Keep four different figures
The accepted contract describes the promised work and price basis. An invoice requests payment under that agreement; a transfer records money actually sent. The forecast also includes expected owner purchases, other services and remaining risk. None of these figures alone is the whole renovation cost.
Give every document a date, revision, supplier, project reference and tax basis. Retain the accepted quote, instruction, measured work, invoice and transfer reference. A deposit is part of the payment history, not an additional item on top of the order. A credit reduces the relevant price only when its treatment is established; a hoped-for concession is still a disputed amount.
Define a change before it becomes a vague extra
- Describe what changes and why, with drawing revision or location.
- Separate additional work from omitted original work and corrections of defective work.
- Record quantities, net/gross price, applicable tax and time effects.
- Show which old allowance or product choice is being replaced.
- Obtain the appropriate approval and keep the revised scope.
Construction-contract change rules may apply according to the actual contract. Written agreement is a useful control, but not a basis to promise that every oral instruction is legally free. BGB section 649 separately addresses expected substantial overruns of the relevant estimate. Ask for timely explanation rather than treating an arbitrary percentage as automatic authority to spend.
Reconcile cumulative requests with actual transfers
BGB section 632a links statutory progress payments to the value of performed contract work and understandable evidence. It also has conditions for supplied or manufactured materials and security. An invoice labelled Abschlag does not prove earned progress merely because another week has elapsed. Have the relevant performance and payment entitlement checked, including non-conforming work.
| Stage | Cumulative accepted amount | Previously paid | New payment |
|---|---|---|---|
| Verified first stage | 10 000 | 0 | 10 000 |
| Verified second stage | 22 000 | 10 000 | 12 000 |
| Verified third stage | 37 000 | 22 000 | 15 000 |
| Reconciled final account in this model | 50 694 | 37 000 | 13 694 |
The first three transfers total EUR 37,000. The final EUR 50,694 cumulative account is not another EUR 50,694 transfer: EUR 13,694 remains in this fictional undisputed calculation. If the previous payment record is wrong, correct the evidence before paying. Agreed advances also belong in the previously-paid column and must not disappear from the final reconciliation.
Update the work forecast and the whole project
| Item | Amount |
|---|---|
| Original work contract | 47 600 |
| Agreed additional scope | 3 570 |
| Agreed omission credit | −1 190 |
| Allowance replacement: difference only | 714 |
| Revised work account | 50 694 |
| Work payments already made | 37 000 |
| Work balance | 13 694 |
| Owner purchases | 11 900 |
| Professional services | 3 570 |
| Separate external logistics | 1 428 |
| Other identified unresolved task | 2 380 |
| Chosen remaining reserve | 4 760 |
| Full project forecast | 74 732 |
| All recorded project payments | 42 490 |
| Funds still needed including reserve | 32 242 |
All project payments are EUR 37,000 to the contractor, EUR 4,000 for owner purchases, EUR 1,190 for professionals and EUR 300 for logistics. Those total EUR 42,490 and are subtracted once. The forecast includes amounts still unpaid and a reserve; it is not a report saying EUR 74,732 has already been spent.
Handle tax, uncertainty and defects on their own terms
Check tax treatment on the real contract and each change. The example’s EUR 600 net difference becomes EUR 714 gross, not EUR 600 added to a gross forecast. Keep an agreed credit on the corresponding tax basis. Supplier situations can differ; a standard-rate calculation is not a reason to alter someone’s legitimate invoice yourself.
If the separate EUR 2,380 unresolved task is accepted at EUR 1,785, replace it: forecast EUR 74,137 and remaining funds EUR 31,647 if no new transfers occurred. Keep the reserve unchanged unless you expressly decide otherwise. A retained payment for defects remains an open liability/retention; it is not automatically a discount or free reserve. BGB section 641 gives qualified rules for due payment and appropriate withholding, requiring assessment of the actual situation.
Review the records at each milestone
- Match work evidence and current instruction to the invoice.
- Subtract all previous payments on the same account.
- Replace superseded allowances rather than adding both versions.
- Check credits, tax, scope and due dates.
- Update the full project and available cash.
- Carry disputed amounts and defects visibly until resolved.
Reno Pro can organise work stages, notes, documents and recorded payments. Keep legal entitlement and technical assessment with the appropriate professionals. The useful result is a forecast you can reconcile to accepted scope and bank transfers, with a clear distinction between paid money and what remains.
Sources, date and scope
- Bundesministerium der Justiz / Bundesamt für Justiz — BGB § 632a — Abschlagszahlungen
- Bundesministerium der Justiz / Bundesamt für Justiz — BGB — §§ 631–632, 633–637, 649, 650b–650g
- Bundesministerium der Justiz / Bundesamt für Justiz — BGB § 649 — Kostenanschlag
- Bundesministerium der Justiz / Bundesamt für Justiz — BGB § 641 — Fälligkeit der Vergütung
- Bundesministerium der Justiz / Bundesamt für Justiz — UStG § 12 — Steuersätze
Checked on 19 October 2026. Local examples concern Berlin unless stated otherwise. Check state law, heritage protection, community rules and actual work for the specific project. Teaching figures are invented euro amounts, not market prices or offers. The article projects are independent. Tax and funding calculations apply only under the stated assumptions; competent professionals resolve project-specific technical and legal questions.