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Last edited 19 Oct 2022

Building design process

1 Definition
2 The growth of the design team
3 Establishing the need
4 Feasibility Study
5 Selection of designers
6 Concept design
7 Detailed design
8 Production information
9 Ongoing design development
10 Conclusion
11 Related articles on Designing Buildings

[edit] Definition

Building design resolves client requirements into a set of instructions for the construction of a building.

This article provides a summary of a process that, while it varies from project to project and the actual 'creative' part is very difficult to describe, nonetheless tends to follow a series of well-established stages.

The process described is that of a typical, medium-sized commercial project on a traditional procurement route. Smaller or larger projects tend to confront the same questions and follow the same processes, albeit on a different scale, as will projects on other procurement routes, the difference being the nature of the contractual matrix between the client, designers and contractors.

[edit] The growth of the design team

Whilst historically, buildings tended to follow set patterns that could be repeated without a great deal of consideration or instruction, as buildings became more complex, so specialist designers emerged, and increasingly, building design has proved too complex for any one individual to undertake alone, other than on very straight-forward projects.

Today a project may sometimes begin with just one designer, but as the design develops and the level of detail increases, so the design team will tend to grow. A full design team on a typical commercial or residential building project will include a core team of; architect, structural engineer and services engineer(mechanical and electrical engineers) along with other designers as necessary, such as landscape designers, interior designers, and specialists such as acoustic designers, fire engineers, and so on.

Increasingly, contributions are also made by contractors and suppliers, and the design team is supported by experts in health and safety, cost, programme, planning, sustainability, accessibility, project management and so on.

[edit] Establishing the need

The most important question on any project is whether a building is needed at all. Building is an expensive and disruptive undertaking.The client's needs may be able to met by different solutions which may be less expensive and less risky.

Establishing whether a building is needed, and if so, what sort of building, what budget to set and what site to build is a significant piece of work that should not be underestimated or under-resourced. In some cases it can take longer than the design and construction processes, requiring detailed analysis of business needs, staff requirements, client relationships and so on. Even where the question as to whether a building(s) is needed or not can be easily answered (such in a housebuilding project), effort will need to go into clearly articulating the clients project objectives and success criteria,and agreeing any client-set constraints.

In outline, establishing the need for a building involves:

Identifying and describing the business need that might result in the requirement for building works (see statement of need).
Establishing whether there is a business case for setting up a 'project' to investigate the possibility of undertaking building works (see preliminary business case).
Preparing a strategic brief that describes the overall project requirements and significant constraints, focussing on what the project needs to achieve rather than prescribing potential solutions.

Establishing the client's requirements should focus on the functions they need to perform rather than leaping to conclusions by looking at possible solutions. For example, whilst the need to facilitate better communication within a department could be addressed by creating new common spaces where staff can interact, it might be better achieved by regular away days.

Building is not always the right answer, and even if it is, the type of building that best satisfies client's needs might not be the one that initially springs to mind. Leaping to conclusions results in missed opportunities and stifles innovation (see output-based specification for more information).

There can also be conflicting needs (for example ease of access vs security in an airport), and different stakeholders in the project may have different requirements or expectations. In order to run a successful project it is important to address the needs of the projects stakeholders, effectively predicting how the project will affect them and how they can affect the project.

[edit] Feasibility Study

A feasibility study involves researching the physical and legal condition of the land or property being considered for development in order to identify constraints, risks and opportunities, and to obtain a more detailed understanding of the nature and characteristics of the property in question. Typical investigations will include:

structural surveys of existing buildings (if they are expected to be retained and used)
site topography
looking for evidence of underground chambers, voids, tunnels, pipes, watercourses etc
checking with statutory utilities whether any of their infrastructure passes under or over the site
checking with statutory utilities about the capacity of the services supplying the site
a ground investigations report looking at the ground's
- bearing capacity,
- mineral composition
- chemical composition
- presence of flora & fauna (esp protected species / invasive species)
a review of planning policy requirements and their potential impact on site capacity
a review of the surrounding neighbourhood (the site context)

Gathering this information means the project team can come to a much more accurate understanding of the site capacity on the likely acceptable amount and scale of new building that could be constructed, and the estimates of cost and time required will be much more accurate than without this research.

