NEC Option B Design and Build

We tender which has a BQ based on preliminary design and the Employer is asking for a price based on a full design by the Contractor. The final Contractor design is therefore likely to be different than the preliminary design and the BQ will not match the WI produced by the Contractor. I don’t see a contractual mechanism under Option B for the BQ to be amended to reflect the Contractors design so the quantity risk reverts to the Contractor which is not the intent of Option B.

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Hi Steve, Option B is perhaps not the best main Option to have chosen for this project, but there may be a couple of possible solutions but I need more information.
The important document will be the Scope provided by the Client, is the preliminary design included within the Client’s Scope?
If not how does it describe what it wants the Contractor to design and where is the preliminary design included within the contract?
Did the Contractor identify Scope for it’s design within the Contract Data part two?

Hi Steve

The preliminary design is the Client’s Scope and is effectively the specification. The requirement is to take this preliminary design to full design.

We have not provided our scope for design in CD Part 2, but could if needed to (we haven’t yet submitted)

Many thanks


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Steve, so my answer can only go so far and I have had to ask another question of you at the end.

The first thing to say is that the Contractor only provides what is in the Scope, clause 20.1, nothing more nothing less.

Secondly, the BOQ must have measured the Scope (preliminary design) in accordance with the method of measurement stated in CD1, if it doesn’t and if not corrected prior to entering into contract, then once in contract it has to be corrected by the PM and that triggers a CE under clause B60.6. If it doesn’t identify and quantify all of the Scope then both B60.6 & B60.7 apply and again the PM has to correct it. In both instances the PM & Contractor should notify each other of an ambiguity or inconsistency between the BoQ and the method of measurement and/or Scope and the PM has to state how it will be resolved, i.e. PM corrects it.

Once in contract and you start to progress the design (cl21.1), you have to submit the parts of the design to the PM for acceptance as stated in the Scope (cl21.2) – you cannot proceed with the work until the design has been accepted by the PM and also be aware of the status of the PMs of acceptance – cl14.1.

The Price for Work Done to Date in Option B is based on a re-measure of the BOQ, it is the actual quantity of work done multiplied by the rate for the item in the BOQ, so provided you are merely increasing or decreasing quantities there’s no problem – be aware of both CEs under B60.4 & B60.5.

If when developing your design you introduce something additional that was not in the Client’s Scope but the Client/PM agree that they want it, then the Client’s Scope must be changed to include it as a requirement, otherwise the work will not comply with the Scope and in effect it will be a Defect under clause 11.2(6) 1st bullet. If the Client does not want what you propose, then remove it from your design and do not provide it.

The problem comes when your design develops from a performance requirement stated in the Scope, which has not been identified and quantified within the BoQ, now this is tricky and why I said before that perhaps Option B is not the best option to have chosen.

Rather than me trying to invent a scenario could you provide an idea of the sort of thing you think might fall into this category?

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Hi Steven

Thanks for that.

I agree with you that it is not the right procurement option but we have not been able to pursued theClient to either change the option or clarify the intent once a contractor is appointed.

I wondered if 60.1.18 might come into play if the Client causes the Contractor to be in breach by virtue of not being able to comply with Cl20.

Many thanks for your time.

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Steve, I don’t think 60.1(18) would be it but maybe 60.1(14) which links into clause 80.1 which under the 3rd bullet holds the Client responsible for a fault in the Client’s design in the Scope or an instruction from the PM changing the Scope.
I am struggling to think how the BoQ caters for things like ironmongery, if the preliminary design doesn’t include ironmongery what has been taken for within the BoQ?
I would suggest that you raise a tender clarification and ask the Client to resolve the issue now before the tenders are submitted, that way all tenders will be based on the same information and level of risk.
Good luck.

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Many thanks for your time on this, much appreciated.

If anything interesting happens I’ll let you know.

Best regards

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