Conservation of Tallinn seaplane hangars

Abstract

The roof of Tallinn seaplane hangars is among the first, remaining and still-preserved early large reinforced-concrete shells in the world. The hangars were constructed in 1916–1917 by the Danish company Christiani & Nielsen for Tsarist Russian military purposes. The roof consists of three 36·4 × 36·4 m spherical thin reinforced-concrete shells and seven 36·4 × 6·8 m short cylindrical shells attached to them. In 2010–2012, the seaplane hangars were completely renovated for the Estonian Maritime Museum. The high-quality conservation works received the Europa Nostra Grand Prix award in 2013. This study aims to give a comprehensive overview of the conservation process of the Tallinn seaplane hangars from a combined engineering and heritage protection perspective. The paper focuses on the conservation techniques and methods used and explains why and how such approaches were selected. The main findings of previous technical studies are presented to stress the critical technical condition of the hangars before the conservation process. A brief overview of the history of the building is also given, with an emphasis on the uniqueness of the Tallinn seaplane hangars in construction history.