Define the apartment and the finished result
Record rooms, measured areas, existing installations and retained finishes. Repainting an occupied home is different from renewing a vacant apartment’s bathroom, wiring and floors. Use a room schedule to state what stays, what changes and who specifies the result. Check substrate and installation condition before treating all visible work as straightforward.
Ask about common building elements before removing walls or changing a shared service. WEG section 5 distinguishes private from common property; location inside the apartment does not settle ownership. For the Berlin example, the district building authority is the appropriate contact for project-specific public procedure. Community consent and public permission are separate checks.
Allocate supply, installation and logistics
- State who supplies tiles, sanitaryware, lights and doors, and who installs them.
- Distinguish internal protection, debris carrying, external transport and disposal.
- Define what electrical or water work is local to the apartment and what remains excluded.
- Name professional surveys, design and checks separately.
- Ask for payable totals, tax treatment, quantities, exclusions and offer validity.
The consumer guidance on commissioning trades supports detailed, comparable offers. A cheap quotation that omits supplied products is not a cheaper complete project. Add every known exclusion to the budget, even if its price is still provisional. Do not charge cabinet fitting twice when it is already in the kitchen supplier’s contract.
Build a complete funding example
| Item | Amount |
|---|---|
| Protection and site setup | 2 000 |
| Demolition and internal carrying | 3 500 |
| Specified electrical work | 6 500 |
| Private water and drainage | 5 000 |
| Bathroom substrates, waterproofing and tile laying | 7 200 |
| Other rooms: wall and substrate repairs | 4 000 |
| Other rooms: floor installation | 4 800 |
| Painting | 4 500 |
| Door/fixture fitting and final connections | 1 500 |
| Checks and final cleaning | 1 000 |
| Net work | 40 000 |
| 19% VAT | 7 600 |
| Gross work | 47 600 |
| Item | Amount |
|---|---|
| Gross work package | 47 600 |
| Owner finish products | 11 900 |
| Fitted kitchen and appliances | 16 660 |
| Survey, design and agreed checks | 3 570 |
| External deliveries and disposal | 1 428 |
| Temporary living and storage | 2 400 |
| Identified unresolved work allowance | 2 380 |
| Chosen reserve | 7 616 |
| Total funding | 93 554 |
Owner finish supply is EUR 10,000 net: EUR 5,000 of floor/wall products, EUR 3,000 of sanitaryware and EUR 2,000 of lights/door products. The kitchen is EUR 14,000 net including its agreed fitting and appliance supply; final service connections are in the work package. Electrical and private water rows cover rough services throughout the flat; bathroom construction and other-room finishes are separated. The kitchen supplier fits cabinets; the work package fits sanitaryware/doors and makes appliance service connections. The reserve is a chosen 10% of gross work plus those two purchase packages: EUR 76,160 × 10%. It is not a legal percentage.
Compare gross amounts and equivalent scope
The standard VAT rate is 19%, but a supplier’s actual tax position must appear in its offer. Do not add tax again to an already gross amount or apply the sample rate to every funding line. Here work is EUR 595/m²; complete funding is EUR 1,169.43/m² after rounding. Neither is a German average.
Send the same plan, specification and responsibility list to bidders. Keep a dated comparison of unit quantities, total price, exclusions and completion evidence. An allowance for an unanswered task remains visible until a firm scope replaces it. A square-metre headline cannot explain whether the kitchen, professional fees or temporary housing were counted.
Control choices without counting them twice
If included door products rise by EUR 600 net, the gross increase is EUR 714 under this example’s tax assumption. Using reserve leaves EUR 6,902 and preserves total funding. Keeping the original reserve raises funding to EUR 94,268. Record the replacement of the old item, not the entire new door order as an additional cost.
Put supplier deposits, contractor progress payments and professional invoices on one calendar. A payment reduces the remaining balance; it does not increase the contract price. Keep the EUR 2,380 identified allowance distinct from the reserve and explain which unresolved question it covers. Otherwise the same risk can quietly appear in both.
Decide when the budget is ready
- Resolve the main survey, ownership and permission questions.
- Issue one measured scope and final product schedule.
- Replace assumptions with complete gross offers where available.
- Agree inspection evidence and payment milestones.
- Keep unresolved items and reserve separate.
- Update the forecast whenever scope, tax treatment or timing changes.
Reno Pro can hold the work stages, purchases and recorded payments together. The accepted offers and professional documents remain the evidence behind the figures. Release the budget when you can explain what is included, who pays each item and how much money must still be available.
Sources, date and scope
- Verbraucherzentrale — Handwerker: Auftrag, Abnahme und Rechnung
- Bundesministerium der Justiz / Bundesamt für Justiz — UStG § 12 — Steuersätze
- Bundesministerium der Justiz / Bundesamt für Justiz — WEG § 5 — Sondereigentum
- Land Berlin — Senatsverwaltung — Informationsportal der Obersten Bauaufsicht
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.