Construction - Managing a Domestic Subcontract Scope Change

Review the subcontract documents to confirm the claimed work is genuinely outside the agreed scope before issuing any instruction or agreeing additional payment.

Raise a written scope change instruction referencing the original subcontract, describing the additional work, location, and relevant drawings or specification clauses.

Establish whether a corresponding upstream variation instruction can be raised with the client to recover the downstream cost, and submit it before or alongside the downstream instruction.

Price the additional scope using existing contract rates wherever applicable. Agree a lump sum or daywork rate before the work begins where no applicable rates exist.

Record the instruction date, description, subcontractor, instructed scope, agreed value, and upstream instruction status in the project variation register.

Add the agreed scope change value to the subcontractor's next payment application, matched to the corresponding upstream recovery where applicable.

Site managers agree additional scope with subcontractors verbally, without a written instruction, leaving the commercial team unable to challenge scope or pricing when the claim arrives at final account.

Downstream scope changes are instructed and paid before checking whether a corresponding upstream instruction has been raised with the client, absorbing cost directly into the project margin.

Variation claims from subcontractors arrive weeks after the work is complete with vague descriptions and no reference to a formal instruction, making fair assessment nearly impossible without contemporaneous records.