Developments in military technology, particularly in bombs, affected the construction work carried out in the Viapori fortress after the Crimean War – buildings were expected to be bomb-proof. The target was also set in terms of finding more effective and economical construction techniques. Red brick, stone and wood used during the Swedish era were replaced with cement, concrete, iron constructions, sheet metal and bitumen.

Space, savings and the quality of being bomb-proof

As long as the intermediate floors of brick buildings needed to be supported by brick vaults, constructing barracks was a slow process and required a large quantity of bricks. By using steel structures, construction work could be speeded up. Towards the end of the 19th century, a new structure was introduced which enabled the construction of intermediate floors on top of steel beams. Window openings could be supported with steel-reinforced concrete beams instead of vaults. Thanks to the new structural solutions, windows could be made larger and intermediate floors thinner. Brick facades were left unrendered in order to save costs, with the Manège of the Military Museum providing an example of such buildings. Its roof truss structure was reinforced with iron, meaning that no columns were needed in the Manège, making it an open space where manoeuvres could be rehearsed unobstructed. A new construction method was also applied to boathouses. Construction proceeded quickly and economically as the wooden framework was covered with corrugated iron.