Once the feasibility study has been concluded, the project team can:

identify options, and the preferred option.
produce an updated (and more accurate) financial viability assessment
produce an updated (and more accurate) schedule
gain an improved understanding of the skills needed to successfully deliver the project (and whether the project team can procure)
have an improved understanding of the risks and opportunities that the client will face if they pursue the scheme.

the output of this work will either be a decision that the scheme does not look do-able, and it should therefore be aborted, or a Business Case that outlines the justification for pursuing the scheme.

if the Business Case is approved by the client the Project Manager will prepare a

project execution plan for the preferred option
an initial project design brief

It is very important to stress that none of this involves any design work. Feasibility studies and options appraisals may include diagrams used to assess whether a potential site or building type is possible, but they are not designs. This stage is about identifying the client's requirements, establishing that these requirements are feasible agreeing that the project should proceed in a particular direction.

Depending on the complexity of the project and how experienced the client is, they may need the advice of consultants during this process. A very experienced client, such as a retailer developing a new outlet may have all the expertise they need in-house, whereas a an inexperienced client developing a complex project for the first time may need independent client advisers to help them from the outset and may need progressively to appoint more consultants as it becomes certain that the project will progress.

Designers may be appointed to help assess options for feasibility studies, and to develop the project brief, but no actual design work is involved.

[edit] Selection of designers

Once the nature of the project has been defined, it is possible to appoint designers. These may be different to the consultants appointed to assist the client in the preparation of feasibility studies, options appraisals or brief development.

Designers may be selected on the basis of:

Recommendation, for example, one consultant may recommend others, which can save time for the client and make it easier to establish collaborative practices.
Reputation.
Research and interview.
Open competition (with or without design).
Selective competition (with or without design).
An existing relationship or framework agreement.

See Appointing consultants for more information.

[edit] Concept design

Concept design is the first true design stage. It is the creative response to the project brief for the preferred option.

Whilst concept design may begin with the creative ideas of a single individual, it is an increasingly collaborative process that involves a team of designers and advisers coming together, discussing options, opportunities and constraints, and then separating to carry out more detailed assessment.

Input from other members of the team will be required on cost, safety, buildability, programme, health and safety and so on, as well as consultation with third parties such as the local planning authority. Specialist input may be needed as the concept develops and and so the design team may grow.

During the concept design stage, the consultant team will develop:

The design concept.
Outline specifications.
Schedules of accommodation.
A planning strategy.
The cost plan.
Procurement options.
Programme and phasing strategy.
Buildability and construction logistics.
Constraints and opportunities

The design will tend to be led by the architect (see lead designer), although there are occasionally specialist projects where it may be more appropriate for the design team to be led by another consultant, for example the services engineer on a highly-serviced building.

The creative process itself is an Illusive one, and despite attempts to systematise it, it tends not to follow fixed rules. A very broad description of the design process is one of divergence, assessment and then convergence. A single thought expands into a myriad of possibilities that are developed, assessed and compared, before they are progressively rejected leaving only the optimal solution remaining. This means that much of the work that is undertaken is aborted and it can sometimes seem to clients as if there has been little result for significant expenditure of fees. This feeling can be exacerbated by the fact that creative design tends to be an internal thought process that designers find difficult to express.

Design involves attempting to solve problems that may be only loosely understood at the outset, and solutions are not necessarily been reached by a purely logical process. This can make it difficult for clients to assess proposals objectively, other than by comparing them to the requirements set out in the brief, verifying that designers have considered appropriate issues (see concept architectural design checklist and design quality) and assessing value for money.

To avoid surprises, it is important that the client is fully involved in the concept design process, and that whilst developing the concept, the project brief also evolves as the both the client and the design team come to understand requirements and preferences better. On large projects this may involve identifying a number client 'champions' given responsibility for monitoring the brief and design quality within a specific area of the project. Value management exercises may be necessary where the cost of the evolving design begins to exceed the budget.

At the end of the stage, the consultant team will prepare a concept design report for the client which records the basic design concepts for the preferred option. The concept design report will also identify any instructions required from the client. The project brief should be frozen on approval of the concept design and change control procedures introduced.

An application for planning permission might be made during the concept design stage. This is likely to be an outline planning application if made at the beginning of the stage or a detailed planning application if made once the concept design is complete.

[edit] Detailed design

Detailed design (sometimes referred to as design development or detailed design and technical design) takes on and develops the approved concept design.

By the end of this stage the design should describe all the main components of the building and how they fit together, but the design will not have been packaged for tender (obtaining prices from contractors).

