Off-plan sales process: how do DACH developers go about selling apartments before construction?

How a Bauträger approaches selling apartments before construction

In the DACH countries, selling apartments before construction is a regulated procedure, not a marketing campaign. The Bauträger is developer, building client and seller in one, so it answers to the buyer for completing the building and must provide the statutory protection for payments.

The legal framework differs from country to country. Germany applies the Makler- und Bauträgerverordnung, with payments tied to construction progress; Austria uses the Bauträgervertragsgesetz, with a choice of security model; in Switzerland the contract is notarised under cantonal rules. A lawyer or notary should always confirm the details, but the logic is the same everywhere: the buyer sees the documents before paying anything.

For a developer in Slovenia, this is a useful pattern. An off-plan sales process works when the documents, the presentation and the procedure are ready before the first enquiry, not after it.

Documentation for an off-plan sales process: what must be ready

A Bauträger usually assembles a sales file that the buyer receives before the notary appointment or contract signing. The file must be internally consistent: every figure in the floor plan, the specification and the price list has to match the contract.

The most common source of disputes is a mismatch between the visualisation, the description of works and the contractual position. The construction specification should therefore be the leading document, with visualisations serving as illustrations that follow it.

The minimum content of a sales file:

• construction specification and fit-out standard (in German, Baubeschreibung)
• floor plans with dimensions and an area calculation based on the rule that applies in the target country
• the condominium deed, for example the Teilungserklärung in Germany, the Nutzwertgutachten in Austria or the creation of condominium ownership in Switzerland
• payment schedule by stage and the method of securing buyers’ payments
• list of optional extras and the deadline for choosing finishes
• programme with the expected handover date

Digital presentation as part of the sales file

Buyers in the DACH region expect to understand an apartment without visiting a sales office, as many enquiries come from other cities or countries. An interactive building model with floor and unit selection, together with a free-roam 3D walkthrough in the browser, shows the space, light and layout that a floor plan cannot convey.

The key is that the digital presentation draws on the same data source as the price list and unit status. If the model shows an apartment as available when it is already reserved, trust falls faster than a good image can build it. Such a link between the model and availability can also be built with solutions like those developed by ARHIX, but the principle matters more than the tool.

Add a clear label to visualisations showing what is contractually fixed and what is merely illustrative, such as furniture, planting or the view from the balcony. This protects the developer and, at the same time, makes the whole offer more credible.

Reservations: when, how and on what terms

In DACH markets, a reservation is not a substitute for a contract. It is usually a written agreement that holds a unit for a specific buyer for a limited period while the notary appointment or contract is being prepared.

Rules on reservation fees and refunds vary between countries and are in some places strictly policed, so align them with a lawyer before publication. The document must state clearly how long the reservation lasts, what happens if the buyer withdraws, whether the amount is refundable and who the contracting party is.

The procedure should be identical for every buyer: request, confirmation, deadline, contract. A single record of statuses (available, reserved, sold) prevents double reservations and lets buyers see the current status at any time.

Communication from first enquiry to move-in

An off-plan purchase runs for months or years, so communication is not a one-off event. During that time the buyer makes major decisions on financing, fit-out and modifications, and needs reliable information to do so.

German and Austrian buyers value precision and traceability. Every important piece of information should be recorded, dated and available in one place, not scattered across emails and phone calls.

Agree a clear rhythm:

• reply to every enquiry within one working day
• send material after each conversation with a summary of what was agreed
• provide regular construction progress reports at intervals known in advance
• notify the buyer of any change to timing or specification, tied to an entry in the record

Common mistakes in off-plan sales

Most problems arise from organisation, not from the offer itself. The developer publishes an attractive presentation, but the legal and technical foundation is not in place.

The list below covers the mistakes that occur most often. Review it with your lawyer, architect and sales team before going public.

• a presentation without an agreed construction specification
• area calculations that differ between the floor plan, the price list and the contract
• a reservation with no expiry date and no refund conditions
• availability managed by hand across several spreadsheets
• buyer-requested changes agreed verbally with no written record

What you can do next

Start with an audit: for each document on the list, check whether it exists, who is responsible for it and when it was last updated. Then define a single source of data for units, prices and statuses, from which the presentation, the sales team and the contracts all draw.

To get a feel for what a free-roam 3D walkthrough in the browser looks like, you can view the public demo of a sample house at https://moderna-hisa-3d.netlify.app/. For legal questions on off-plan sales, consult a local lawyer or notary in the target country.