If the contractor is to ‘complete the design’, does that mean that existing design can be assumed to be correct?
The answer to that question is that it all depends on the type of contract being used. Under the JCT WCD contract the contractor was required to complete the design of the Works. It used to be thought that the contractor was not being given responsibility for the design as a whole, but merely to complete what was, presumably, left incomplete. That seems the sensible view. However, that view changed with the judgment in Co-operative Insurance Society Ltd v Henry Boot Scotland Ltd (2002). Although this case concerned the JCT 80 form of contract as amended by the Contractor’s Designed Portion Supplement, the CDP had many similarities to the design and build contract, importantly including an obligation that the contractor must ‘complete the design for the Contractor’s Designed Portion’. Some other clauses were almost identical to the equivalent clauses in the design and build contract. The court took a very clear approach:
In my judgment the . . . process of completing the design must, it seems to me, involve examining the design at the point at which responsibility is taken over, assessing the assumptions upon which it is based and forming an opinion whether those assumptions are appropriate. Ultimately, in my view, someone who undertakes, on terms such as those of the Contract . . . an obligation to complete a design begun by someone else agrees that the result, however much of the design work was done before the process of completion commenced, will have been prepared with reasonable skill and care. The concept of ‘completion’ of a design of necessity, in my judgment, involves the need to understand the principles underlying the work done thus far and to form a view as to its sufficiency. . . . If and insofar as the walls remained incomplete at the date of the Contract, Boot assumed a contractual obligation to complete it, quite apart from any question of producing working drawings.
This judgment makes clear that the contractor’s obligation to complete the design under the CDP supplement extends to an obligation to check the design which has already been prepared to make sure that it works. The contractor cannot simply assume that information including design already provided is correct. Because of the similar wording, it appears that the judgment applies to WCD 98 also. Indeed, it is probably not going too far to say that wherever a contract calls upon the contractor to complete the design, its obligation extends to checking the original design before proceeding.
When drafting the new design and build form, DB, the JCT have taken account of this judgment. A new clause 2.11 has been included which provides that the contractor is not responsible for the Employer’s Requirements nor for verifying the adequacy of any design contained in them. It seems to follow that if the employer has caused the whole of the design to be prepared by an independent architect and included within the Employer’s Requirements, there will be no design to complete and the contractor will have no obligation in this regard. At the other end of the scale, if there is no design included in the Employer’s Requirements, the contractor will be responsible for all the design. If, under DB, the contractor is handed a partly finished design, it appears that the contractor’s obligation will simply be to complete the design without carrying out any checks, unless of course, there are obvious problems with the original design. This effectively reinstates the position as most people thought was the case until the Co-operative Insurance case.