basement

The basement (UG) refers to the floor of a building that lies entirely or partially below the natural ground level. A distinction is made between fully underground basements and semi-sunken basement levels that can still receive natural light. Depending on the standard of finish and building code classification, the basement is used as storage space, a utility room, an underground garage, a hobby room, or-if there is sufficient ceiling height and natural light-as fully-fledged living space.

Basement, Cellar, and Souterrain: Distinctions

In practice, the terms basement, cellar, and souterrain are often used interchangeably, but they have subtle differences. The cellar lies completely below ground level and is usually used for storage, building services (heating, water supply), or as an underground garage. The souterrain is only partially below ground level, has window openings, and can be used as living space-typically found in Wilhelminian-style buildings. The basement is the umbrella term for all floors below the ground floor, regardless of their depth below ground level. For calculating living space according to the Living Space Ordinance (WoFlV), the decisive factor is whether the rooms are suitable for habitation (sufficient ceiling height, natural light).

In purchase agreements and property listings, the terminology is often inconsistent. Sellers or landlords sometimes use the term “living space in the basement” without verifying whether the rooms are approved as living spaces under building codes. Buyers should therefore always review the building permit documents and verify what use is approved for the basement-because basement rooms used as living space without approval can lead to regulatory requirements or obligations to restore the space to its original condition.

Calculation of Living Space and Usability of the Basement

Whether areas in the basement can be counted as living space depends on several factors. According to the WoFlV, areas with a clear ceiling height of less than 1 m are not counted at all, those between 1 and 2 m are counted at half, and those 2 m or higher are counted in full. From a building code perspective, it is also crucial whether the rooms are approved for residential use-which in Bavaria requires a window area of at least 1/10 of the floor area. A well-finished, semi-sunken basement with a ceiling height of 2.50 m and sufficient windows can constitute full-fledged living space and significantly increase the property’s value.

The energy efficiency of the basement is also relevant: Uninsulated basement ceilings cause significant heat loss and, since the Energy Saving Ordinance (EnEV) and the Building Energy Act (GEG), are subject to mandatory insulation requirements for certain renovation projects. Basement ceiling insulation costs €20-60 per m² depending on the method and pays for itself in just a few years through the savings on heating costs. We advise homeowners on which energy-efficiency measures in the basement are sensible and eligible for subsidies.

Renovating and Upgrading the Basement

Many single-family homes built in the 1960s-1980s in the Nuremberg region have unfinished basements that offer significant potential: Converting them into a hobby room, home office, guest area, or granny flat can significantly expand the usable space. Important considerations include moisture protection (external waterproofing, internal waterproofing, or a combination), adequate ventilation and heating, as well as building permits if a change of use (e.g., for residential purposes) is intended. We recommend planning the conversion with an experienced construction and building services engineer.

Special caution is required for buildings in flood-prone areas: In some Nuremberg neighborhoods along the Pegnitz River, basements can flood during heavy rainfall events. Here, backflow valves and lifting systems should be installed before the basement is converted into a living space. The City of Nuremberg’s Civil Engineering Office provides information on the flood risk for a specific location.

Practical Tip for Homeowners in Nuremberg and Franconia

In Nuremberg’s single-family home neighborhoods (Thon, Langwasser, Gebersdorf, Ziegelstein), many basements are either unrenovated or used solely for storage. A high-quality basement conversion can expand living space by 20-40 m² and increase the home’s value by €30,000-80,000-with conversion costs typically ranging from €800 to €1,500 per square meter. We take finished basement spaces into account when determining market value and recommend always considering the condition and potential of the basement as part of the property appraisal.

When planning a sale, it is sometimes worth investing in a simple, clean renovation before marketing the property-even a dry, bright, and tidy basement area presented as a hobby room makes a significantly better impression on buyers than a dark, cluttered basement and can disproportionately increase the achievable sale price.

Frequently Asked Questions

Does the basement count as living space?

Only if it is suitable for use as a living space and has been approved under building regulations. Requirements: clear ceiling height of at least 2.20 m (WoFlV standard), sufficient window area (1/10 of the floor area), approved use as living space. Basements that do not meet the standards for a living space do not count as living space.

Do I need a building permit for basement conversion?

In Bavaria, interior conversion without a change of use is generally exempt from the permitting process (Art. 57 BayBO). However, if a change of use (e.g., from storage to residential) occurs, a building permit is required. The Nuremberg City Planning Office provides free information regarding permit requirements.

How do I protect the basement from moisture?

Key measures: exterior waterproofing of basement walls (waterproof concrete, waterproofing membranes), drainage, interior waterproofing with waterproofing slurry, foundation waterproofing, and a functional basement drainage system. For damp basements, an analysis of the cause by an expert is always recommended before conversion-treating the symptoms without addressing the root cause leads to a permanent risk of mold. On average, professional exterior basement waterproofing costs €10,000-30,000 depending on the scope, but it is the most sustainable solution.

How does a finished basement affect the energy performance certificate?

A finished, heated basement increases the building’s heated floor area and is therefore factored into the calculation of energy demand. Depending on the basement’s insulation and heating standards, the energy consumption per square meter of the entire building may improve or worsen. A well-insulated, efficiently heated basement with modern heating technology improves the specific energy performance if it is integrated into the building standard at a reasonable cost. A poorly insulated basement, on the other hand, increases heat loss and worsens the energy efficiency class-which is a disadvantage when marketing the property. In practice, we recommend developing an energy concept before renovating a basement that considers basement ceiling, exterior wall, and floor insulation in conjunction with one another. In the Nuremberg metropolitan region, energy consultants from the Bavarian Consumer Advice Center are a cost-effective first point of contact for this planning.

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