Hjorthagen

80 years of age, this icon of a building needed a full renovation of the facade. Aiming to comply with the original building materials, lime based mortars were used

Stockholm

Sweden
Stockholm
Contractor
Kumla Fasad AB
Project Date
2010

Issues and stakes

The area of Hjorthagen, originally an island, used to be the hunting grounds of the Swedish King. Today it is known as the first industrial suburb of Stockholm, dating back to the late 1880’s. Workers in the harbour and the power plant in the area were the first inhabitants of the area. The development of the area started in earnest in the 1930’s. Some of the houses are of a lamella type (Olle Enquist), influenced by the German standards of that time, with the aim of space efficient use of the land. This is also known to be the first planned large scale construction of mass-produced and similar buildings. It also incorporated an architectural experiment with the location of the houses for best the sun conditions. Industrial construction methods were introduced in the building of some the houses in Hjorthagen. After 80 years of random repairs and painting,  a complete renovation was needed.

Achievements

The construction material is brick, originally with lime mortar, with a small amount of cement added. Modern lime-cement based mortars are not compatible with the strength and flexibility of the original materials. A premixed NHL-based product range was therefore chosen for this renovation, apart from the use of a fine, lime-based render and pure lime paint with non-organic pigment. The buildings were  in such bad condition that complete removal of the old render was necessary. A partial repair was considered uneconomical, as several layers of organic paint also covered the surfaces.  Such removal always includes repairs of the substrate, re-pointing joints with NHL based mortar and replacing damaged bricks. It is important that the process takes into account the long carbonation process of lime and avoiding plastic fissures that can occur in the early stages of hardening. After re-pointing, the three-layer render is applied: the thin strong primer, followed by a thicker and weaker base coat and the thin and weak final/smoothing coat. After  a certain hardening time, the application of the lime paint can start. For such an extended building, careful planning of the painting task was required to avoid visible drying seams.