Million-pound potential in the property: What homeowners should know
Many Swiss plots with detached houses contain unused development reserves that can significantly increase the value of a property. Extensions, additional storeys, extra apartments, subdivision of the plot or a replacement building are only possible, however, when the building regulations, access, easements and financial viability all fit together.
Briefly explained
A large plot with an older detached house may be worth considerably more than the existing building suggests. The decisive factor is not only the current value of the house, but also the residential or usable floor area that could in principle be created under the zoning plan, building regulations and other applicable rules. A practical example published by VZ VermögensZentrum in 2026 identified additional development potential of more than CHF 4.5 million for an older property. This is not a general benchmark, however: many theoretical reserves cannot be realised economically because of distance requirements, the shape of the plot, protection requirements, access, costs or insufficient demand.[1][2]
Contents
Current findings: Why the issue is becoming more important
Rising land and property prices, housing shortages and the political objective of inward urban development are increasing the pressure to make better use of already developed plots. At the same time, many detached houses built between the 1950s and the 1980s are reaching an age at which major refurbishment, conversion or a replacement building must be considered.
Wüest Partner estimates that Switzerland has around 1.1 million detached houses. Approximately 886,000 of them are used as a primary residence. Detached houses account for about 60 per cent of residential buildings, but accommodate only around 27 per cent of the population. No more than two people live in approximately 52 per cent of detached houses.[2]
These figures do not mean that detached houses are generally being used incorrectly. They do show, however, that theoretical reserves may exist on numerous plots, particularly in the case of older buildings on large plots in well-connected and sought-after municipalities.
| Current observation | Meaning for owners |
|---|---|
| High land prices in central locations | Additional residential floor area that can be realised may have considerable financial value. |
| Many older detached houses | A conversion or replacement building should also be examined before a complete refurbishment. |
| Housing shortages in cities and urban areas | Several smaller apartments may be more marketable than one large detached house. |
| Inward urban development | Municipalities may support upzoning, densification and replacement buildings. |
| Rising residential property prices | Price growth for owner-occupied homes remained strong in 2026, which may make development reserves even more valuable.[3] |
| Demographic change | Owners are increasingly considering smaller, age-appropriate apartments and the development of their existing plot. |
What does development potential mean for a plot?
Development potential describes the difference between the current use of a property and the legally, technically and financially feasible future use.
For example, a plot may currently contain a detached house with 140 square metres of living space even though the applicable regulations would in principle permit an apartment building with several units. The difference represents a theoretical utilisation reserve.
Four levels of potential
| Level | Key question |
|---|---|
| Planning-law potential | Which use is permitted by the legally binding building and zoning regulations? |
| Building potential | What can actually be built, taking account of the shape, topography, distances and existing building? |
| Market potential | Which apartments or houses can be rented or sold at the location? |
| Financial potential | Does an appropriate added value remain after all costs, levies, taxes and risks? |
A common mistake is to consider only the permitted planning-law utilisation. A project may be legally possible but technically difficult or financially unprofitable. Conversely, an existing building may benefit from protected existing rights that allow characteristics that would no longer be permitted for a completely new building.
Which factors can increase the value of a plot?
Building zone and permitted use
The zoning plan determines whether a plot is located, for example, in a residential, mixed-use, central, commercial or agricultural zone. The municipal building regulations determine the permitted use, density, building height and form of development. Land-use plans are binding on property owners.[4]
Utilisation and building volume
Depending on the canton and municipality, the permitted development is governed by different ratios and requirements. Common examples include:
- floor area ratio,
- gross floor area ratio,
- building volume ratio,
- site coverage ratio,
- green-space ratio,
- permitted full storeys,
- façade or building height.
The terminology and calculation methods are not standardised throughout Switzerland. The current cantonal legislation and the legally binding municipal building regulations are always decisive.
Location and access
A large development reserve is particularly valuable if the plot is well connected and demand is high. Important features include:
- proximity to railway, tram and bus services,
- jobs and urban centres,
- schools and childcare,
- shopping facilities,
- vehicle access and parking,
- water, wastewater and energy connections,
- residential quality, views and sunlight.
Plot size and geometry
A large plot is not automatically easy to develop. A narrow, steep or irregular shape may make it difficult to position buildings, access roads, parking spaces and outdoor areas sensibly.
Upzoning or rezoning
If a plot is allocated to a zone permitting more intensive use, its value may rise significantly. A planned zoning change only becomes binding, however, once the complete planning procedure has been concluded and the new land-use plan is legally effective.
