What is a variation in construction?

A variation is a change to the work the contract originally described: something added, omitted or changed. A subcontractor who is told to do extra work should record the instruction before starting, so the extra can be valued and paid.

Why variations go unpaid

Extra work is often agreed on site in conversation. Weeks later there is nothing on paper to show who asked for it, when, or what it involved. An extra with no record is hard to recover.

What to record

• Who instructed it, and when.
• What was changed, with photos.
• The time and materials used.
• The price, and the date it was sent for agreement.

Names under different contracts

JCT and informal contracts use the word variation. NEC4 contracts deal with changes as compensation events, which have their own notification rules and time limits.

Common questions

Do I need a written instruction for a variation?

It is far safer. Many contracts require one. If it was given verbally, confirm it in writing straight away, with the date.

How do I value a variation?

By the method in your contract, often your agreed rates or a fair valuation. Send the price promptly with the evidence.

This page is general information for UK construction subcontractors and is not legal advice. Contracts differ, so check yours, and take advice on a specific dispute.