Builder variations: how to agree extras before the bill arrives

A variation is a change to the work agreed in the contract. It may be a homeowner choice, a design change or necessary work discovered after opening up the building. The key question is what changed from the original scope, why, and what does that do to price and time? A verbal “we’ll sort it later” leaves both sides exposed.

Start with the original documents

Find the signed quotation or contract, drawings, specification, exclusions and any agreed allowances. Compare the proposed extra against them. If a builder asks for more to install a feature already specified and priced, ask why. If the drawings never identified it, or the existing structure has concealed damage, the position may be different. Do not assume that every surprise is automatically an extra or automatically included.

Provisional sums and allowances deserve special attention. An allowance may cover only a defined amount or part of the work. Check whether the new charge replaces the allowance, supplements it, or duplicates something already included. Our guide to reading a builder’s quote explains the underlying scope issue.

Get a written change before proceeding

For each proposed variation, record the location, description, reason, reference drawing or photograph, labour and materials basis where appropriate, net increase or decrease, tax treatment, effect on other work and revised completion date. Ask what happens if you decline it. Give the builder a clear written approval or rejection according to the contract’s procedure.

Some urgent discoveries must be made safe immediately. Record photographs and the condition before work is covered, and separate emergency protection from the permanent solution. A structural, electrical or other specialist judgement may be needed before selecting the remedy.

Test the consequence, not just the line price

A £1,000 change can delay a kitchen installation, cause a second scaffold visit or hold up inspections. Conversely, removing work should produce a clear credit. Update the programme and payment schedule, and show the cumulative effect of all approved changes. A stack of individually modest extras can exhaust a contingency.

Keep a change register: reference, date raised, status, cost, time effect, approval and invoice. Reconcile it at each payment. If the builder is already asking for more money than quoted, that separate guide helps you assemble the facts before responding.

When the price is disputed

Do not silently instruct work while arguing about its price. Ask for the contractual basis, the supporting records and the alternative options. Preserve correspondence and site records. If the issue concerns defective work, a design error or a formal dispute, obtain the right independent specialist or legal advice for that issue. Build Advocate can help you understand the scope, cost and practical next step without taking over your project.