Seven ways to realise unused potential
1. Convert the attic
An attic that has not yet been fully used can provide additional living space. Ceiling height, natural light, thermal insulation, fire safety, access and whether the space counts towards the permitted floor area must be examined.
2. Create an ancillary apartment
Part of the house can be used as a separate apartment. This can generate rental income, support multi-generational living or provide a future care solution. The kitchen, bathroom, entrance, fire safety and parking must be clarified.
3. Build an extension
A side or rear extension can create additional living space provided that boundary distances, building length, building lines, green-space requirements and the permitted utilisation are respected.
4. Add another storey
An additional floor can be particularly efficient where land is scarce. Sufficient structural capacity, permitted height, fire safety, earthquake resistance and suitable access are required.
5. Construct a second building
On large plots, an additional residential building may be possible next to the existing house. Building distances, vehicle access, utilities, parking and the remaining use of the plot are decisive.
6. Subdivide the plot
Subdivision may allow an undeveloped part of the plot to be sold or developed separately. Both new plots must function sensibly from a legal, technical and financial perspective.
7. Construct a replacement building
The existing house is demolished and replaced by a denser development, such as an apartment building containing rental or owner-occupied apartments. This option may create the greatest value, but it also involves the highest costs, risks and time requirements.
Other models without a complete sale
- grant building rights to an investor,
- develop jointly with a neighbouring plot,
- enter into a project partnership with a developer,
- sell individual condominium units after development,
- transfer the property to descendants with a clear development strategy,
- sell after obtaining a feasibility study or planning permission.
How is the utilisation reserve assessed?
An initial rough assessment compares the permitted development with the existing building. The calculation differs from one municipality to another and should therefore not be based solely on a general online formula.
Simplified example
Assume that a plot covers 900 square metres and the applicable rules permit, in simplified terms, 540 square metres of chargeable floor area. The existing house uses 180 square metres of chargeable floor area.
| Simplified permitted floor area | 540 m² |
|---|---|
| Existing chargeable floor area | 180 m² |
| Theoretical reserve | 360 m² |
These 360 square metres are not guaranteed additional living space. Staircases, technical rooms, walls, distances, parking spaces, building position, roof shape, topography and other requirements may significantly reduce the area that can be realised in practice.
Documents for the initial assessment
- address and plot number,
- current land-register extract,
- cadastral or site plan,
- zoning plan and municipal building regulations,
- public-law restrictions on landownership register extract,
- existing building plans and previous permits,
- information about easements and land charges,
- building lines and watercourse distances,
- register of contaminated sites,
- protection inventories and natural-hazard maps,
- information about access and utility lines.
The national Cadastralinfo service allows an initial search using an address or plot number. Detailed ownership information is available from the responsible land registry.[5]
What can limit the potential of the plot?
| Restriction | Possible effect |
|---|---|
| Boundary and building distances | Reduce the usable building area or prevent a second building. |
| Building lines | May exclude parts of the plot from development. |
| Easements | Rights of way, utility rights or building restrictions may limit development. |
| Historic-building or townscape protection | May restrict demolition, design or building volume. |
| Tree protection and green-space requirements | May require certain trees or open areas to be retained. |
| Watercourse space | Restricts development along streams, rivers and lakes. |
| Contaminated sites | May result in investigation, remediation and additional costs. |
| Natural hazards | May require protection against flooding, landslides or other hazards. |
| Noise protection | Influences room layout, ventilation, façades and the ability to obtain planning permission. |
| Unfavourable plot shape | Reduces efficient development despite a theoretical utilisation reserve. |
| Insufficient access or utilities | May require additional access roads, utility lines or land rights. |
| Neighbouring rights and legal remedies | May delay a project or require changes. |
Protection of existing rights can be valuable
An existing house may stand closer to the boundary, be taller or have a greater building length than would be permitted under current law for a new building. If it is completely demolished, this advantage may be lost.
Before a replacement building is planned, it should therefore always be examined whether:
- a conversion retains more usable area,
- an additional storey is possible,
- the existing building can be partially incorporated,
- a new building genuinely permits greater utilisation.
How is the financial potential calculated?
The financial value of a plot is not determined solely by the number of possible apartments. Expected income or sales proceeds are normally compared with the full development costs and risks.
