Financing a loft conversion: How to create new living space
29.04.2025
10
Minutes
Katrin Straub
Managing Director at nextsure
Unused space under the roof is wasted potential. A conversion not only creates valuable living space, but can also increase the value of your property by up to 15 per cent. But how can such a project be financed?
The topic in brief and concise terms
The cost of converting an attic averages €1,000 per square metre, but can vary significantly depending on the specification.
State funding, especially from KfW, can significantly reduce the financing burden through grants of up to 37,500 euros.
A building permit is usually required, and the residential building insurance policy must be adjusted after the conversion to avoid underinsurance.
Calculate costs realistically
The costs of converting an attic vary greatly and depend on many factors. A simple conversion can start at €5,000, while a full redesign with a bathroom and dormer windows can cost up to €100,000. Experts estimate an average of €1,000 per square metre for a high-quality conversion. For a building permit, which is often required, around 0.5 per cent of the total construction costs is incurred. Budget an additional two per cent of the total construction cost for an architect or structural engineer to safeguard the building work. A detailed cost breakdown is the first step towards solid construction financing. This planning not only secures the budget, but also forms the basis for applying for loans and grants.
Combine financing options cleverly
There are several ways to finance your attic conversion. Rarely is such a project paid for entirely from equity. A popular option is the building savings contract, in which you receive a low-interest loan after the savings phase. Alternatively, a special renovation loan is suitable, which you can often apply for easily online. For larger sums above EUR 50,000, a mortgage loan is usually the cheapest option, as your property serves as security. Combining different types of financing is often the key to success. This allows you to combine equity with a building savings loan and government grants. The right mix depends on your financial situation and the scope of the project, which is why a careful comparison of the terms is essential.
Maximise government funding
The state supports the expansion of housing, especially when energy standards are met. The Kreditanstalt für Wiederaufbau (KfW) is the main point of contact here. With the programme “BEG residential buildings (261)”, you can obtain low-interest loans of up to 150,000 euros and repayment grants of up to 37,500 euros. Subsidies are also available for individual measures such as new insulation. Another option is the KfW programme “Age-appropriate conversion (159)” if you want to create accessibility. It is important to submit the applications, before you start the construction work. Professional energy advice, which is also subsidised, helps you find the right programmes and meet the requirements. This secures you significant financial relief for your project, such as a new roof covering.
In-depth expertise: construction law and insurance-related aspects
Loft conversion is more than just a building project; it also has legal consequences. As soon as you alter the roof pitch or the floor area, you need planning permission from the relevant building authority. A building project without permission is considered unauthorised construction and can lead to heavy penalties. Our expert tip: be sure to clarify whether permission can be granted in advance with an architect. After the conversion, the value of your property increases, which requires an adjustment to your residential buildings insurance. Notify your insurer of the newly created living space to avoid underinsurance and ensure full protection. This protects your investment of several tens of thousands of euros in the long term.
Practical example: A sample invoice for your loft conversion
Imagine you are converting a 60-square-metre roof space. The total cost comes to EUR 60,000. Your financing plan could look like this:
Equity: EUR 10,000
KfW loan (BEG 261): EUR 50,000 at a favourable interest rate
KfW repayment subsidy (20 per cent): EUR 10,000
Thanks to the subsidy, your actual loan amount is reduced to EUR 40,000. This means you save EUR 10,000 of the total costs directly through the funding. Such a plan makes financing the conversion of the loft into living space much more manageable. A home improvement loan without a charge on the land register can be an alternative for smaller sums. This example shows how a well-thought-out strategy can significantly reduce the financial burden.
The final step: successful implementation and safeguarding
Once the financing is in place and the permits have been granted, the actual construction phase begins. Good site supervision by an architect ensures quality and adherence to the budget, which often amounts to tens of thousands of euros. Bear in mind that the external areas, as with a façade insulation, may also be affected. Once the work is complete, the building inspection takes place. Only then is the new living space officially usable. With solid financing and professional support, your loft conversion becomes an investment that adds value and is future-proof. Request your individual risk analysis now: Have your insurance situation checked free of charge and receive specific suggestions for optimisation.
More useful links
KfW provides detailed information on funding for energy-efficient refurbishment measures for private individuals in existing properties.
The Federal Statistical Office (Destatis) provides comprehensive statistics on housing in Germany.
The Federal Ministry of Finance provides information on tax relief for household-related services and tradespeople's services.
On Laws on the Internet, you will find the full Building Energy Act (GEG) on saving energy and using renewable energy in buildings.
FAQ
How much does a building permit for a loft conversion cost?
The fees for a building permit usually amount to around 0.5 per cent of the project's total construction costs.
Can I carry out the loft conversion myself to save costs?
Yes, doing the work yourself can save costs. However, tasks such as electrical work, heating installation or structural interventions should always be carried out by specialist companies to ensure safety standards and warranty claims are protected.
Do I need to adjust my insurance cover after the loft conversion?
Absolutely. The newly created living space increases the value of your property. Notify your buildings insurance of the increase in value to avoid a coverage gap in the event of a claim.
What role does an energy consultant play in financing?
A certified energy consultant is a prerequisite for applying for many KfW funding programmes. They confirm compliance with the energy standards and help you obtain the maximum grants.
What is the difference between a modernisation loan and property finance?
A home improvement loan is often intended for smaller amounts (up to around EUR 50,000) and does not always require an entry in the land register. A property finance package (mortgage loan) is for larger projects, usually has lower interest rates, but is secured against the property by a land charge.
When do I need to submit the application for KfW funding?
The application for funding must always be submitted and approved before construction work begins. Retrospective funding is generally not possible.
