Typical Swedish house, courtesy of Swedish Wood (“Att välja trä” – Svenskt Trä 2013)
We interviewed Anders Rosenkilde, chief of technical development for the Swedish Federation of Wood and Furniture Industry (in Swedish Trä- och Möbelföretagen -TMF) about facts and figures on timber building in Sweden.
Q1) What are the current trends in modern timber house construction in Sweden?
Approximately 10 000 single family houses are built every year and 95 % of those are built in wood: 80 % of is prefabricated (off-site) in 2D cassettes or 3D volumes while 15 % of the total is built on-site out of precut timber.
Approximately 45 000 apartments in multi-storey houses are built every year and 5 000 of these are built in wood. These are mostly prefabricated in 3D volumes (framing system) but there is an increasing number of houses built with CLT and glulam (post and beam system).
Q2) What is the age distribution of Swedish wooden buildings and how often are they being demolished?
This depends on the type of building and the quality of the wood. The mean life cycle for buildings in Sweden is around 100 year. It is mainly houses built during the 1950s to the 1970 that are being demolished nowadays, usually because of economic or technical reasons. Older houses, such as 100 years old timber houses are considered valuable and if well maintained, they are not demolished (their life length continues).
Q3) How much of load-bearing wood is recovered today and how is it used?
Generally wood is usually not recovered, it is burned for district heating and electricity. This happens with all type of wood because Sweden has a high capacity to incinerate wood and the efficiency to obtain electricity and heat is high, that is why burning wood for energy purposes is also considered a “recycling process” in Sweden.
Q4) Is it possible to use recovered wood in timber construction and how? Which are the main possibilities and obstacles using recycled and reused timber in structural applications?
Usually not possible due to building regulation and Construction Products Regulations, but a very small amount is recovered in small projects when there is less control.
Q5) Are there any examples of demountable timber structures in Sweden?
Most of the log-constructed houses are demountable. Buildings made from 3D modules for kindergarten, schools are sometimes leased for 5 to 10 years and then modules are rearranged according to the needs or moved to another site.