Build a dorm yourself

Dormers change the appearance of a house significantly. In attics you create a much more comfortable atmosphere by the daylight. For home improvement, self-construction of a dormer was one of the most demanding activities. Afterwards we offer you a detailed instruction so that you can build your dorm yourself.

There are many reasons for installing a dormer

Dormers are mainly installed because they flood the attic apartments comfortably with daylight. But also optical reasons speak for the installation of dormer windows, since they change the appearance of a building significantly. However, it is important to find the right measure. Too large dormers dominate, too small dormers are not very noticeable and do not offer the hoped-for benefits.

The different dormer versions

Therefore, before building a dormer you should be intensively concerned with the later appearance. Since you have to call in an architect or structural engineer anyway, it's worth going to an appropriate office. In addition, you should also deal with the various types of dormers.

  • Flat roof and tow dormer
  • arched dormers
  • triangle dormer
  • trapezoidal dormer
  • Walm and Krüppelwalmgaube
  • Bat dormer and ox eye

Build a dorm yourself: build

Important distinctions on dormers are also the versions. Some get along without cheeks, such as ox-eye and bat-dormer.

Dormers completely build yourself or prefabricated dormers

You can either build your own dormer yourself or purchase it as a kit or prefabricated dormer. The latter embodiments have the advantage that usually the necessary documents for the building permit are supplied.

After the roof truss has to be partially removed for the dormer, this affects the statics of the entire roof truss. Thus, dormers are subject to approval and a corresponding plan of the structural engineer or architect must be submitted.

The big sources of error in dormer construction


If you want to build the dormer completely yourself, you have to connect squared timbers for the front and the cheeks. Here must necessarily have a corresponding seal or adhesive in between. The dormer must be built completely airtight. Also when connecting the parts you have to proceed and seal everything accurately.

Standing water in the outdoor area

With many self-built dormers, this is where big problems arise. The result is penetrating cold, moisture and also ice inside the dormers. Another big problem for beginners is the covering after completion of the work. Often rain or melt water collects and can not drain away. But also snow can catch unfavorably at the dormer.

Reinforcement and substructure of the roof truss

An enormous challenge is the strengthening of the roof truss, ie the purlins and rafters. In any case, you will have to remove rafters to reinforce them around the new roof opening. In many cases, but also the much more delicate purlins. In any case, the roof truss must be professionally supported before cutting the opening.

Building material in the construction of dormers

The instructions for this are stated in the blueprint. Just as you pull up the front below the dormer inside. As dormer materials are different products in question.

  • OBD plates
  • external insulation
  • Siding
  • internal insulation
  • vapor barrier

Different constructions

The dormer itself can be constructed conventionally or ventilated. Which variant you should choose depends strongly on the individual conditions on site. It is also crucial to what extent the material used is permeable from the inside to the outside. Simply using the material that is perhaps the cheapest or easiest to process is therefore not possible.

Building dormers is professional work

These are numerous reasons why you should only approach the self-construction of a dormer, if you are actually so skilled in craftsmanship that you know the physical and thermal rules well - as a buzz word, whether and how open to diffusion from the inside to the outside Dormer should be and allowed.

All individual parts are also absolutely tight to connect with each other. That's why you should always carry out an air resistance test. Preferably, before attaching the vapor barrier and possibly again afterwards, so as not to identify imperfections faster.

After installing the new dormer

Once the vapor barrier has been installed, you can hear the further interior work as you wish. For example, dress with plasterboard.

Tips & Tricks

In any case, you should always seek expert advice if you want to build your first dorm yourself. The danger of mistakes, which are very costly in hindsight, is just too big.

Naturally, you will also find numerous interior design articles in the house journal, including [interior construction with plasterboard panels] or [plastering of plasterboard panels].

Video Board: Making Dorm Decor from Ikea Items!