Jct: Joint responsibility for design defect? JCB D&B 2016

How and by what mechanism does the Employer calculate a payment certificate when there is joint liability for a design defect?

For instance when the Contractor Acknowledges partial responsibility for design flaws, but also points to the fact that elements of the design were included in the Employers requirements, and therefore the employer is partially responsible?


Assuming this is an unamended JCT liability for failure or discrepancies in the Employer’s Requirements does not rest with the contractor (this is usually deleted however and all responsibility placed on the Contractor).

There is no simple answer to this I am afraid. You need to start with the defect, identify what it is, then who it arose and what actions could or should have been taken to deal with it. The difficulty for the Contractor will always be that he should have spotted the problem and notified of it before continuing with his design, that is, the defect should never have materialised. A reasonable starting point may therefore be that it is never going to be more than 50% the fault of the employer (the worse the fault the more obviously the contractor should have picked it up). Beyond that very broad starting point it really did become entirely reliant on the facts.

Thanks Rob, and the quick reply and I appreciate the grey.

However, supposing the employer decided that that contractor was 50% liable - how would he make that adjustment in the contractor’s certificate? and by what mechanism.

Thanks, Simon.

Simon, generally English law doesn’t follow an apportionment route so in a court you are unlikely to get this sort of situation as someone will be responsible.

That said, most problems on construction project go nowhere near a court so you need a practical and pragmatic solution. If the parties are 50:50 responsible then a reasonable approach is probably to start with sharing the consequence 50:50. I stress however that is unlikely to be how a court would decide the matter.

So the Employer would certify the works and then deduct 50% of the total cost of the defect. I couldn’t see how this would be done by clause in the contract?

As I said the law, and therefore the contract, does not really deal with a pragmatic solution but will try to impose an absolute. However, a way to approach it might be to pay for the corrected works at the contract value and issue a variation correcting the Employer part of the defect valued at half the cost of the remedial work.