Last edited 16 Nov 2018

Developed design

The process of completing the design and construction of a building is often divided into notional 'stages'. This can be helpful in establishing milestones for the submission of progress reports, the preparation of information for approval, client gateways, and for making payments.

However, there is a great deal of ambiguity between the naming of stages and the definition of what individual stages include (for example, see Comparison of work stages), and so it is important that appointment documents make it clear what activities fall within which stage, and what level of detail is required.

'Developed design' is a phrase coined by the Royal Institute of British Architects (RIBA) for their 2013 Plan of Work. This plan comprises eight work stages, and its new terminology, stage referencing system and lack of detail have generated some criticism.

The invention of term 'developed design' in particular, is, rather peculiarly, in the past tense (unlike any other stage names), implying that the stage is complete, and it means little to clients or to the wider industry.

The RIBA states that 'Developed Design maps broadly to the former Stage D – Design Development – and part of Stage E – Technical Design. The strategic difference is that in the RIBA Plan of Work 2013 the Developed Design will be coordinated and aligned with the Cost Information by the end of Stage 3. This may not increase the amount of design work required, but extra time will be needed to review information and implement any changes that arise from comments made before all the outputs are coordinated prior to the Information Exchange at the end of Stage 3.'

It is not clear why the design and cost were not aligned in previous versions of the plan of work, or which elements of technical design this stage now includes.

The RIBA describe the activities carried out during the stage as preparing the 'developed design, including co-ordinated and updated proposals for structural design, building services systems, outline specifications, cost information and project strategies in accordance with the design programme.' Spatial coordination should be completed and change control procedures introduced, and typically landscape designs will be prepared and planning applications made. This stage may involve input from specialist sub-contractors and suppliers.

Historically, the tasks associated with 'developed design' would have been described as the 'detailed design' stage, which is perhaps a clearer and better understood description.

Where building information modelling (BIM) is being used, during this stage, the project information model is developed based upon generic representations with approximate quantities, size, shape, location, tolerances, and so on. Specification properties and attributes are developed so that the selection of systems and products is possible.

Where the employer has already specified that certain building products should be used, or where there are key components that have already been selected, these may be incorporated into the model. Structural information and architectural information should develop in detail, and services design may include generic information about sizes, capacity and control systems. The model may allow early contractor engagement and an outline construction sequence may be developed. Plans, cross sections, elevations, and visualisations may be produced as well as schedules of facilities.