Where can you find flat roof houses

The flat roof house - classic and ultra-modern

If you want to fulfill your dream of owning your own home and build a house, you can choose between many house types and roof shapes. A flat roof is suitable to avoid sloping ceilings. This is becoming increasingly popular as a feature of modern architecture. Technically mature, the flat-roof house offers many advantages for its residents. We'll show you which ones they are. And we give you tips on what you need to consider when building a roof terrace on your flat roof house, for example.

What is a flat roof house?

In general, there are two different roof types in modern architecture: pitched roofs and flat roofs. Houses with pitched roofs are characterized by sloping roof surfaces. Flat roof houses are buildings with a Roof pitch of 10 percent or less. The flat roof house has the advantage that the upper floor of a two-story house is fully habitable and usable. This is because the sloping ceilings in the rooms are no longer necessary.

There are many design options for a flat roof house. This can also be seen in our example flat roof house, which we will present to you in more detail below. The load-bearing construction of the flat roof house is neither complicated nor expensive. However, reliable and sustainable sealing and drainage on flat roofs pose challenges for many planners and architects.

The main advantages of the flat roof house are its compact shape. Because the flat roof house resembles a cube and has a smaller surface area compared to its volume. Accordingly, it offers a lot of living space. The more compact the shape of the building and the better you insulate your house, the less heating energy is lost through the outer shell.

Why flat roof?

In addition to the favorable shape of the building, there are other advantages in favor of a flat-roof house:

  • Installation of large window areas is possible on the upper floor
  • Maximum space: gain in living space and floor space on the upper floor by eliminating the sloping ceilings
  • offset building parts and recesses in the facade in the area of ​​the upper floor create space for balconies and roof terraces, green roofs are possible
  • exclusive, clear and modern look
  • based on the Bauhaus style, which represents timeless architecture

Ground floor plan: Flexible floor plan thanks to the flat roof: On the ground floor there is plenty of space for a terrace, which is also largely covered.

Floor plan first floor: The highlights on the upper floor are the open gallery that connects the rooms and the two balconies. Images: Wolf House.

Do flat roofs also have disadvantages?

When deciding on a design, you should generally also look at the disadvantages and be aware of them. Because no matter which design you choose - they all have their advantages and disadvantages. And only if you also look at the disadvantages will the planning be successful and you can realistically calculate all costs already at the design stage. So you first have to be aware that the flat roof house is more maintenance-intensive and consequently higher maintenance costs are incurred than with other roof shapes. A disadvantage in terms of load-bearing capacity is evident in winter: If there is an increased amount of snow, the residents have to shovel away the snow. Depending on where they live, builders are more or less affected by this disadvantage. Overall, however, the advantages clearly outweigh the disadvantages of the flat roof house.

What characterizes the Bauhaus style?

Sober, straightforward, reduced are typical terms that people associate with the Bauhaus style. An important basic idea of ​​this architecture is the famous expression "form follows function" - in German: The form follows the function. Cubic structures with a flat roof represent an essential feature of Bauhaus architecture, although the flat roof was not technically mature and not functional at the time. The modernists among architects stuck to it stubbornly - for aesthetic reasons. For them it was the symbol of progress.

The Bauhaus School only existed from 1919 to 1933. In this short time, however, it became the most important institution for architecture, design and art in the 20th century - and beyond. The university revolutionized the understanding of architecture worldwide - with a claim that is still valid today. Even if the Bauhaus concept is now over 100 years old, it has lost none of its topicality and attractiveness. Many modern flat roof houses are considered to be further developments of the then new objectivity. Based on the Bauhaus architecture, houses in the shape of a cube are also known today as cube houses.

Example flat roof house: Edition Select 236 from Wolf-Haus

There are also prefabricated houses that are characterized by their formal clarity and that have a flat roof. There are many possibilities here to reinterpret the classic. We show that at this point House Edition Select 236 of the prefabricated house manufacturer Wolf-Haus. The flat roof house consists of cubic shapes of different sizes that are designed differently.

Due to the height differences, they enable two balconies in the outside area and a roof over the terrace areas running along two sides. There is also a reduced formal language inside the house. The living and dining area is open and bright and offers opportunities for retreat. A special feature is the staircase that leads up to the gallery. Through the glazing it seems to float. The house can accommodate at least four people.

What are the special features of the flat roof?

A flat roof is constructed as follows: load-bearing structure, roof skin, seal, thermal insulation and drainage. And even a flat roof cannot do without a slope. Otherwise standing water would put a strain on the roof cladding of the flat roof house and shorten the service life of the entire roof structure in the long term. A gradient of two percent is therefore a minimum.

