Construction cost of timber buildings

Rapport, 2022

There are increasing interests and practices in modern large timber constructions globally for the renewability and carbon storage function of wood. However, many stakeholders with limited knowledge and experience with timber still feel uncertain on how to carry out construction projects with timber. The common notion is that timber constructions would become more costly than a conventional alternative such as concrete. In order to inform wide spectrum of construction stakeholders in Scandinavia, this report presents a study on construction cost of cross laminated timber (CLT) buildings compared with concrete/steel buildings in Denmark, Norway and Sweden.

The study investigated the actual cost of 9 recent multi-storey residential buildings, 5 constructed with a load-bearing system in primarily CLT and 4 constructed in primarily concrete in Norway and Sweden. Due to the nature of the chronological and geographical differences of market conditions, the cost data were evaluated separately for Norway and Sweden.

In addition to the case building analysis, interviews were conducted with stakeholders from the case building projects as well as those from the industry with experiences with CLT buildings. The interviews contributed to a broader perspective of the cost analysis, with explanations of the projects and experiences of advantages and disadvantages for CLT building and concrete buildings.

The results showed a tendency that the construction cost of the Norwegian CLT projects were higher than the Norwegian concrete projects. For the Swedish projects the concrete building had a higher cost compared to the CLT projects, however it can't be concluded as a tendency for the Swedish projects, since investigation only included one concrete project and two CLT projects.

The results showed that often the material-related costs were higher for CLT buildings than concrete buildings. Such costs are for example the material cost itself and transportation cost for a long distance. Furthermore, the fire protection and measures for the finalized building according to fire safety resulted in a higher cost in the CLT cases. However, the construction time is often shorter for CLT buildings than concrete buildings, and CLT buildings are lighter and therefore the foundation can be dimensioned smaller. Although such observations were made, throughout the interviews it was stated that one should be careful comparing the cost of two buildings since the cost is very much depended on the specific project. Thus, the results shown in this report must be seen as tendencies and not as a forecast for specific cost difference between CLT building and concrete buildings.

This study was an investigation of construction costs and advantages and disadvantages of CLT buildings in relation to the construction cost up till 2022. When there is a major change in the economy and legislations of the construction sector, the cost structure may be substantially affected. One of such factors may be the increasing focus on the reduction of greenhouse gas (GHG) emissions from the construction industry. The availability of resource might be also a key factor for the future cost development for both CLT and concrete.