The process for 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 and so it is important that appointment documents make it clear precisely what activities fall within which stage, and what level of detail is required.
Generally the phrase ‘technical design’ refers to project activities that take place after the detailed design (or ‘developed design‘ or ‘definition’) has been completed, but before the construction contract is tendered or construction begins.
Increasingly however, technical design may continue through the preparation of production information and tender documentation and even during construction itself, particularly where aspects of the technical design are undertaken by specialist subcontractors.
The lead designer co-ordinates the preparation of the technical design. As this may involve design not only by the client’s core design team but also by specialist subcontractors, it may be appropriate to organise a specialist contractors’ start-up meeting at the beginning of the stage. A design responsibility matrix can help allocate design tasks between the project team members, and on complex projects, it may be necessary to appoint a design co-ordinator responsible for co-ordination and integration of different aspects of the technical design.
There is some skill in establishing the order for undertaking technical design. For instance the ceiling tile grid has to be established so that light fittings, sprinkler heads and smoke detectors can be located centre of tiles and access provisions to services in ceiling voids can be established. Similarly, mullion positions for cladding systems dictate partition locations between cellular offices. Drainage set to falls has priority over ceiling pipe work, ductwork and electrical trunking the latter being more flexible in its routing. It is argued by some that co-ordination between the different aspects of this technical design is best carried out by the client’s design team despite the increasing tendency to transfer responsibility to contractors.
By the end of the stage the architectural, structural and mechanical services design and specifications should describe all the main components of the building and how they fit together, any performance specified work should be defined and there should be sufficient information for applications for statutory approval to be completed. Room data sheets are also likely to have been prepared along with outline technical specifications.
Regular reviews should be carried out during the stage to assess construction sequencing, buildability, the interfaces between different elements of the design, the project programme and risk. The client’s design team may be required to review design information prepared by specialists to ensure proper integration into the wider design.
Once the client is satisfied with the technical design, the lead consultant should freeze the design and specifications and introduce change control procedures and remaining statutory approvals and other approvals should be completed.
The principal designer assesses and gives advice about any additional design information that is prepared by the contractor, specialist contractors or specialist designers (including temporary works) and the contractor updates the construction phase plan and re-issues it as required.
Where there are any proposed variations, procedures for their valuation are implemented (as described in the contract). Where changes exceed the delegated authority of the employer’s agent, approval should be requested from the client.
The employer’s agent co-ordinates site inspections, issues instructions as required and assesses any claims for extension of time or loss and/or expense (perhaps with advice from independent client advisers).
The contractor prepares interim applications for payment. The employer’s agent checks applications for payment and issues payment notices to the contractor of the amount to be paid. The notices must be issued within five days of the dates for payment set out in the contract. If the client intends to pay less than the amount on the notices, pay less notices must be issued giving notice of the amount that will be paid and the basis for its calculation. The client then makes payments to the contractor by the final date for payment.
The employer’s agent holds regular construction progress meetings and submits progress reports to the employer’s agent. The employer’s agent then prepares construction progress reports for the client.