- Substantiate the expected additional proceeds using suitable apartments; construction costs are not an increase in value.
- Compare only additional costs and timing effects between the options.
- Clarify consents and building-law requirements before changing the layout, windows or services.
Which decision should the renovation make easier?
Define your sale objective, available budget and latest desired completion date. A vacant apartment with clearly visible renovation needs may appeal to buyers who want to choose their own layout and fittings. Other prospective buyers want a property they can use immediately. Which group is actually relevant to your apartment depends on factors including location, size and the appropriate market segment.
Also separate presentation problems from building problems. Clearing, cleaning, good documentation and an understandable floor plan can remove uncertainty without installing a new kitchen. A damp patch, by contrast, first requires investigation of the cause. Painting over it provides neither a reliable diagnosis nor a professional repair. Record known damage and investigations already carried out for the sales documents.
Compare clearly defined packages
Define only a few clearly distinguishable options. Each needs a specific scope of works: which rooms, surfaces and systems will be worked on, what will remain, and what result must be delivered? Otherwise, the general label renovated may describe very different conditions. For electrical work, for example, describe the scope checked rather than making a blanket promise of new electrics.
| Option | Typical scope | Key question |
|---|---|---|
| Document the existing condition | Documents, cleaning, defect reports | Can the buyer reliably assess the work required? |
| Carry out targeted repairs | Specific defects and selected surfaces | Will usability improve without a major follow-on project? |
| Modernise comprehensively | Coordinated interior works and fittings concept | Will the market support the total costs and timing risk? |
Which costs and prerequisites are easily overlooked?
Obtain quotations based on the same specification. Compare included quantities, disposal, substrate preparation, ancillary works, taxes and completion dates. A low flooring quote may exclude removal of old coverings; a bathroom quote may leave necessary pipework unresolved. For such items, ask for an investigation or an explicitly stated cost range.
Before alterations, apartment ownership law and building law must be checked separately. § 16 WEG governs, among other things, consents where other owners' legitimate interests may be affected. The type and scope of a Vienna construction project, in turn, determine the required building-law procedure. Information from the property manager cannot replace technical or legal assessment of a wall opening. Clarify these prerequisites before committing to construction and sale dates.
Foundations: RIS [1] · Stadt Wien [2]
How can the additional sale proceeds be substantiated?
Compare apartments with genuinely similar location, usability, building quality and fittings. The gap between an unrefurbished listing and a high-priced property marketed for first occupation does not yet prove an achievable renovation profit. For the sales comparison approach, § 4 LBG requires suitable purchase prices and transparent consideration of differences affecting value. This is also a useful guideline for your preliminary market review.
For each option, ask for a justified proceeds range and an estimate of marketing time. A new bathroom may suit different buyer tastes from those you expect. Conversely, eliminating a clearly identifiable technical uncertainty may make a decision easier without producing an exactly matching euro increase in price. Document the assumed buyer group and the comparable cases used.
Foundations: RIS [3]
Calculate limits and a stopping point
The central economic question is: additional proceeds minus additional renovation, ancillary and holding costs. Include only costs that actually change between the options as differences. Costs already incurred are generally not newly triggered costs for this future decision. Personal taxes and financing may affect the available net proceeds and are examined separately where differences are relevant.
Also calculate the minimum additional proceeds required and a less favourable option: what happens if construction takes longer, costs rise or the selling price is lower? Set a stopping point, for example if investigating causes reveals extensive additional works. For a later resale after modernisation, evidence of works, invoices and required completion documents belong in the property file. Verifiability is part of the quality of the sale process.
Fictional calculation: a higher selling price is not enough
An invented comparison for the same apartment available with vacant possession. Assumed proceeds in its existing condition: 300,000 euros; after a defined package: 335,000 euros. Both are purely scenario values, not Vienna market prices.
- The assumed additional proceeds are 35,000 euros. The package costs 24,000 euros, additional planning and ancillary works 3,000 euros, and additional holding costs 4,000 euros.
- This leaves 35,000 − 24,000 − 3,000 − 4,000 = 4,000 euros before further price, cost and individual tax effects.
- If the assumed post-renovation proceeds fall to 329,000 euros, the difference after the same additional costs is minus 2,000 euros. The calculated break-even point is 331,000 euros of post-renovation proceeds.
The small buffer makes the decision sensitive. Only reliable quotations and appropriate market evidence show whether modernisation justifies this risk.
Your next assessment steps
Record what you have already clarified and which documents you still need.
Define the sale objective and latest desired date
Shows whether a construction project fits the timeframe and cash resources.
Where can I obtain the supporting information?
Write down your own decision criteria before discussions.
Define the package of works with comparable quotations
Makes excluded work and possible variations visible.
Where can I obtain the supporting information?
Approach specialist contractors using the same specification.
Check technical causes and required consents
Prevents calculations based on an uncertain scope of works.
Where can I obtain the supporting information?
Authorised professionals, the property manager and the responsible building authority.
Calculate additional proceeds and delay as ranges
Shows the minimum additional proceeds and how robust the decision is.
Where can I obtain the supporting information?
Combine the cost framework with professionally justified comparable data.
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Sources and date
The following sources support this main article. For your specific property, current documents and the applicable conditions matter.
- RISApartment Ownership Act 2002 § 16: use, alteration and maintenance
- Stadt WienBuilding notification: type of building procedure and required permissions
- RISProperty Valuation Act § 4: sales comparison approach
Editorial date: 11/09/2026. Examples explain relationships and do not contain an individually prepared property valuation. Editorial work and sources.
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