8 UNFORESEEABLE DIFFICULTIES/PHYSICAL CONDITIONS
We looked at this topic in Part I (Section 2.6). But it may be convenient to
summarise the basic differences between the two design-build forms here.
In the Silver Book, as we saw, the Contractor bears the risk of unforeseen
difficulties unless this is otherwise stated in the contract (clause 4.12). He is
otherwise deemed to have obtained all necessary information about risks,
contingencies and other circumstances which could influence or affect the
works. By signing the contract, he accepts total responsibility for having fore-
seen all difficulties and costs of successfully completing the works.
By contrast, the Contractor under clause 4.12 of the Yellow Book may
obtain an extension of time and additional payment (his cost but not profit) if
he encounters physical conditions which were unforeseeable in the sense that
no experienced contractor by the date for tender could reasonably be expected
to have foreseen them.