Baubeschreibung and Sonderwünsche: what is actually included in a new apartment?

When you buy a new apartment from a developer (Bauträger) in Germany, you are entitled to what the notarised building description (Baubeschreibung) and plans describe. A rendering, a show flat or a sales promise is not part of that. Anything the description leaves out is either an upgrade the developer prices (Sonderwunsch, plural Sonderwünsche) or a cost you carry after handover. Before signing, read the description as an inventory, check how floor area is measured, and get every extra priced, dated and written into a document that binds the developer.

In our comparison of new and existing apartments, Apartment B needed a €5,000 fitted kitchen its building description did not include. This guide shows how to find such gaps first.

In a consumer construction contract, the developer must give you the building description in text form in good time before you commit (§ 650j BGB; Art. 249 § 1 EGBGB). The statutory minimum (Art. 249 § 2 EGBGB) covers the building and scope of work, plans with room and area figures, energy and sound standards, the essential trades, finishes, building services, quality features, sanitary, electrical and outdoor works, and a binding completion date or construction period.

These rules reach developer contracts too (§ 650u BGB; Basty, MittBayNot 5/2017) where the buyer is a consumer, as a private individual buying one flat to let usually is (§ 13 BGB); confirm this with the notary or your lawyer. Three points follow:

• The description binds because it is notarised. The rule that a pre-contract description automatically becomes contract content (§ 650k(1) BGB) is excluded for developer contracts (§ 650u(2)). The whole contract must be notarised instead (§ 311b(1) BGB), and the description is often a separate notarial deed the contract refers to (Bezugsurkunde) (Bundesnotarkammer glossary). The notary should ensure you have it at least two weeks before the appointment (Bundesnotarkammer); see what happens at the notary.
• Gaps are read against the developer. An incomplete or unclear description is interpreted in the light of all the circumstances, especially the quality standard of the rest of the description, and remaining doubts go against the developer (§ 650k(2) BGB).
• The completion date must be binding (§ 650k(3) BGB).

Brochures, films, models and show flats can help interpret an unclear description (Bundesnotarkammer). That is an argument you may have to win after completion, not an inclusion. Verbal promises fare worse: side agreements outside the notarial deed are invalid and can invalidate the whole contract (Bundesnotarkammer glossary). If something matters, it belongs in the description or the plans.

Watch for wording that moves risk to you:

• "Or equivalent" (oder gleichwertig) lets the developer substitute products. Ask what counts as equivalent.
• Furniture drawn on plans is usually illustrative. A kitchen on a plan is not in the price unless the text says so.
• Change reservations (Änderungsvorbehalt) let the developer alter the design for technical or regulatory reasons. Check they cannot reduce quality or area.

Price per square metre, rent forecasts and the tax office's cost test all depend on how area is measured.

• WoFlV (Wohnflächenverordnung, the residential floor-area ordinance) is mandatory for subsidised housing (§ 1 WoFlV) and commonly agreed elsewhere. It excludes cellars, storage rooms outside the flat and garages (§ 2(3)), counts floor under ceilings of one to two metres at half, and counts balconies and terraces at a quarter as a rule, at most half (§ 4). If the flat is built differently from the drawings, the area must be recalculated (§ 3(4)).
• DIN 277 is a standard for floor areas and volumes used in planning and cost calculation (DIN Media), not a residential-area method. Without the WoFlV weightings, its figure is usually larger.
• Tax has its own definition. For the § 7b EStG cost ceiling, the Federal Finance Ministry applies WoFlV by analogy plus ancillary rooms such as cellars, or accepts the DIN 277 gross floor area (BMF letter of 21 May 2025, nos. 50 and 51).

The contract should state the method, the balcony factor and what happens if the built area falls short, such as a tolerance and a price adjustment beyond it.

Illustrative example. Fictional figures. Suppose Apartment B's 50 m² consists of 46 m² of rooms plus an 8 m² balcony counted at half.

Both figures can be called "WoFlV". The 2 m² difference is 4 per cent of the stated area, or €10,000 of the price.

Use this alongside the developer checks. Evidence means a document forming part of the notarised contract, not a brochure or an e-mail.

