Roof pitch

Roof pitch - The roof pitch (also known as the roof slope) indicates the angle of the roof surface relative to the horizontal. It is measured in degrees (°) and affects water drainage, snow load, the choice of roofing material, the usable living space in the attic, and the suitability for solar panels. Zoning plans often stipulate minimum and maximum slopes to preserve the character of the neighborhood.

Classification by Slope

• Flat roof: 0-5° - requires waterproofing instead of roofing, allows for a roof terrace and green roofing
• Gently sloped roof: 5-22° - limited material selection (metal roofing, bitumen membranes), limited use of the attic
• Moderate slope: 22-35° - standard for most roof tiles and concrete roof tiles, good rainwater drainage
• Steep roof: 35-60° - optimal use of space in the attic, high snow resistance, self-cleaning
• Very steep roof: Over 60° - typical for historic religious buildings and half-timbered houses, maximum attic height

Impact on living space and valuation

The roof pitch determines the calculation of living space in the attic according to the WoFlV: Areas under sloped roofs are only counted if the clear height is at least 1 m, and only half of the area is counted if the height is between 1 and 2 m. A steeper roof creates more space with full standing height and thus more countable living space.

Roof pitch is also crucial for solar systems: In Nuremberg (latitude approx. 49°), the optimal pitch for photovoltaic modules is approx. 30-35° with a south-facing orientation. Deviations of ±15° result in only minor yield losses of 5-10%.

Roof pitch and snow load

In Franconia, Nuremberg is located in snow load zone 1 according to DIN EN 1991-1-3 - with a characteristic ground value of 0.65 kN/m². For roof pitches of 30° or more, the snow load is significantly lower than on flatter roofs due to snow sliding off, which simplifies the design of the supporting structure and saves on steel. On roofs with a pitch of less than 15°, however, snow accumulates permanently, placing a greater load on the supporting structure and potentially leading to structural problems if calculations are inadequate.

In the higher elevations of the Franconian Jura-such as around Hersbruck, Neumarkt, or in the Nürnberger Land district-snow loads can be significantly higher than those in the city of Nuremberg due to the altitude and more frequent winter storms. Anyone purchasing or building a property in these regions should have the site-specific snow load zone verified by a structural engineer before deciding on a roof design.

Roof Pitch and Roofing Materials

Every roofing material has a standard roof pitch below which it must not be used without additional measures:

• Clay tiles (plain tiles): At least 22-30° depending on the type
• Concrete roof tiles: At least 14-22° depending on the type
• Slate: At least 25°
• Metal roofing (standing seam): From 5°
• Bitumen shingles: From 12-18°
• EPDM membrane / flat roof waterproofing: 0-5°

If the roof pitch falls below the standard, a substructure with a waterproofing membrane is required, which increases construction costs.

In Franconia, the flat-top tile has historically been particularly widespread-it characterizes the townscapes of many cities and villages from Nuremberg to Rothenburg ob der Tauber. Zoning plans in historic preservation districts often specify not only the minimum pitch but also the specific roofing material and color. Anyone wishing to renovate a historic building in Nuremberg’s Old Town or a Franconian town center should obtain the requirements from the local historic preservation authority early on, as non-compliant roofing must be removed at the owner’s expense.

Overview of Roof Shapes and Residential Use

In addition to the pitch, the roof shape also determines the usable space and roofing options. The gable roof is the most common shape in German residential construction: With a symmetrical pitch of 40-50°, the attic space provides sufficient volume for residential use. The hip roof-widely used in Franconia for prestigious villas and mansions-has sloped surfaces on all four sides; this results in less roof volume than a gable roof but a lower wind load. The mansard roof, with its angled surfaces (steeper lower section, flatter upper section), maximizes usable roof volume while maintaining a compact exterior silhouette-particularly advantageous in zoning areas with ridge height restrictions.

Practical Tip for Homeowners in Nuremberg and Franconia

We recommend that homeowners in the Nuremberg metropolitan area have the roof pitch accurately measured when planning an attic conversion-it determines the usable living space and thus the economic value of the project. With a pitch below 35°, the living space in the attic is significantly limited; at 40° or higher, the space becomes fully usable. Anyone planning a photovoltaic system should include roof pitch and orientation in the cost-benefit analysis-even on roofs with non-standard pitches or east-west orientations, PV is generally worthwhile, as yield losses compared to the optimal conditions are usually only 5-15%. In Nuremberg, the city promotes the installation of PV systems as part of the Solar Potential Cadastre, which is available online.

Frequently Asked Questions

What roof pitch does the zoning plan require?

Many Nuremberg zoning plans stipulate a roof pitch of 22-45° to maintain a uniform townscape. In the historic old town and listed ensembles, slopes of 40-50° with plain roof tiles are required. The exact values vary depending on the planning area-the specified values can be found in the plan drawing and in the textual provisions of the respective zoning plan, available for viewing at the Nuremberg City Planning Office. Anyone building in a planning area without a zoning plan must, pursuant to § 34 of the German Building Code (BauGB), align with the immediate surroundings-even there, de facto requirements for roof pitch may arise if the townscape features a uniform roof shape.

How does the roof pitch affect the roofing material?

Every roofing material has a standard roof pitch below which waterproofing measures (underlayment) are required. Concrete roof tiles and clay tiles require at least 22°, plain roof tiles at least 30°, metal roofing works from 5°, and bitumen membranes from 0°. Anyone wishing to install roofing below the standard pitch requires full-surface underlayment and, if necessary, a water-bearing layer-this increases costs and maintenance requirements. Especially for renovation and remodeling projects, it is important to involve the roofer early on so that the choice of materials is compatible with the existing pitch and no additional costs arise later.

Can I change the roof pitch later on?

Changing the roof pitch is a significant structural alteration that requires a building permit and must comply with the provisions of the zoning plan. The cost of changing the pitch-for example, by raising the roof truss-ranges from 30,000 to 80,000 euros for a single-family home. Such a measure only makes sense if it results in a significant gain of additional living space and the zoning plan permits it. In most cases, we recommend instead making the best possible use of the existing roof structure and expanding the available space by installing dormers-which are often approvable even for existing buildings in Nuremberg-without interfering with the load-bearing structure. Depending on their size and design, dormers cost between 8,000 and 20,000 euros and create additional usable space with full headroom.

Back to the Real Estate Glossary.