11. “IN WHAT RESPECTS…(THE CONTRACTOR’S PROPOSED METHODS) FAIL TO MEET THE REQUIREMENTS OF THE DRAWINGS OR SPECIFICATION OR WILL BE DETRIMENTAL TO THE PERMANENT WORKS”. These two are the only grounds on which the engineer may refuse consent to the contractor’s methods of construction or use of constructional plant under this clause. They are discussed above in N. 7 and 8 and in N. 21.

12. “THE CONTRACTOR SHALL TAKE SUCH STEPS OR MAKE SUCH CHANGES… TO MEET THE ENGINEER’S REQUIREMENTS”. Under para. (b) the engineer tells the contractor in what respects the contractor’s proposed methods fail to meet the relevant requirements (N. 11), but the contractor chooses the steps to be taken and the changes to be made to satisfy the requirements and by implication reapplies for consent. If the engineer lays down positive requirements in instructions, it is possible that the contractor may have a claim under cl. 13 (p. 73, N. 6) apart from his rights under sub-cl. (6).

13. “THE CONTRACTOR SHALL NOT CHANGE THE METHODS WHICH HAVE… THE ENGINEER’S CONSENT WITHOUT THE FURTHER CONSENT IN WRITING OF THE ENGINEER WHICH SHALL NOT BE UNREASONABLY WITHHELD”. The engineer may reasonably refuse consent only if as a result of the change the temporary works would fail to meet the requirements of the drawings, etc., as set out in para. (b) of this sub-clause. Refusal of consent to change approved methods appears to imply “requirements” of the engineer, giving the contractor a right to compensation under sub-cl. (6).

14. THE ENGINEER SHALL PROVIDE “DESIGN CRITERIA…AS MAY BE NECESSARY TO ENABLE THE CONTRACTOR TO COMPLY”. A prudent engineer will supply these criteria with the tender documents, to minimise claims under sub-cl. (6).

If the engineer negligently misstates the actual design criteria the contractor nevertheless appears to be liable for damage to the works resulting from design of temporary works based on the criteria stated, since the excepted risk in cl. 20 (3) of a design fault is not worded so as to apply in that case (p. 97). The contractor (or his insurers by subrogation—p. 98, footnote (q)) may then have a remedy against the engineer outside of the contract to recover the cost of making good the damage, and the contractor may similarly have a remedy where the engineer’s negligence causes him to construct unnecessarily expensive temporary works. This important topic of liability for negligence outside the terms of the construction contract is discussed on p. 393.

15. “ENGINEER’S CONSENT TO THE PROPOSED METHODS…UNREASONABLY DELAYED”. See p. 365 on what constitutes unreasonable delay.

This provision covers delay with the original consent, delay in giving consent following the contractor taking steps or making changes to meet the engineer’s requirements, and apparently also delay in giving consent to a change in methods which have already been approved, within sub-cl. (4).

16. EXTRA PAYMENT WHERE “THE REQUIREMENTS OF THE ENGINEER…OR ANY LIMITATIONS…COULD NOT REASONABLY HAVE BEEN FORESEEN BY AN EXPERIENCED CONTRACTOR”. The requirements of the engineer as enshrined in the drawings and specification are of course known to the contractor at the date of tender (unless there is a variation under cl. 51—see N. 4, p. 170).

This right to extra payment therefore will take effect only in relation to an unreasonable application of standards left to the discretion of the engineer by the specification (e.g. “as the Engineer shall require”) or engineer’s requirements designed to avoid detriment to the permanent works after completion. It would hardly be a valid argument in law that the contractor did not foresee that the engineer would fully enforce detailed requirements of a specification, despite the normal practice not to “apply the book” rigidly (discussed on p.445). i′

The effect of this clause is to give the contractor some (N. 21) protection against unreasonableness on the part of the engineer in relation to temporary works. The engineer may be wise in order to minimise claims under this clause to include in the specification detailed requirements for methods of construction, materials and workmanship of all temporary works, including a required factor of safety. To do so is not unfair to the contractor, who will know at the time of tender what the engineer’s requirements for temporary works are and will have an opportunity to price accordingly. 

The hallowed phrase “could not reasonably have been foreseen” is discussed in N. 4,p. 65.

17. “AT THE TIME OF TENDER”. See p. 57, N. 2.