Detailed structural design is the stage where the design of a building is refined and plans, specifications and estimates are created. It is the stage where the full cost of the project is identified and often includes outputs like 2D and 3D models, build up estimates, procurement plans and others. It involves the process of taking on and developing the approved concept.

The detailed design stage describes all structural parts completely and precisely and how they fit together. It investigates the stability, strength, and rigidity of the structure in respect of the physical requirements of the building. It serves as the basis for the construction phase and it allows for appropriate adjustment of the entire project cost. It ensures that the design solution satisfies the objectives of the project.

Hence, the basic reason for detailed design is to develop the initial sketch plan design into more detailed building documentation which provides sufficient information for applications for statutory approval to be made.

It is to produce an efficient structural system, capable of resisting specified applied loads without failure during its intended lifecycle. The design should determine the most suitable proportions, dimensions and details of the structural elements and connections.

Components of Detailed Design

The following components must be included in the complete detailed design.

• Overall layout
• Road layouts and landscape
• Operational flows and departmental operational policies
• Horizontal and vertical circulation routes, including accessibility requirements
• Schedules of accommodation, including occupancy numbers for each space
• 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. These include: block plans, site plans and external works, changes in floor levels, expansion joints, demarcation of changes to finishes, and reflected ceiling plans
• 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. Designers should investigate suppliers certificates, warranties and compliance with standards.
• Requirements for mock-ups, testing, samples or models necessary to satisfy performance or public relations requirements.
• Key assemblies, component drawings and schedules with special attention to junctions and interfaces between elements which will influence the structural or services designs or have an effect on the spatial allowances. Key details will include: External walls, lining, cladding, glazing, windows and blinds, balconies, canopies and entrances, roofing and finishes, rooflights, drainage, gutters and outlets, floor constructions and finishes, staircases, damp proof courses, service duct and services plan enclosures, load bearing internal walls and partitions, including lifts and other shafts, non-load bearing partitions, ceiling construction and support, overall dimensions and fixing details for fixed equipment such as sanitary fittings and joinery, roads, paths, paving, boundaries and retaining walls, and external gradients and falls including gutters and outlets.

Other components include:

• Initial schedules
• Structural plans sections, elevations and specifications
• Building services plans, sections and elevations
• Define phases if the project is to be phased. This can be complicated by items that appear in buildings intended for later phases, but that are required for the operation of earlier phases, for example boilers or escape stairs.
• Safety strategy
• Fire strategy
• Acoustic separation and acoustic conditions (reverberation times etc).
• 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.

Final Words

Detailed design makes detailed building documentation possible, provides sufficient information for statutory approval, and produces an efficient structural system which is capable of resisting specified applied loads without failure during its intended lifecycle.