How much is a dormer?

Dormers are a great way to bring light and air into an attic. Although they have a slightly lower incidence of light compared to roof windows, but in many cases provide a pleasant gain in space in the developed roof space. Read about the costs for roof dormers.


The details can be found in our service description.


Note that the quoted price example for a dormer is just a sample. Even with similar conditions, a dormer can cost significantly more or less, even with our sample versions, depending on the exporting company, there can be price differences of up to EUR 1,000.


Dormers are usually installed as prefabricated dormers in various forms today. Depending on the shape of the dormer, not only the incidence of light, but also the price is very different. There are also numerous design differences in detail:

Basic criteria for the dormer

Prefabricated dormers or dormer structures

In addition to prefabricated dormers, of course, individually planned dormers can also be installed. However, this creates a lot of effort in planning (individual planning for the building permit) and in the construction. The cost of such a special dormer can often be double to triple the price of a prefabricated dormer.

Special constructions

On the roof there are also many possibilities to use very special constructions. These include, for example:

  • Dacherker
  • a so-called Zwerchhaus
  • multi-storey Zwerchhäuser

Here is often already the planning of such a project very complex and expensive (usually architect planning required).

Dormer molds

Prefabricated dormers are available in a wide variety of shapes. The most widespread are:

  • towed dormers
  • triangular dormers
  • dormer windows (curved dormers)

The dormer shape plays (with the same size) a not insignificant role for the price. To make this clearer, we have different dormer shapes with the same dimensions (and execution details) as our sample dome can be calculated:

Our sample dormer (tow dormer)3.298 EUR
triangular dormer3.760 EUR
bats5.211 EUR
flat dormer2.870 EUR
Saddle Dormer3.652 EUR
Dormer Dormer3.788 EUR
Dormer Dormer4.162 EUR
Hedged Dormer3.924 EUR
Trapezoidal Dormer3.822 EUR

The prices are for reference only, as in our example. Depending on the provider, they can vary by up to EUR 1,200 in individual cases (even with a comparable version). The dormer shape related differences are clear in the table. (Prices are net prices)
Also note that not every dormer can be used for every roof pitch or roof construction.

Dormer dimension

dormer dimensions play an essential role in the price, the dormer height is often even more decisive for the price than the dormer width.

1.25 m high1.25 m high1.25 m high2 m high
1.5 m wide2 m wide3 m wide2 m wide
approx 6,400 EURapprox. 4,600 EURapprox. 6,400 EURapprox. 7,300 EUR

In our example of a (usual) towed dormer you can see the effects of different width and length of the dormer on the price. Decisive for the Gaubenmaß is in practice but then always the desired light and space gain.

Roof pitch of the dormer

The dormer itself may also have a different roof pitch. Lower roof pitches in the dormer usually do not lead to price differences. Occasionally for certain, desired inclinations only individual dormer forms are possible, which can then be more expensive in individual cases.

Basic criteria in the design details

Window in the dormer

The different types of windows used in dormer windows must also be taken into account:

  • U-value of the windows
  • Window shape
  • Rung frames, attachment frames

Either skylights or vertical windows can be used (depending on the model) Model of the dormer). There is also a clear price difference. Really finished windows are usually more expensive than windows with attachment rungs.

Covering the sides and front surface

The dormer side (dormer side) can also be glazed. This is usually found in prefabricated dormers but rarely. Usually forehead and cheeks are made with titanium zinc in different thicknesses.

Covering the dormer

The roof dormer must be covered on its roof surface with the same tiles as the rest of the roof. Accordingly, the costs for the covering of the dormer may vary depending on the existing roofing. Alone for the flat roof dormer (rarely used) a flat roof seal is used, which is usually a bit cheaper. The connection to the roof must be carried out professionally (throats sealing), so that the water drainage is ensured. This can cause higher costs in a particular case and thus a higher price when installing the dormer.

Costs for possibly additionally necessary work

Higher insulation in the dormer

If the thermal insulation in the area of ​​the interior trim is to be carried out to a higher value, this leads to a higher total price. If necessary, at higher insulation thickness then further adjustment work in the interior are necessary.

Installation of front roller shutter and sun protection

As with roof windows, a roller shutter or a special sun protection can also be fitted to the dormer. For the assembly then often a special effort is necessary (depending on the selected window and available accessories).

Additional sealing of the roof connection

The roof connection of the dormer must be able to guarantee a safe water drainage. Depending on the circumstances on site, additional work may be necessary.

Reducing factors

  • simpler windows, plastic windows
  • Reduction of the number of windows (single window instead of 2 or 3 windows)
  • No window rungs
  • Choice of a more favorable dormer shape

Increasing factors

  • Aluminum windows
  • Wooden windows
  • Really vaulted windows
  • Special function windows
  • Additional parts, such as shutters
  • Roofs outside the regular roof pitch
  • Roofs with high-quality coverings (must be continued on the dormer)

Saving options through self-construction or personal contribution

Only a specialist company (roofer) can install a dormer. This is the only way to ensure that the roof remains tight and there are no load bearing problems. Also in the subsequent interior design you should refrain from own work, as for a high level of experience is necessary. Failures in the area of ​​thermal insulation or inaccurate installation and connection of the vapor barrier can cause serious damage in the attic.

Funding Förder Funding may be possible in individual cases, especially if additional, energy-saving measures or an energy-efficient loft conversion are carried out during dormer installation. More information about possible funding can be found in our general funding overview.

Tips & TricksCompare the prices of different providers in each case carefully before you decide on a dormer model and a provider. When making the price comparisons, always make sure exactly what works are included and what services you may have to pay extra. Please also note that you always have to obtain a building permit for the installation of a dormer, as this is a significant change to the roof construction of the house!

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