Czechia: Construction of taller timber buildings, it is useful to use materials other than wood

When building taller timber buildings, it is useful to use building materials other than wood, such as concrete or steel. The construction is then technically simpler, but it does not mean that it would be impossible to build a wooden building without these materials, said Petr Kuklík, head of the research department Materials and Structures of Buildings at the Czech Technical University in Prague (CTU). A change in legislation is currently being prepared that would allow multi-storey buildings to be constructed from wood up to 22.5 metres high. Currently, wooden buildings can be built up to four storeys and up to 12 metres high. This could change in the first half of next year.

"The moment a wooden building of a greater height starts to be constructed, it is convenient to use concrete and steel for its implementation. For example, make a timber-concrete ceiling, which is stiffer than pure wood, or reinforced concrete cores, which give the building good lateral rigidity and can accommodate lifts and staircases. There is also, for example, the use of steel weathering in the façade, which is more subtle than wood," said Kuklík. He added that while the construction of a timber building in combination with other building materials will create a hybrid form of timber building, if the building is at least half timber, it is called a timber building.
Currently, timber buildings up to 12 metres high can be designed and built under the Fire Protection Act 1985. Timber buildings can contain Class E insulants, a type that is capable of resisting the effects of a flame for a short period of time. Timber also falls into this category. Taller buildings are already required to contain A1 or A2 non-combustible insulants such as slats and mineral wool.

However, legislation is currently changing. For example, a change to the European set of technical standards was introduced in December last year. This makes it possible, for example, to better demonstrate the fire resistance of multi-storey timber buildings and therefore that they are a safer form of construction. Last July, Regional Development Minister Ivan Bartoš (Pirates) also asked Interior Minister Vít Rakušan (STAN) to reconsider the fire decree restricting the construction of wooden buildings. The Platform for Sustainable Construction from Wood, which brings together some development groups and banks such as UBM Development, Skanska, Trigema, YIT and Komerční banka, is also involved in the planned change of standards to allow for the construction of taller wooden buildings.

According to Kuklik, the market for wooden buildings depends mainly on investors. Multi-storey wooden buildings are a new type of construction, with which companies in the Czech Republic do not have much experience yet. When they get it, the price of these buildings, which is currently higher than for traditional brick buildings, could be reduced. According to Kuklík, the main advantage of wooden buildings is their fast construction, which can be almost a third lower than traditional construction. However, their low energy consumption could also increase interest among investors and buyers.

Source: CTK
Photo: ČVUT