With an incline of three to five percent you are on the safe side. Then an effective runoff of the rainwater is guaranteed in all cases. There must also be sufficient drainage facilities. For this purpose, roof drains are installed at the lowest points of the roof surface, which drain the rain and condensation water. Your perfect connection to the roof waterproofing is essential.

How do I make sure the flat roof is waterproof?

While rain security is sufficient for a pitched roof, the flat roof must be absolutely waterproof. For this purpose, it has a layer that is impermeable to water. These are sheets made of bitumen, polymer bitumen, plastics or elastomers. Due to their greater thickness, bitumen membranes are extremely robust against mechanical impacts (e.g. hailstorms). Plastic sheets, on the other hand, can easily be adapted to the roof installations. And elastomer sheets are characterized by their flexibility and the possibility of individual, full-surface prefabrication.

How do I secure the flat roof?

A Attica prevents water from running off to the side on the flat roof. This means an edge on the roof that is higher than the flat roof. This roof edge is created in a timber frame construction and implemented as a circumferential, slight ceiling elevation. The end of the parapet consists of a sheet metal cover. In addition, the parapet optically conceals the required slope of the roof, which is often created by means of slope insulation.

As protection against solar radiation, wind suction and other damage, you can use a Layer of gravel raise. The parapet protects this layer from falling or being blown away. Disadvantage with gravel: it puts a lot of ballast on the roof and has to be considered statically. So the advantage is lost again that the roof load is lower in the flat roof house compared to the pitched roof with tiled roofs, which allows slimmer constructions. Since the sheeting is now more resistant to the effects of the weather, stones are often not used today. As with any roof, the flat version is the insulation an integral part of the design. It applies to the requirements of the Energy Saving Ordinance to be observed. There are three constructive principles here: warm roof, cold roof and inverted roof. The differences are illustrated in the graphics and in the tables.

The Warm roof is the classic flat roof. Construction from bottom to top: roof structure, vapor barrier, thermal insulation, waterproofing membrane, roof skin

construction of Cold badger from bottom to top: roof structure, vapor barrier, thermal insulation, air layer, roof waterproofing, upper structure, roof skin

construction of Inverted badger from bottom to top: roof structure, waterproofing membrane, thermal insulation, protective layer, roof skin

Properties of the flat roof house construction Warm roof

Properties of the flat roof house construction Cold roof

Features of the flat roof house construction inverted roof

What are flat roof tiles?

There are special flat roof tiles to cover flat roof slopes in a rainproof manner. However, they are not used in flat roof houses, but in flat pitched gable roofs. They are usually used with a roof pitch of 10 degrees or more. The bricks have longitudinal and transverse rabbets, which interlock precisely when they are covered. They also offer additional security against the ingress of moisture. Basically, a standard roof pitch is given for every roofing material. This describes the inclination that the roof surface to be covered needs at least so that the selected covering material guarantees the desired protection against rain.

What uses does a flat roof offer?

A five to 10 centimeter thick layer of gravel has proven to be the top top layer, but it is heavy and requires a correspondingly complex structure. The alternative is called a green roof, but it is always more expensive. Depending on the layer structure, intensive or extensive greening is possible. The latter only needs to be looked after from time to time in the first year. In contrast, an intensely green roof requires a lot of regular maintenance. The green roof scores with positive properties such as sound and heat insulation, improvement of the microclimate and storage of rainwater.

Some development plans prescribe the greening of flat or slightly sloping roofs. With the greening of a flat roof, you help to unseal the areas that are heavily sealed in cities by streets and buildings. It also holds back rainwater for a while after it has rained down. This relieves the public sewer system and improves the microclimate in the immediate vicinity of the house.

Even with a flat roof or slightly sloping roof surfaces, the generation of solar power possible. There are also special assembly systems for free-standing installation of the collectors. They consist of triangles that can be installed on most surfaces and all common roof structures. The triangles are made of sturdy aluminum profiles and are completely pre-assembled.

Anyone who wants additional light sources or another option for ventilation can Skylights build in. Skylights are also conceivable.

How much does a turnkey house cost?

The costs for a turnkey prefabricated house are made up of several aspects that can be roughly divided into four categories: these include the property costs, ancillary construction costs, pure construction costs and the costs for the outdoor facilities. All of these cost items are heavily dependent on the location in which the construction project is to be implemented. There are enormous price differences across Germany. In addition, it always depends on the size, the type of house and the features of the house. Anyone who wants to build a turnkey house must of course always expect a higher price from the prefabricated house manufacturer than is the case, for example, with a prefabricated house in the expansion stage.

What does a flat roof house cost?