A developer contract gives you no statutory right to order changes: the change-order rules of ordinary construction contracts (§§ 650b to 650e BGB) are excluded (§ 650u(2) BGB). The developer can refuse, set stage deadlines and name the price. Before agreeing any upgrade, get a written offer stating the price and the credit for the standard item it replaces, the decision deadline, any change to the completion date, and who does the work and gives the warranty.

Through the developer or direct. The developer route keeps one counterparty. A tradesperson you hire directly works under a separate contract with its own acceptance and warranty, which can complicate claims (Bauherren-Schutzbund).

Payments. Upgrades agreed with the developer increase the contract sum. The developer may take payments only as instalments under the Makler- und Bauträgerverordnung (MaBV) (§ 650v BGB; § 3(2) MaBV), so the plan should be adjusted to the new price (Krau, March 2026); see Bauträger payment plans. If changes raise the price by more than 10 per cent, you are entitled to a further security of 5 per cent of the increase (§ 650m(2) BGB).

Form. Upgrades fixed before signing belong in the notarised contract. Until the transfer agreement (Auflassung) is binding, later amendments generally need notarising unless they only remove an unforeseen difficulty without materially changing the obligations; afterwards, they can be agreed informally (BGH, V ZR 213/17). Ask the notary before you sign a change order.

Transfer tax. Upgrades agreed later with the developer attract real-estate transfer tax if legally connected with the purchase, under a separate notice (BFH, II R 15/22; § 9(2) no. 1 GrEStG). Saxony's rate is 5.5 per cent (SächsGrEStSatzG).

Illustrative example. Fictional figures, not quotes. Apartment B: Leipzig, 50 m², bought off-plan for €250,000 plus 7.5 per cent purchase costs (€18,750); contract notarised 6 March 2025; completion and transfer of benefits and burdens 1 November 2026; expected rent €825 a month from completion. The description provides vinyl flooring, standard electrical points and kitchen connections only. On 15 September 2025, before the rough electrical installation, the buyer agrees the upgrades below with the developer in a supplement whose form the notary confirmed (any notary fee excluded); the completion date is unchanged. Upgrades are paid from savings through the adjusted MaBV plan; the loan stays at €225,000. The kitchen comes from a kitchen studio after handover and is treated as outside transfer tax. Land share 15 per cent; upgrades and their transfer tax allocated wholly to the building; § 7b conditions assumed met, as in our Sonder-AfA guide. Linear AfA at 3 per cent (§ 7(4) EStG); marginal income-tax rate 42 per cent.

In one line: the upgrades add €4,241.10 to acquisition cost and nothing to the rent, and raise building AfA by €127 a year, which cuts income tax by about €53 at 42 per cent in the annual assessment (a deduction, not cash), while the kitchen depreciates separately (how to build the AfA schedule).

Built-in upgrades become part of acquisition cost (§ 255(1) HGB); a fitted kitchen is a single asset depreciated over ten years (BFH, IX R 14/15). Parquet may help letting, but a rent premium is an assumption until a tenant pays it. The upgrades are 1.6 per cent of the price, below the 10 per cent security trigger. B's headroom under the § 7b ceiling falls from €31,562.50 to €27,321.40; its special-depreciation base stays at the €200,000 cap (Sonder-AfA).

Time is the other cost. Had the parquet delayed completion by a month, about €825 of expected rent would have been lost. Completion in December with handover in January would also have cost B its special and declining-balance depreciation, which require acquisition by the end of the completion year (§ 7b(1) EStG; § 7(5a) EStG). At acceptance, check each upgrade against the signed supplement (new-build acceptance).

For purchases in Berlin, Dresden or Leipzig, Alpha Minoris's Buyer's Agent service can collect the building description, Bezugsurkunde, plans, area calculation and upgrade price list, and coordinate your questions to the developer before signing, so the answers arrive in writing while the draft can still change. You do not need to live in the city. Legal review stays with the notary and your lawyer, technical review with an independent expert, and tax treatment with your tax adviser (Steuerberater).

Before signing for a new apartment, put the building description, plans and every agreed upgrade side by side with the draft contract. Discuss your first rental property with Alpha Minoris.