Simplified residual-value method
The basic principle is:
minus construction costs
minus planning and approval costs
minus financing costs
minus marketing and selling costs
minus levies and taxes
minus risk allowance and developer’s profit
= financially supportable plot value
Fictitious example
| Expected sales proceeds from the completed units | CHF 6,000,000 |
|---|---|
| Construction, demolition and external works | – CHF 3,100,000 |
| Planning, approvals and specialist planning | – CHF 450,000 |
| Financing and marketing | – CHF 300,000 |
| Risk, contingency and developer’s profit | – CHF 750,000 |
| Simplified supportable plot value | CHF 1,400,000 |
The example shows that a project with sales proceeds of six million francs does not mean that the plot is worth six million francs. A large proportion is required for construction, planning, financing, risk and taxes.
Costs that are often underestimated
- demolition and disposal,
- hazardous materials such as asbestos,
- ground conditions and slope stabilisation,
- underground parking and parking spaces,
- utility connections,
- architecture and specialist planning,
- fees and replacement levies,
- interim financing and construction interest,
- objections and project delays,
- planning gain levy and property gains tax,
- sales or letting risk.
Develop it yourself, sell part of it or sell the entire property?
| Option | Advantage | Risk or disadvantage |
|---|---|---|
| Sell the existing house unchanged | Faster and simpler sales process. | The development potential may not be fully reflected in the price. |
| Potential analysis before sale | Interested parties receive a transparent development basis. | The study costs money and does not guarantee planning permission. |
| Prepare a preliminary project | Building volume, number of apartments and financial viability become more specific. | Planning work without a guarantee of a higher selling price. |
| Obtain planning permission and then sell | The buyer’s planning-permission risk is reduced. | Time, planning costs and legal-remedy risk remain with the owner. |
| Subdivide the plot and sell part of it | The owner may remain in the existing house. | Privacy, views and the quality of the remaining plot may be reduced. |
| Develop jointly with a developer | A greater share of the value creation may be possible. | Complex contracts and shared project, financing and market risks. |
| Self-development | Maximum control and potentially the greatest value creation. | High capital requirement, expertise, time commitment and considerable risk. |
| Grant a building right | The land remains in the owner’s possession and generates ground rent. | Long-term commitment and demanding contractual arrangements. |
Compare several offers
Property developers may offer very different prices because they use different assumptions concerning utilisation, construction costs, selling prices and risk. Owners should therefore compare not only the amount offered, but also:
- Is the price fixed or dependent on planning permission?
- How long is the property tied up exclusively?
- Can the buyer withdraw without cost?
- Who pays for planning and investigations?
- When is the purchase price due?
- Are additional payments due if greater utilisation is approved?
- Who bears the planning gain levy and other costs?
- What happens in the event of objections or delays?
Planning gain levy, property gains tax and other tax issues
Planning gain levy on planning-related increases in value
If a government planning measure creates a substantial increase in the value of a plot, a planning gain levy may be payable. Federal law generally requires compensation of at least 20 per cent of the planning advantage where land is newly and permanently allocated to a building zone.[6]
The rules for upzoning and rezoning differ between cantons and municipalities. In the Canton of Zurich, for example, municipalities may provide for a municipal planning gain levy for certain upzonings and rezonings.[7]
Property gains tax
A gain made on the sale of a property or part of a plot is taxed. The federal government does not impose a separate property gains tax; taxation takes place under cantonal or municipal law.[8]
The following factors typically affect the tax:
- sales proceeds,
- original acquisition price or eligible substitute value,
- value-enhancing investments,
- estate-agent, notarial and other selling costs,
- period of ownership,
- cantonal or municipal tax rate,
- possible tax deferral in the case of replacement acquisition.
Partial sale or subdivision
If only part of the plot is sold, acquisition costs, investments and other values must be allocated appropriately. This may affect the future taxation of the remaining plot.
Professional property trading
Anyone who systematically develops and subdivides a plot and sells several units with the intention of making a profit may, for tax purposes, no longer be regarded as merely managing private assets. The assessment depends on the circumstances as a whole. Before undertaking a larger self-development project, a binding tax review should therefore be obtained before contracts are signed.
Include financing and the mortgage at an early stage
An existing mortgage does not automatically disappear when a plot is subdivided or developed. The financing bank must generally approve a subdivision, a new mortgage structure or additional financing.
Important questions for the bank
- How is the current mortgage secured against the property?
- Which new plot carries which debt after subdivision?
- Will additional equity be required for the building project?
