
3 Spatial Coordination
Stage Outcome at the end of the stage
Architectural and engineering information Spatially Coordinated.Core Tasks during the stage
Undertake Design Studies, Engineering Analysis and Cost Exercises to test Architectural Concept resulting in Spatially Coordinated design aligned to updated Cost Plan, Project Strategies and Outline Specification.
Initiate Change Control Procedures.
Prepare stage Design Programme.Core Statutory Processes during the stage
Review design against Building Regulations.
Prepare and submit Planning Application.
See Planning Note for guidance on submitting a Planning Application earlier than at end of Stage 3.
RIBA Stage 4: Technical Design
(NGA Stage C1 – Technical Design & Stage C2 - Tender & Contract)
This is where your project becomes fully detailed and ready for construction. At the NGA Stage C1-Technical Design - we prepare comprehensive technical drawings and specifications of your home for building regulations compliance as well as producing the information to a level that builders will be able to realistically quote for the full project with as fixed fee as possible. If appointed as the Contract Administrator and Quantity Surveyor, We would undertake NGA Stage C2- Tender & Contract - and would include the tendering process where the works are defined in an excel format ‘Schedule of works’ along with a full pack of the relevant drawings and specifications and are sent out as a competitive tender for contractors to price from. Once a contractor has been chosen, a contract package would be produced, which sets out roles, responsibilities, we would advise on the most suitable contract to use and would execute it so you can the builder sign the project together before the work starts on site.
Our Brompton Townhouse project - At the Detail Design stage - RIBA Stage 04, items such as the exact bricks are chosen, the exact design of the windows and doors and the choice of floor tiles, joinery and lighting specification
From the RIBA Plan - exact wording
4 Technical Design
Stage Outcome at the end of the stage
All design information required to manufacture and construct the project completed.
Stage 4 will overlap with Stage 5 on most projects.Core Tasks during the stage
Develop architectural and engineering technical design.
Prepare and coordinate design team Building Systems information.
Prepare and integrate specialist subcontractor Building Systems information.
Prepare stage Design Programme.Specialist subcontractor designs are progressed and reviewed during Stage 4.
Core Statutory Processes during the stage
Submit Building Regulations Application.
Discharge pre commencement Planning Conditions.
Prepare Construction Phase Plan.
Submit form F10 to HSE if applicable.
RIBA Stage 5: Construction
(NGA Stage D – Construction, Delivery & Handover)
With a contractor appointed, the project moves on-site. As your architect, we remain involved to oversee the construction, answer queries, and ensure the design intent is followed. Regular site visits and meetings keep the project on track, and we assist in resolving any unforeseen issues. If required, we can also act as the Contract Administrator and Quantity Surveyor for the site stage.
Purpose
To construct the building in accordance with the contract and technical design.
What happens at this stage
Construction works are carried out on site
Architect administers the building contract (where appointed)
Site inspections and quality monitoring
Design queries and variations are managed
Progress and payments are certified
From the RIBA Plan of Work - exact wording:
5 Manufacturing and Construction
Stage Outcome at the end of the stage
Manufacturing, construction and Commissioning completed.
There is no design work in Stage 5 other than responding to Site Queries.Core Tasks during the stage
Finalise Site Logistics.
Manufacture Building Systems and construct building.
Monitor progress against Construction Programme.
Inspect Construction Quality.
Resolve Site Queries as required.
Undertake Commissioning of building.
Prepare Building Manual.Building handover tasks bridge Stages 5 and 6 as set out in the Plan for Use Strategy.
Core Statutory Processes during the stage
Carry out Construction Phase Plan.
Comply with Planning Conditions related to construction.
Our Georgian Listed Townhouse, completed after a full back to brick reconstruction and refurbishment
RIBA Stage 6: Handover and Close-Out
(NGA Stage D – Construction, Delivery & Handover)
The project reaches completion, and you move into your newly finished space. We conduct final inspections, address any snagging, and provide all necessary documentation, including warranties and maintenance guidance.
