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Buildability in construction contracts

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Posted by Philip Harris on 12 March 2015

Philip Harris Partner & Solicitor-Advocate

It is important to realise that when a contractor quotes for a job, he is accepting the technological challenge that goes with it.

The contractor is saying that he can do that particular job and that he can deliver the end product on that particular site in that particular location.

It follows from this that the defence of “non-buildability” is not a runner.  The contractor cannot simply say, “I tried but it was impossible”.

A contractor could, of course, include a special term in the contract saying that he does not promise that the job can be done and that he relies on somebody else, such as a professional designer.

However subject to this, he promises that he can do the job.

Buildability is not to be confused with the separate issue of “frustration” or impossibility of performance, where subsequent events conspire to make the original scheme impossible (such as an indefinite stop on work due to a war or a local authority or government order).

The duty to warn

This responsibility for buildability goes hand in hand with another duty of the contractor – the duty to warn.

The contractor is responsible for the “how” of the construction process.  This applies equally to finishing trades such as decorators.  If there is a problem with the feasibility of the works, then the contractor should warn of this.

In one famous case, a contractor was asked to knock out a number of walls.  He was given a drawing which showed load bearing and non-load bearing walls.  He knocked out the walls which were shown as non-load bearing and the building became structurally unsafe.  The judge concluded that any competent builder should have known that the drawing was incorrect and warned that what was being asked to do was unsafe. 

The contractor is responsible for the temporary works such as scaffolding and all enabling works which lead to the permanent finished result.  These works are his “province”.  Whereas the “province” of architects and engineers and other professional designers is normally the design of the permanent works.

So generally speaking, the contractor does not have a defence that the architect or other designer did not warn or tell him how to go about his works. 

The contractor also does not have a defence that the architect or any of the client’s agents did not detect a defect at an early stage and save him money by requiring him to put it right early on. 

The good news is that the contractor generally does have a defence that he complied with the specification provided or that he did what he was told to do.

There is a general rule that if plans and specifications are provided to a contractor to work to and especially if the building owner employs an architect, then the contractor will not have to do more than carry out the work according to the plans and specifications in a workmanlike manner and using proper materials.  The owner will be unable to complain if the unsuitability of the final result is due solely to exact compliance with that design, subject to the duty to warn.

However virtually no contract completely defines the work to be done.  In the majority of cases there is an element of choice to be exercised by the builder over the use of materials and the nature of the work.  For example, the contractor may be responsible for the mix of plaster or paint.  If he is not told exactly what to do and he makes decisions for himself, then he takes on a design responsibility.  It is often said that, “design is choice”. 

Therefore the argument, “I did exactly what you asked me to do” is not always the cast iron defence that it appears to be.

Contractors must be careful not to inter-meddle in the design process where they have not agreed to take on design under the contract.  This is a trap that the very good contractor often falls into.  In order to help, and relying on his experience, he suggests that something could be done in a different and better way.  If he doesn’t want to accept design responsibility, then he must get the client or his architect to give a clear instruction accepting responsibility for the revised method.  Otherwise, by interfering in the design, the contractor will have taken on design responsibility.

So there are a number of specific lessons here:

  1. Contractors will accept responsibility for buildability unless they exclude it.
  2. Contractors are responsible for the temporary or enabling works such as scaffolding.
  3. Contractors may be able to rely upon the defence that they followed the specification precisely.
  4. This is subject to their having a duty to warn that what they are being asked to do is not practical.
  5. “Design is choice”; so if you choose what to do where the contract is silent, or if you suggest better ways of doing things, try to get a clear instruction accepting your choice and agreeing to accept responsibility for it.

About the author

Philip Harris

Partner & Solicitor-Advocate

Philip has 30 years’ experience as a construction solicitor and advises on all aspects of construction law.

Philip Harris

Philip has 30 years’ experience as a construction solicitor and advises on all aspects of construction law.

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