On the question of instructions, it all comes down to your contract
When is an instruction not an instruction? The short answer is that it depends on what the contract says. Most standard form contracts give the power to vary works to the architect.What if an employer steps in and tells the contractor to vary the works without the architect ratifying the instruction? Under those circumstances the contractor is at risk of not being paid for doing what the employer asks.Tan Eng Hoe v Liang Hooi Kiang concerns the construction of the Tet Shen Tong Vegetarian Temple, in what was then Malaya.
The architect was empowered to issue instructions, but there were many other people interested in the temple's construction. One of them asked the contractor to do various works, and the contractor obliged.
The appeal court decided that, in the absence of written authority from the architect, the contractor could not recover for the variations.
Contracts usually provide a structure for instructions to be given, valued and paid for. It is this mechanism that architects generally administer. In the absence of the instruction that the contract mechanism required, the contractor in Tan Eng Hoe could have tried recovering 'outside' the contract mechanism.
For example, it may have been possible to argue that the changed work was asked for under a separate contract, or that in asking the contractor to do the work, the employer waived the provision that instructions were to be given by the architect. While those arguments might have been successful, they would have had to be dealt with by a court or arbitrator. A certifying architect, whose powers are limited to those given under the contract, cannot deal with claims made 'outside' the contract.
The Tan Eng Hoe contract, like many standard forms, called for instructions to be issued in writing. That creates certainty as to what has been instructed, who is paying, and how much. It is a popular assumption that without a written instruction there is no instruction. Job runners will be all too familiar with the constant stream of pieces of paper called things like 'Request for written instruction' or 'Confirmation of verbal instruction' that this gives rise to. But a provision in the contract for instructions to be in writing may not be a condition precedent to an instruction being valid. It depends on the precise contract terms. In MOD v Scott Wilson Kirkpatrick, the Court of Appeal looked at the standard form GC Works 1. This has a term empowering the supervising officer to issue instructions, and a term that says all instructions should be given or confirmed in writing. The court decided that the absence of a written record as required by the second term did not preclude a valid instruction having been given under the first term.
But the MOD case makes it clear that there must actually be an instruction given. The facts of the case were that the roofing subcontractor used shorter nails than those specified, with the result that, some years later, the roof blew off. The subcontractor argued that there had been an instruction that varied the length of the nails. It was found that the supervising officer knew that shorter nails were going to be used, and went along with it.
That did not amount to an instruction.
However, there may be circumstances in which agreeing how a contractor proposes to do something may be held to be a variation. In Simplex Concrete Piles v St Pancras, an architect agreed to the contractor's suggestion to get quotes for a different way of carrying out the works, and then agreed to the contractor's changed method. It was held that the architect had given an instruction. A key difference between the two cases is that in Simplex the contractor asked for instructions, and the architect intended to order a variation. In MOD, the subcontractor did not ask for, and did not think it needed, instructions.
So read contract terms carefully. 'Within' the contract, instructions will be valid if they comply with the contract mechanism. Once claims are made 'outside' the contract, it is unlikely that the contract administrator has power to deal with them anyway. And if dealing with proposed changes to the works, be quite clear about whether instructions are being given, or not.