Copenhagen roof

Building Type 1: 1850-1890

In principle, the Copenhagen roof shares the same strengths and weaknesses as other roof structures (saddle, gambrel, etc.). If a renovation/modernisation is to be carried out on an attic having a Copenhagen roof, e.g. by converting a box room into a living space, there are a few technical conditions that must be closely observed.  

As a general rule, the flat section of the roof must be raised to allow for adequate ceiling height in the roof space. This entails a raising of the roof structure as well as the gable/fire wall parapet and thus a change in the building’s appearance – both in itself and in relation to its surroundings.  

The sloping roof surface is insulated internally, while the flat roof section may be insulated either internally or externally – the latter is known as a “warm roof”, where the dew point of the structure lies outside of the wooden frame and where the impermeability requirement of the damp-proof membrane is easier to meet during construction. In the case of internal insulation solutions, the correctly planned and executed ventilation of the structure is an essential component.  

If the roof covering is to be replaced due to general wear and tear, there is a current requirement that this should be supplemented with a subroof solution. This is in order to ensure more comparable lifespans for the various parts and materials within the roof structure, thereby extending the lifespan of the roof as a whole.  

GODE TAGE | DK has a number of illustrated examples showing how a roof structure can best be constructed to achieve good durability. In addition, good advice on a selection of subroof solutions can be found on the DUKO | DK website. In addition, see BYG-ERFA: Subroofs and roof structures  

A newer solution for the replacement of slate roofs, which is not yet in general use but expected to gain in popularity, uses no lathing, meaning that the slate tablets are fixed directly onto the permanent subroof (see photo to the left).  

The BVB | DK website includes a number of general recommendations about roofing works based on many years of accumulated experience from publicly funded building renovation projects.  

Photos: sbs/Graves Simonsen