Design and Build and Traditional procurement are two different routes with their own merits.The criteria to consider come from the client’s requirement on time, cost, quality, and risk for the project.
In terms of time, design and build has an early start on site compared to Traditional procurement, which has a late start. In traditional procurement, construction will begin when the contractor is appointed, and this is only achieved once the tender is completed and prior to which the design is completed in its entirety.
The certainty of the time of completion would only be achieved after one of the tenders have been accepted. This could be a few months or years in the project; therefore the certainty will only be achieved late. The traditional route is sequential, and the design, tender and construction cannot be run parallel.
However, in design and build the client appoints a design team to prepare a small amount of design (‘the employer’s requirement’),and goes out to tender early to appoint a contractor to undertake both the design and construction of the project.
This allows the contractor to undertake the detail design while the construction works are taking place. Hence, an early start as the design is ran parallel with the construction. Due to the early tender, the certainty on the duration of the project is achieved early.
If the client is looking for a competitive price, traditional procurement provides the client with fair and competitive prices without the contractor including high risks compared to design and build. In design and build, the contractor is undertaking both the design of the unfinished elements and construction activities.
As the design is not complete, they would likely get prices that are not like for like which would also include for much risk pricing on the un-complete design. However, the client will know of the prices earlier in the project as the tender is undertaken earlier.In Traditional procurement, as the design is completed fully, the client would gain a more competitive price as all the tenderers would be pricing on the same design and specification.
Therefore achieving a fair and competitive price. With the design complete it would be less likely to have any design risk for the contractor to price. However, if there is a contractor’s design portion there would be an element for which the contractor would be required to price for their risk. As the tender is only undertaken once the design is complete, the certainty on the cost can only be known at a later stage of the project.
In terms of quality input, the client does not have much input in the design and build route compared to the traditional route. In the design and build route the client would engage the contractor for both the completion of the design and construction works. So if the client wants to specify a particular type of skirting he may only do so in his employer’s requirement earlier in the project and not once the contract is let. Moreover, the certainty of the quality is only known when the tender is accepted.
However, in traditional procurement the client would have much input in the design before it is completed to go out to tender. Any requirements that the client wishes to have can be implemented while the design is being undertaken. However, the certainty of the quality will only be known after the design is fully completed.As both routes do not engage the contractor at the early stages of the project; the client would not benefit from build ability insights from the contractor.
This would include insights on the operation, logistics and location restrictions of certain types of projects. An example would be build ability in the city centre where logistics would restrict the design as it may be operationally difficult to setup scaffold for a particular cladding. However, if the contractor is engaged on a two-stage tender, there may be the opportunity of gaining the build ability insights required.
Finally, we have to way the risk of the client’s need for the project at the moment in time and with the criteria discussed above.