Purpose
To complete the project and hand it over to the client.
What happens at this stage
Practical completion and handover
Resolution of defects
Final inspections and certifications
Building manuals and information are provided
Outcome
The building is formally handed over and ready for occupation.
From the RIBA Plan of Work - exact wording:
6 Handover
Stage Outcome at the end of the stage
Building handed over, Aftercare initiated and Building Contract concluded.Core Tasks during the stage
Hand over building in line with Plan for Use Strategy.
Undertake review of Project Performance.
Undertake seasonal Commissioning.
Rectify defects.
Complete initial Aftercare tasks including light touch Post Occupancy Evaluation.Core Statutory Processes during the stage
Comply with Planning Conditions as required.
RIBA Stage 7: In Use (NGA Stage G - Retention Period)
Although construction is complete, this stage is about the long-term performance of your home and the period stated within the contract called the ‘Retention’ period of ‘Latent defects period’. The retention period ensures that any final contractor obligations are fulfilled.This is usually set at 6 months or 12 months depending on the complexity or size of the project. This allows for the project to settle and for any hidden or ‘latent’ defects to become evident, things like leaking plumbing or electrical items or plasterwork that has moved. During this period, the contract has an obligation under the contract to remedy any defects (not wear and tear). At the end of the 12 months, the contractor will be due their retention sum which relates to 2.5% of the contract value back once they have fixed all defects to the satisfaction of the contract administrator and architect. After this point the Final Completion certificate is issued.
Purpose
To review the building in use and support the client post-completion.
What happens at this stage
Post-occupancy evaluation (where included)
Review of building performance
Feedback gathered to inform future projects
Outcome
Understanding of how the building performs in use.
From the RIBA Plan - exact wording:
7 Use
Stage Outcome at the end of the stage
Building used, operated and maintained efficiently.
Stage 7 starts concurrently with Stage 6 and lasts for the life of the building.Core Tasks during the stage
Implement Facilities Management and Asset Management.
Undertake Post Occupancy Evaluation of building performance in use.
Verify Project Outcomes including Sustainability Outcomes.Core Statutory Processes during the stage
Comply with Planning Conditions as required.
Adaptation of a building at the end of its useful life triggers a new Stage 0.
Why we use NGA Stages (A, B, C,D) for residential projects
While the RIBA Stages provide an excellent framework, we find that breaking it down into three clear NGA Stages helps homeowners better understand the journey:
(NGA Stage A)Defining your brief, creating a feasibility study and preparing a concept design(Stage A): All feasibility, concept design work
(NGA Stage B) Developing the design and achieving planning, listed building and freeholder consent:
(NGA Stage C) Technical Design & Building control Compliance, Tender 7 Contract : Everything needed to finalise and refine the design and then work up the technical details, obtain statutory approvals, and prepare for construction.
(NGA Stage D) Construction, Delvery & Completion : Administrating the build, ensuring quality, and handover.
By structuring our process this way, we make it easier for clients to see what’s coming next, when key decisions need to be made, and how different phases of their project interconnect.
Why choose a chartered RIBA practice?
As a RIBA chartered practice, Nancy Gouldstone Architects adheres to the highest professional standards set by the Royal Institute of British Architects. This means we follow rigorous codes of conduct, maintain continual professional development, and ensure our designs meet best-practice guidelines. Working with a RIBA-accredited firm provides you with confidence in the quality, expertise, and integrity of our service - ensuring that every stage of your project is managed with precision and care.
Why the RIBA stages matter
Understanding the RIBA stages helps demystify the process and gives you confidence in how your project will be managed. It ensures a logical progression from ideas to a finished building, with clear milestones along the way. By following this structured approach, we can minimise risks, control costs, and deliver a beautifully designed space tailored to your needs.
If you’re planning a project and would like to discuss how we can guide you through the RIBA stages, feel free to get in touch. We’d be happy to help bring your vision to life with a well-structured and professionally managed process.
We have also created a post on how to apply the following stages in relation to planning your own London building project - a step by step easy guide.