The prices for a flat roof house with two floors are very different and depend on several factors. Above all, the living space, the expansion stage of the house and the building materials used are decisive. When it comes to the costs of the roof, the chosen construction method, the drainage system and the waterproofing play a role. The price for the thermal insulation and any rear ventilation are also included in the cost calculation. In addition, there is the necessary plumbing work and special equipment.

Flat roofs have to be well sealed because the lack of an incline means that rainwater only drains off gradually. Roofing membranes made of bitumen are suitable as sealing material, and these are of high quality from 7 euros per square meter. The material costs for plastic sheets are 5 to 12 euros, elastomer sheets cost from 10 euros per square meter.

On the pure Roof price related, the flat roof is only slightly more expensive than a gable roof. Only a monopitch roof is cheaper than a flat or gable roof. Hip or mansard roofs, on the other hand, are among the most expensive roof shapes.

What does a flat roof bungalow cost?

Flat roof bungalows were already very popular 50 to 60 years ago. Here, too, there are certain points that affect the cost of the prefabricated house. With the roof you have to include the costs for the flat roof structure, the drainage system, the ventilation and the flat roof windows.

As with flat roof houses, the cost of a flat roof bungalow always varies greatly and depends on many factors. It is impossible to generalize the price for the roof, as well as for the entire house. When it comes to the roof, the most important thing is the roof structure, the drainage system and the building materials used. In addition, there is the equipment of the bungalow, the cost of which varies greatly.

How do I create a roof terrace on a flat roof house?

A particularly popular use of the flat roof is the roof terrace. It has many advantages: It has excellent sunbathing, offers protection against the view from the neighborhood and in most cases guarantees a great view.

If you want to realize a roof terrace on a flat roof house, you have to catch up with one Building permit There are still a few things to consider when building. First of all, be aware that, for structural reasons, you have to take this type of project into account when planning the building. The building material used means a additional load. The situation is different with a green roof. In most cases, greening is possible retrospectively and is often used for renovations.

The roof terrace must withstand the weather in any case. It must be planned in such a way that it prevents water from penetrating the floor of the ceiling. The sealing standard DIN 18531 must be observed. To avoid standing water, the surface is sealed with bitumen or welding sheeting.

How do I make the roof terrace accessible?

It is important that the roof terrace is made accessible. This includes the right one Access to the roof. This should be covered and safe. This can be done, for example, via an internal staircase or ladder and a roof hatch with a sliding window or skylight. Alternatively, an outside staircase is possible. Depending on the orientation of your roof terrace, increased solar radiation can be expected. Make sure you have one Sun protection and optionally for a privacy screen.

To be safe, you need a Fall protection. This can be mounted on the parapet in the form of a railing or a narrow wall, for example. Finally, there is still the question of the covering: There are a wide variety of materials, such as natural stone slabs, exposed aggregate concrete, gratings or wood. Appropriate maintenance is necessary depending on the material.

Are flat roof houses suitable for plots on a slope?

Those who build on a slope can usually look forward to an unobstructed view. In addition, houses on the slope allow access not only on one floor, but from several levels. The location on the slope facilitates the provision of independent access routes. But a plot of land on a slope brings with it great challenges for statics and construction technology. It is therefore important that the soil conditions permit development. A Soil appraisal is recommended. So you know what costs you will have to pay for the development.

The architecture of flat roof houses is well suited for properties on a hillside. Here, for example, the construction of Terrace houses at. In this way, several floors can be stacked on a hillside. With this type of construction, each floor has its own terrace. The flat roof blends in perfectly and visually forms the perfect finish to the house. Terrace houses are also well suited for the installation of granny apartments. With this type of construction, flower troughs or sun protection slats act as privacy screens between the individual levels.

More house examples

Edition Select 236

Expansion stage: Finished house
Room: 6
Living area: 236 m²

Edition Select 187

Expansion stage: Finished house
Room: 8
Living area: 187 m²


There are many points in favor of a flat roof house. The biggest advantage of this design is that No sloping ceilings, which gives the residents more space. In addition, the flat roof can be used as a terrace, for greening or for the installation of a photovoltaic system. The timeless and clear architecture convinces many clients, also in the Prefabricated construction. In the construction methods of flat roof houses, a distinction is made between warm roof, cold roof and inverted roof. This is most common in flat roof houses Warm roof Use.

Anyone who builds a flat roof house has to pay attention to one thing above all else: The be-all and end-all of a flat roof is an absolutely watertight one construction as well as ventilation and drainage. With professional construction and the right material, the flat roof, like any other roof, will be safe and tight for decades.

KeywordsRoof shape, flat roof