Cotizar una modificación y acordar la ampliación de plazo

Raise the notice as soon as the change appears, addressed to the party the contract names, carrying the date it was raised and the date a response is due. Under NEC4 this is the compensation event notification; under JCT it is the notice that starts the extension of time running.

Por que: Both forms make the notice the thing that preserves the entitlement, and NEC4 says so out loud: a compensation event not notified within eight weeks of the contractor becoming aware of it is generally not assessed at all. A notice raised on the day costs a minute; the same notice raised in the final account costs the entitlement.

Turn the notice into a variation request and price it: measured work at bill rates where the rates apply, pro rata where the character of the work is similar, and dayworks where neither fits. Record the effect on time alongside the effect on cost, because under NEC4 the two are assessed together.

Por que: The valuation rules exist so that a change is priced the same way whoever prices it, and the disputes happen exactly where somebody skipped them. Dayworks in particular are worth what the signed sheets say and nothing more, so a daywork record agreed on the day beats a well argued rate three months later.

Build the evidence pack out of what was already recorded: the diary entries for the days in question, the correspondence, the RFIs, the approvals and the earlier notices. The pack is ordered deterministically and carries a digest, so both sides can reproduce the same bundle.

Por que: An entitlement is decided on contemporaneous records, and contemporaneous means written while it was happening by somebody who did not yet know it would matter. A pack drawn from the diary and the correspondence is that. A narrative written afterwards from memory reads as advocacy even when every word of it is true.

Take the accepted programme and show what the event did to it: which activities moved, how much float was available to absorb it, and whether the completion date actually moved. That is the extension of time argument under JCT and the assessment of the compensation event under NEC4.

Por que: Delay is a property of the critical path, and a job can lose three weeks on an activity that was never critical and still finish on time. Showing the effect on the programme separates an extension of time you are given from one you argue about, and it also tells you honestly when there is nothing here worth chasing.

Convert the agreed request into a variation order carrying the final cost effect and the final effect on time, and record the extension of time decision with its cause: employer caused, neutral, contractor caused or concurrent.

Por que: An open variation is a number two parties each remember differently. Closing it fixes both halves at once, and recording the cause of the delay is what stops the same fact being re-argued at the final account under a different name and a fresh set of adjectives.

Post the variation order against the contract so the adjusted contract sum moves with it, and let the next interim valuation pick it up. The final account is then the running total rather than an exercise in reconciliation.

Por que: A variation agreed but never posted is the commonest reason a final account comes as a surprise. Carrying each one into the contract sum as it is agreed keeps both parties working to the same number the whole way through, and turns the final account into a signature rather than a negotiation.