An older property whose drawings date from construction (when they still exist at all) goes on the market with a handicap: the buyer can neither check the advertised floor areas, nor price their works, nor picture themselves in it. A 3D survey followed by BIM modelling fixes all three in a single site visit: floor areas calculated to the SIA 416 standard, as-built drawings that match the building as it stands, and a digital model the buyer can walk through and reuse for their own project. For a villa, expect a few thousand francs and seven to ten working days, to be weighed against a negotiation that stalls or a discount conceded for lack of data.
This article is written for property management firms, brokers and owners preparing to sell an older property in French-speaking Switzerland.
Why a property without reliable drawings sells less well
In a transaction, uncertainty is always paid for by the same side: the seller’s. In practice:
- The advertised floor areas cannot be verified. The listing says 240 m², the land register says something else, the 1972 drawings something else again. The buyer, or their bank, keeps the lowest figure and negotiates on that basis.
- The works cannot be priced. Without as-built drawings, the buyer’s contractor or architect can only produce a broad estimate, with a contingency for the unknown. That contingency, the buyer deducts from their offer.
- Due diligence drags on. Every unanswered question (ceiling heights, wall thicknesses, attic floor area) adds a back-and-forth, an extra visit, a delay. And a delay is an opportunity to pull out.
The classic sales file (photos, land register extract, archive drawings) documents what the property was. A 3D survey documents what it is.
What the 3D survey brings to the sales file
Verifiable SIA 416 floor areas
The point cloud produced by the laser scan captures the real geometry of the building to the centimetre. The model built on it makes it possible to calculate floor areas according to the SIA 416 standard: gross floor area, usable area, net area, storey by storey, with an explicit and traceable method. In front of a buyer, a bank or an expert, “238 m² gross floor area to SIA 416, detailed table attached” does not carry the same weight as “around 240 m²”.
Up-to-date as-built drawings
Floor plans, sections, elevations: documents that reflect the building as it stands today, conservatories, annexes and alterations included, not the state of the original building permit. This is the document systematically requested by the buyer’s architect, their general contractor, and later the municipality for a permit application.
A digital walkthrough with the BIMx file
The model exports to a BIMx file, which can be viewed free of charge on a tablet or smartphone. The buyer, or a remote buyer, walks through the property in 3D, measures a room themselves, checks a ceiling height, at any time of day and without tying up the broker. Between two comparable properties, the one that lets itself be examined wins.
A working base for the buyer’s project
This is often the decisive argument on an older property: the buyer is not buying the existing building, they are buying their project. With an Archicad or Revit model (or an IFC export), their architect starts the conversion study on the day of signing, without redoing a survey. The cost of the 3D survey becomes an asset handed over with the property.
A real case: the Geneva villa sold with its file
In early 2026, a Geneva property management firm commissioned us for the 3D survey and BIM modelling of a villa being put up for sale, in a file combining the transaction and works under a general contractor. The schedule was tight: the firm had to hand the contract and the works file to the buyers on a given evening. We delivered the drawings, then the model, sections, elevations and BIMx file the day before and on the day of that deadline. The following day, the firm confirmed that the sale and works contract had been signed. The survey file did not sell the villa on its own, but at the moment of signing it gave the buyers verifiable floor areas and a base on which to price their works. That is exactly its role: to take the last reasons to wait off the table.
Who this is relevant for
- Property management firms and brokers: on the older properties in the portfolio, the 3D survey sets the sales file apart and shortens the negotiation. The BIMx file is also a remote presentation tool for international buyers.
- Private owners: before handing the property to a broker, having up-to-date drawings and floor areas produced means selling on facts rather than on estimates.
- Heirs and estates: in an inheritance, nobody has the drawings and every heir has their own figure. A neutral, dated survey provides a common basis for the valuation, the division or the sale.
- Developers and investors on the buying side: the reasoning flips: demanding (or commissioning) a 3D survey before buying means pricing your works on the real building.
The right timing: before the listing, not during the negotiations
The common reflex is to wait until a serious buyer asks for it. That is the worst possible moment: ordering a survey in the middle of a negotiation adds one to two weeks to the calendar at the precise point when the file has to move forward, and signals to the buyer that the file was not ready.
The right sequence:
- Decision to sell → order the 3D survey, at the same time as the photos and the valuation.
- Assembling the file → drawings, SIA 416 floor area table and BIMx included in the sales file from the first circulation.
- Negotiation → every question about geometry and floor areas already has its answer; the discussion is about the price, not about the data.
For a villa, the site visit takes half a day to a day; the property can remain occupied during the scan. The complete file follows within 7 to 9 working days for a 200 m² villa, 8 to 10 days for 350 m².
What it costs, against what it unlocks
For a villa of 200 to 350 m², a 3D survey with BIM modelling comes to between CHF 2’250 and 3’150 before options, with drawings, sections, elevations, model (Archicad, Revit or IFC) and BIMx file included; the SIA 416 floor area table is added as an option (+10 %). A scan on its own, without a model, costs less; for a survey with BIM modelling, the minimum order is CHF 1’350.
Set against the price of a villa in Geneva or Vaud, that is a fraction of a percent, and far less than the first negotiating move that an incomplete file invites. For the detailed ranges by floor area, see our article How much does a 3D survey cost in French-speaking Switzerland?; for a figure on your own property, the configurator gives a quote in 2 minutes.
Frequently asked questions
Does the SIA 416 floor area table have official status? It is a technical document produced according to a recognised standard, with a traceable calculation method; it is neither an official cadastral survey nor a notarial valuation. In a transaction, it serves as a verifiable reference for the advertised floor areas; for cadastral matters, the official land surveyor remains the competent authority.
Does the property have to be empty for the scan? No. Laser scanning is carried out in furnished, occupied properties, at no extra charge; we simply coordinate the room-by-room pass with the occupant or the property manager.
What does the buyer actually receive? Depending on the package: floor plans, sections and elevations (PDF and DWG), BIM model (Archicad, Revit or IFC), BIMx file for the 3D walkthrough and, as an option, the SIA 416 floor area table. All of it can be passed on to their architect without conversion.
Is the model still useful after the sale? Yes, that is in fact its second use: the base for the conversion study, for requests for quotes from contractors and for the permit application file. The buyer acquires an asset, not a marketing document.
What lead time should I allow for a villa? 7 to 9 working days between the scan and delivery of the complete file for 200 m², 8 to 10 days for 350 m². Hence the value of ordering before the listing goes live.
Preparing a sale? Configure your survey online: quote in 2 minutes. Get a quote. For the full list of services: 3D survey + BIM modelling.