How much renovation work is needed when buying a home and how do I assess it?

Systematic analysis: How to determine the true costs

The service life table as a basic tool

To objectively assess renovation needs , you need to know the technical lifespan of building components. A house isn't a static monument, but a system of components that wear out . Experts use lifespan tables (e.g., from homeowners' associations) to estimate renovation needs .

Here are the most important guidelines to help you estimate your renovation needs :

• Roof (tile/flat): 40 to 50 years (flat roof often only 25–30 years).
• Heating (oil/gas/heat pump): 15 to 20 years.
• Windows: 25 to 30 years.
• Electrical installations : 30 to 40 years.
• Facade (plaster): 30 to 40 years.
• Kitchen/Bathroom: 20 to 30 years.

If you want to estimate the renovation needs , compare the year of construction (or the year of the last renovation) with these values. A boiler from 2003 is technically at the end of its lifespan today (2024). To estimate the renovation needs , you must include the full replacement costs – regardless of whether the heating system is still working today.

Identifying the major cost drivers

Not every defect is equally serious. If you want to estimate renovation needs , focus on the "Big Four ": building envelope, heating, windows, and plumbing. An ugly carpet is cosmetic. A leaky roof is structural.

If you want to estimate renovation needs , pay particular attention to the building envelope. A facade renovation with insulation can easily cost 60,000 Swiss francs or more. Is the plaster cracked or peeling? To estimate renovation needs here , it's worth taking a look at the foundation. Damp damage is expensive. The roof is also a significant expense. If you see tiles that are shifting or moss growth, you need to factor in high costs when estimating renovation needs . A new roof, including insulation, can easily cost 80,000 Swiss francs. Anyone who forgets to include these sums when estimating renovation needs will later face financing problems.

Energy regulations and hidden costs

A modern aspect that is important when you need to estimate renovation requirements is the legal regulations ( MuKEn ). Many cantons prohibit the direct replacement of fossil fuel heating systems without measures to the building envelope.

If you see an old oil heating system, simply budgeting 20,000 francs for a new burner isn't enough to estimate the renovation needs . You might have to switch to a heat pump (around 40,000 francs) and replace the windows. To accurately estimate the renovation requirements , you need to be familiar with the current energy regulations in your canton. Don't forget the pipes either. Old iron pipes corrode. To estimate the renovation needs here , perform a pressure test (open all the taps). A complete pipe renovation can cost tens of thousands of francs.

The calculation method for laypeople

So how do you arrive at a specific sum? To roughly estimate the renovation needs , professionals often use percentage formulas based on the building's value.

• Good condition: approx. 0–10% of the purchase price (cosmetic work).
• Average condition: approx. 10–30% of the purchase price (heating, windows, bathrooms).
• Poor condition: over 30–50% of the purchase price (complete renovation).

Do you want more details? To accurately estimate the renovation needs , create a list.

• List all components .
• Note the age.
• Is the age greater than the useful lifespan? Use the original purchase price.
• Is the age less than the expected lifespan? Check the visual condition.

Anyone who proceeds in this way can objectively estimate the renovation needs . At the end, add a safety margin of 10–15% for unforeseen circumstances (asbestos, rotten beams), which is often forgotten when estimating renovation needs .

When you should consult an expert

Despite checklists, laypeople often reach their limits when trying to assess renovation needs . Dampness in the walls or structural problems are invisible to the untrained eye. If you're unsure or the house is very old, get professional help to assess the renovation needs . A building surveyor or architect will charge approximately 500 to 1,000 Swiss francs for an inspection. Compared to the costs incurred by misjudging the renovation needs , this is a small investment. The expert will spot thermal bridges and cracks, helping you realistically assess the renovation requirements and gather arguments for price negotiations.

Conclusion

assess renovation needs before purchasing a property is crucial for your financial success. While the purchase price is negotiable, renovation costs usually aren't. Those who are blinded by superficial appearances and forget to have the technical renovation needs assessed are walking into a cost trap.

Use lifespan tables as a compass. Be pessimistic in your calculations. It's always better to overestimate renovation needs and end up with money left over than the other way around. Buying a house without an honest assessment is a gamble.

If you are looking for support in assessing the building structure or need a professional second opinion to accurately calculate the investment required, Loft offers you sound analyses for this purpose.

Glossary

• Estimating renovation needs: The process of determining future costs for maintenance and modernization of a property before purchase.
• Service life table: An overview of the average technical durability of components (e.g. heating 20 years), essential to estimate renovation needs .
• Investment backlog: The sum of all neglected maintenance work from the past that the buyer must make up for.
• MuKEn : Model regulations of the cantons in the energy sector. They influence the costs when estimating the renovation needs of old heating systems .
• Provisions: Cash reserves that an owner must set aside to estimate and pay for future renovation needs (recommended: approx. 1% of the building value per year).