- How will the construction loan and later mortgages be structured?
- Will early-repayment penalties arise?
- How will the project be valued during construction?
- Which contingencies does the bank require for cost overruns?
A positive feasibility study is not a financing commitment. In addition to the plot and project, banks assess income, equity, advance sales, construction costs, marketability and the experience of the project partners.
Property potential in inheritance and succession planning
In an inheritance, a property may have a significantly higher development value than the previously assumed value of the house. If this difference is not recognised, unfair transfer values or later disputes may arise when the estate is divided.
Clarify before transfer
- current market value of the existing property,
- theoretical and realistic development value,
- refurbishment requirements and demolition costs,
- latent property gains tax,
- mortgage and financial affordability,
- residential or usage rights of the existing owners,
- the interests of all heirs,
- possible future subdivision or development.
A high potential valuation is not automatically the correct value for an intra-family transfer. Nor should only the value of the old building be considered. A transparent valuation using several scenarios is advisable.
Step by step: How homeowners can assess the potential
- Obtain the plot number, cadastral plan and current land-register extract.
- Check the zoning plan, building regulations and applicable utilisation ratios.
- Review the public-law restrictions register, building lines, protected objects, contaminated sites and natural hazards.
- Determine the existing floor area, building volume and current utilisation.
- Analyse easements, rights of way, utility rights and mortgages.
- Outline several options: conversion, extension, additional storey, second house, subdivision and replacement building.
- Arrange an informal preliminary enquiry or building consultation with the municipality.
- Commission an architectural feasibility study.
- Estimate market values, achievable rents or selling prices realistically.
- Calculate construction, demolition, planning, financing and marketing costs.
- Review the planning gain levy, property gains tax and other tax consequences.
- Involve the bank and mortgage provider at an early stage.
- Compare self-development, partial sale, building rights and complete sale.
- When selling, obtain several offers from investors and estate agents.
- Have contracts reviewed legally and for tax purposes before signing.
Typical starting situations in practice
Example 1: Large plot with an old house
A detached house from the 1960s stands on a large plot in a well-connected location. Instead of a complete refurbishment, the owner examines whether an apartment building is possible. The potential value depends on how many apartments can actually be approved and constructed economically.
Example 2: Subdividing the garden
An owner wishes to remain in the existing house and sell part of the garden. Before subdivision, access, utility lines, distances, privacy, the mortgage and the remaining utilisation of the original plot must be clarified.
Example 3: Additional storey for the next generation
The parents live on the ground floor, while an additional apartment is to be created for an adult child. Adding another storey may work if the structure, height, fire safety and access are suitable.
Example 4: Sale to a property developer
Several property developers make different offers. One high offer is entirely dependent on future planning permission, while a lower offer is binding. The decisive factor is therefore not only the figure on paper, but also the enforceability of the contract.
Checklist: Does my plot have unused potential?
Legal basis
Plot and building
Financial viability
Decision and contract
Frequently asked questions about property development potential
Sources and date of information
The article reflects the information available up to 30 July 2026. Planning, building and tax law differ between cantons and municipalities. The specific situation must therefore always be examined for the individual plot.
- VZ VermögensZentrum: Millionenpotenzial im Garten – viele Häuser sind deutlich mehr wert als erwartet, 22 May 2026
- Wüest Partner: Development potential of detached-house plots, updated 23 March 2026
- UBS: Price developments on the Swiss property market, 2026
- Geodienste Switzerland: Cantonal and municipal land-use planning
- Swiss Confederation: Cadastralinfo – access to property information
- Federal Office for Spatial Development: Planning gain levy under Article 5 of the Spatial Planning Act
- Canton of Zurich: Planning gain compensation for new zoning, rezoning and upzoning
- ch.ch: Taxes on property and property gains
- ch.ch: Information about building land, the land register, cadastre and zoning plans
- Federal Office for Spatial Development: Second stage of the Spatial Planning Act revision
Summary
A large or underused plot may contain considerable additional value. Older detached houses in well-connected locations with strong demand and generous plots are particularly interesting. The theoretical potential is derived from the difference between the existing development and the legally permitted use. It can only be realised, however, if distances, building height, access, plot shape, easements, protection rules and financial viability all fit together. Before refurbishment, inheritance or sale, owners should therefore first check the planning-law basis and have several options calculated. Only a feasibility study including costs, market conditions, financing and taxes can show whether the property genuinely contains potential worth millions or merely a theoretical utilisation reserve.