Whose Design Is It Anyway?

Every building contract will outline who is responsible for the design. It is critical that you have a clear understanding of who is responsible for what aspects of design and ensure this is managed effectively. Failure to understand, manage and mitigate this could have expensive consequences for you and your business.

There are many forms of building contracts in existence, including standard forms, amended standard forms and bespoke contracts. Each of them should and most likely will make it very clear who is responsible for each design element. If it does not, do not proceed until this has been clarified within the contract documents and you have adjusted your tender accordingly.

Types of Contract and Design Responsibilities

Traditional contracts

  • Design and construction activities are split
  • Employer does not have a single point of responsibility.
  • Others design the works (Architect, Engineer, other design professionals)
  • Contractor builds in accordance with the design provided by others

Design & build contracts

  • Contractor is responsible for both design and construction
  • Provides a single point of responsibility for the Employer

Contractor designed portions (CDP’s)

  • Some contracts give you, the Contractor, design responsibility for specific “portions” of the work
  • This should be set out very clearly in the contract. Again, if it is not, do not proceed until this has been clarified within the contract documents and you have adjusted your tender accordingly.
  • Interface issues are critical with CDP’s, such as fixings, flashings, sealing etc – it is important that the contract is equally clear in this regard

Other implications for Design Responsibilities

If you have any design responsibilities under the contract at all, there are likely to be further implications for you so make sure you clearly understand what your obligations are in respect of…

  • The requirement to hold Professional Indemnity (PI) insurance (to be covered in a future article in more detail)
  • Additional responsibilities under CDM regulations (to be covered in a future article in more detail)
  • Collateral warranties (covered in a previous article)

Reasonable skill and care V Fitness for purpose

Check the contract to see what design obligation you are potentially signing up for. It is likely to be either a “reasonable skill and care” or a “fitness for purpose” burden. The following paragraphs summarise what this could mean for you.

Reasonable skill and care

  • Without written terms and conditions to the contrary, a professional designer (and you the contractor where you have a design responsibility) will have a duty to act with reasonable skill and care.
  • Common law test for negligence provides that a professional person is not negligent if he carries out his work to the same standard that another reasonably competent member of his profession would have met.
  • This is a reasonable and fair requirement and you should not agree to anything beyond it

Fitness for purpose

  • Imposes a higher duty, as it is an absolute obligation to achieve a specified result,
  • A breach does not require proof of negligence
  • In a construction context, this means that you, the contractor are effectively guaranteeing that the components and the finished building will be fit for their intended purpose
  • Avoid signing up for fitness for purpose obligation – not a good deal for you

A good way of demonstrating why you would want the reasonable skill and care burden and not fitness for purpose is that a Doctor cannot guarantee to always cure their patients (an absolute obligation), only to act with the reasonable skill and care expected of someone in their profession.

Of course, with all legal matters, there are many “grey” areas and this article cannot and is not intended to deal with this complex subject completely. It outlines the basic principles and provides some guidance for you and your business

Procurement downstream of Design Responsibilities

  • You may have in-house design capabilities, but are more likely to need to out-source these
  • Could be through design consultants and/or designing sub-contractors
  • Make sure the design responsibilities you procure are back-to-back with your own design responsibilities…. avoid any gaps/holes in the design responsibilities that would become your problem later
  • Have the right tools and processes in place to enable you to effectively procure, allocate, manage and mitigate the design responsibilities and risks
  • To be covered in greater detail in a future article


Be clear on what, if any design responsibilities you are taking on, plan for them and procure them appropriately. Often well-intended attempts to help a project move along can mean you have taken on board a design responsibility that could prove costly later.

If the Architect/Engineer/Designer has not detailed something, submit a query and do not proceed until it has been answered fully.

If you need any further advice or specific input on projects in respect of design responsibilities, we can support you and your business with this.

Design responsibilities Question mark, puzzle pieces and two people scratching their heads.

Other posts

There’s A Difference Between Us
Tender Reviews and Risk Management
“We don’t like Dayworks”
Getting Paid

Get in touch

Join our mailing list

To hear more from the team at VOLOCO, fill out the form below. By filling out the below for you are happy to receive occasional emails from the team.