Home Features Commercial & Legal LEGAL: Risks in design responsibility for temporary works

Barrister Professor Rudi Klein highlights important considerations for temporary works contractors in relation to design responsibility and liability.

Design is about making a judgement or choice in relation to a wide range  of matters from aesthetic appeal to the size or amounts of required  components or materials. In the case of temporary works, design considerations will often be focused on:

  • eliminating or reducing health and safety risks (in accordance with theConstruction (Design and Management) Regulations 2015).
  • eliminating or reducing the risk of any adverse impact on the permanent works.
  • minimising the need for temporary works.
  • ensuring compliance with all relevant standards.

Design of temporary works

Temporary works such as scaffolding are enabling works that facilitate the  construction of permanent works. Very often the design of temporary works  can be just as important as the design of the permanent works. But design  teams can be reluctant to design all or part of any proposed temporary  structures. Some engineers will, in fact, exclude design of temporary works  from their appointments. This could leave the contractor, therefore, with a responsibility for designing the whole or part of the temporary works.

Scenario 1: Design team designs the full extent of the temporary structure

Let’s assume that the design team draws up a detailed specification for a  temporary structure against which the contractor has submitted their bid.  In this scenario, is the contractor free of all risk relating to the adequacy  of the design of the structure? The answer is – generally – “yes”. I say, “generally” because there could be exceptions.

What happens if the contractor later discovers that the design is not sufficiently adequate to support the construction of the permanent works? This becomes a major risk to the contractor because it is assumed  that they have bid on the basis that they can deliver the structure in accordance with the specification. If it then transpires that they will have  to incur extra costs in order to make the design workable, they may not be  able to recover these costs. They could, of course, ask for a written  instruction to carry out a variation but the other side could ‘dig its heels  in’ and argue that the cost is down to the contractor. After all, the contractor had priced on the basis of the specification and if they now had to incur extra cost in making the design work, it was down to them.

The best way to address this risk is to make clear that you have priced  on the basis of the specification and that you will claim any extra costs incurred as a result of implementing the specification.

Case law has made it very clear that a contractor has a duty to warn the other party where they discover shortcomings in the design, especially  where those shortcomings have implications for health and safety. If health and safety risks are involved, the contractor must be persistent about their warnings. If they continue to be ignored, they may even have to remove themselves from the job rather than persisting with a design solution that imports serious health and safety risk – whether to their own employees, to employees of other project participants, or to the public at large.

Scenario 2: Design team partially designs the temporary structure

If you are left to complete the design of a temporary structure, this is a high-risk scenario. You will, in effect, be taking responsibility for the whole of the design. This was the outcome of a case decided almost 15 years ago. You should, therefore, check carefully the design handed down to you before completing it.

The best way to deal with this risk is to insist that you will only take responsibility for design insofar as you have provided it.

Scenario 3: You are to have sole responsibility for the design of the temporary structure

This scenario imports the greatest risk. Inevitably, the design will have to be reasonably fit for purpose. Are you in a position to guarantee this?  Possibly not, especially if you’ve not received sufficient information about the permanent works to enable you to produce a design that is adequate in all respects, including compliance with industry standards and with health and safety regulations.

Moreover, you are unlikely to obtain professional indemnity insurance cover for fitness for purpose obligations unless those are reduced to the exercise of reasonable skill and care in carrying out the design.


Temporary works contractors must always be mindful of risks  associated with design responsibility since the implications of taking on such responsibility are potentially huge. Always seek advice if you are unsure whether you have such responsibility and liaise closely with your insurers to ensure that you are adequately covered.

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