Detailed design should provide sufficient information for applications for statutory approvals, such as building regulations approval, and may include an application for detailed planning permission if this has not already been done. This is likely to require a process of consultation and negotiation with the local authority and other stakeholders and third parties (see third part dependencies).

The completed detailed design should include:

Overall layout.
Road layouts and landscape.
Operational flows.
Horizontal and vertical circulation routes.
Schedules of accommodation.
Identification of standard and non-standard room layouts.
If appropriate, room data sheets.
Building dimensions and gridlines.
Architectural plans sections and elevations of buildings, parts of buildings and components.
Outline specification including schedules of components, defining the performance and/or material standards required (including colours).
Elements of design that require specialist input or early choice of manufacturer.
Requirements for mock-ups, testing, samples or models necessary to satisfy performance or public relations requirements (including computer generated images).
Key assemblies, component drawings and schedules.
Initial schedules of finishes, doors and ironmongery, sanitary fittings, room numbers and signage.
Structural plans sections, elevations and specifications.
Building services plans, sections and elevations.
Definition of phases if the project is to be phased.
Safety strategy.
Fire strategy.
Acoustic separation and acoustic conditions.
The use of materials and the potential for re-use, recycling and waste handling.
Detailed cost plan showing the capital and lifecycle costs for all the components.
Risk assessment including operational issues such as lifts, cleaning of atrium roofs and facade etc.

See Detailed design for more information.

Increasingly, detailed design involves input from specialist designers. These may; be contractors or suppliers appointed in the first instance to carry out design and subsequently to carry out the works on site or to supply goods or services, or appointed by the client to carry out design and then perhaps to monitor works on site, or sub-consultants to a member of the consultant team.

See Specialist designers for more information.

A design co-ordinator might be appointed to ensure proper integration and co-ordination of specialist designs into the overall design.

As with the concept design stage, value management exercises may be necessary where the cost of the evolving design begins to exceed the budget.

A detailed design report should be prepared for approval by the client before proceeding to the next stage.

[edit] Production information

The production information stage is concerned with preparing the information that the contractor(s) will need to construct the project. It should also include the completion of applications for statutory approvals such as building regulations approval. The quality of production information is extremely important. Unless it is prepared and co-ordinated properly, there will be disputes and delays on site, and unecessay costs will be incurred.

Production information may include:

Drawings (location drawings, component drawings and dimensioned diagrams).
Specifications, design criteria and calculations.
Bills of quantities or schedules of work..

Increasingly software is used to prepare elements of production information such as computer aided design (CAD) to prepare drawings and proprietary systems for the preparation of specifications. Recently, building information modelling (BIM) has begun to allow the automatic generation of all elements of production information from a single co-ordinated model, resulting in a reduction in errors and so costs.

At the end of this stage, a production information report should be prepared for the client's approval. This is the last opportunity for the client to consider issues to do with the design of the development before the tender process begins. It may also be the first time that the client has seen drawings describing key components (such as door handles), assemblies and specialist items.

As a result, the client may wish to issue the production information report (or parts of it) for consideration to key users and perhaps to their lawyer or other independent client advisers. Once the main contractor has been appointed, subsequent changes can become very expensive.

[edit] Ongoing design development

When production information is complete, the project can be tendered and a contractor appointed to complete the works.

Design may still be necessary, for example, if it had not been possible to complete the design of every aspect of the building before appointing the contractor, or if the project is constructed in phases. There may also need to be solutions developed to problems that emerge on site.

On different procurement routes, such as construction management, the construction of below ground works such as foundations may begin before the design of the above ground works is complete. However this are inherently risky and may leave the client exposed to additional costs.

Design work also be carried out by the contractor, suppliers and sub-contractors, but this should fall outside of the responsibility of the main design team, unless co-ordination or approval is required.

[edit] Conclusion

In summary, design tends to follow a relatively consistent process of project definition followed by the development of an increasingly detailed solution. Throughout this process, it is vital to be clear who the stakeholders for the new building are and what it is they need, and then to keep focused on satisfying that need. Design itself is then a complex balance of maintaining close control whilst not closing off options too early.

Changes tend to cost more and cause more disruption as design progresses, and there is a tendency for budgets and designs to diverge unless strong management is in place. The actual ‘creative’ part of the process remains remarkably illusive, and within the context of the whole development of a building, may be relatively short.