Balconies are a common feature of the buildings of the late 1920s, and though used only exceptionally in earlier buildings, the construction principles are the same.
In buildings with joist frameworks, balconies are constructed of a concrete base supported by structural (supporting) iron bolted to the beams. Where the joist framework includes iron beams, the iron support is formed by simply extending these beams.
In the figure to the right, the balcony guard is shown as concrete, but in earlier buildings it is often made from iron railings.
Recommended literature in Danish:
Byggebogen: Jernbjælkelag, Blad 4 (1949)