How do you control renovation extras, advances and the money still needed?

Freeze the starting agreement

Save the accepted quotation, drawing revision, specifications, exclusions and price validity together. Identify which prices are fixed, which quantities are remeasurable and which amounts are provisional. The first budget should show the operation’s IVA basis and final payable total, not leave tax to the last invoice.

Consumer law articles 60 and 60 bis address pre-contract information and express consent to additional payments. Turn that into a practical agreed change process with the contractor: who may approve, how scope and price are stated and how programme effects are recorded. A spoken request to “do it better” is a poor cost record even when both sides are acting in good faith.

Classify what has changed

• Additional work: a genuinely new item outside the accepted scope.
• Omitted work: an agreed removal with a priced credit.
• Allowance replacement: remove the included amount and insert the selected actual amount.
• Quantity adjustment: use the agreed measurement method and rate.
• Unresolved finding: a decision requiring investigation or a new proposal.

Ask the contractor to identify the original item and reason for each change. If a correction is already part of its responsibility, do not automatically relabel it an owner-requested extra. Where responsibility or price is disputed, record the facts and seek appropriate advice rather than treating your spreadsheet as a legal determination.

Approve a complete change, not just a number

Changing a service route or wall can also change the municipal procedure or community question. Confirm those implications before proceeding. For an urgent condition needing immediate professional action to make safe, record what was necessary, who was contacted and the cost basis; then agree the permanent repair scope. Urgency should not erase the record.

A contract ledger with credits

The forecast is €50,215 + €3,000 + €1,300 + €2,000 + €4,000. It assumes only the €36,300 contractor payments have been paid so far. The €2,000 unresolved repair is neither an accepted variation nor part of the €4,000 unallocated reserve. If the two described the same risk, keeping both would overstate funding.

Payments reduce what is unpaid, not what the work costs

Suppose the paid €36,300 consists of an initial €9,680, a stage payment of €14,520 and a later €12,100. These sum to €36,300. The initial €9,680 happens to be 20% of the original contract; that is this example’s arrangement, not a prescribed deposit. The payments leave €13,915 of the current agreed contractor price unpaid.

Do not add the payments to the €50,215 contract total. Do not reduce project cost because money left your account. For each invoice, identify whether it states a new instalment or a cumulative amount and how earlier advances are credited. Match the payment to the agreed milestone and save the invoice and payment evidence.

Reconcile tax and allowances without shortcuts

A €1,815 replacement for a €1,210 included allowance changes cost by €605 gross. Adding the entire €1,815 without removing €1,210 would overstate the agreed price. A credit should have its correct invoice and tax treatment recorded, not merely a handwritten negative number in an otherwise unrelated quote.

AEAT’s renovation rules and material-cost FAQ explain why 10% cannot be assumed for every extra or labour line. Ask the contractor to confirm the treatment of the actual operation and any changed material mix. This example keeps 21% throughout for clarity; it does not establish the tax result for every real variation. Do not add another 21% to already gross figures.

Use a weekly reconciliation

1. List accepted changes and credits since the previous update.
2. Reconcile the current agreed price to the original and those changes.
3. Match invoices and payments, including credits for earlier advances.
4. Update owner purchases and outside costs without duplicating contract items.
5. Keep unresolved work separate from accepted commitments and unallocated reserve.
6. Compare the revised total and timing with available household funding.

If the €2,000 forecast repair is later accepted for €1,700, move €1,700 into agreed costs and remove the whole €2,000 estimate. The funding forecast becomes €60,215, with €300 less forecast cost if every other line is unchanged. Adding the new agreement while retaining the old estimate would count the same repair twice.

Close documents as well as numbers

The Madrid consumer guidance supports keeping the written scope, invoice and documented amendments. At handover, reconcile the final account against delivered work, accepted changes and payments. Record defects and missing documents with dates and responsibility under the actual agreement. Do not invent an automatic retention right or universal percentage for every Spanish contract.

Reno Pro can organise stages, planned and recorded costs, notes and payments. Use the same distinction in any spreadsheet: committed is not paid, unpaid is not additional cost, and reserve is not permission to order work. A reliable forecast should tell the household both the expected total and the cash still required, with the assumptions visible.

Sources, date and scope

• BOE — Real Decreto Legislativo 1/2007: artículos 60 y 60 bis
• Agencia Tributaria — IVA: obras de renovación o reparación de viviendas
• Agencia Tributaria — Preguntas frecuentes sobre obras y reparaciones en inmuebles
• Comunidad de Madrid — Reformas del hogar: presupuesto, factura y reclamaciones
• Ayuntamiento de Madrid — OLDRUAM 6/2022: artículos 6, 7, 8 y anexos I–IV

Sources checked on 19 October 2026. Local procedures and examples concern the city of Madrid unless stated otherwise. IVA explanations concern the territory where that tax applies, rather than the separate tax systems of the Canary Islands, Ceuta or Melilla. Original worked calculations are teaching examples for the stated scope, not market averages or contractor offers.