In brief

• The costs of electricity increased by 0.6 percent in September compared to August 2025 and were 19.1 percent higher compared to September 2024.
• Interest costs decreased by 18.7 percent between September 2024 and September 2025.
• Both the Contractors’ and the construction clients cost fell in September 2025 compared to August 2025. The decrease of the contractors’ costs was due to the fact the cost of building material decreased by 0.5 percent.
• Construction clients’ costs decreased by 7.3 percent in September 2025 compared to September 2024.

Changes in the last month

The Construction Cost Index for multi-dwelling buildings decreased by 0.3 percent between August 2025 and September 2025. This decreased was due to the fact that both the contractors’ costs and the construction clients’ costs decreased by 0.3 percent. These two groups account for 82 percent and 18 percent, respectively, of the Construction Cost Index.

Costs in the group ‘transport, fuel and electricity’ decreased by 0.1 percent. Within that group, the cost of electricity rose by 0.6 percent. The cost of transport and the cost of diesel oil decreased by 0.2 and 0.5 percent respectively. Contractors’ overhead costs decreased by 0.2 percent while costs for machinery and wages and salaries remained unchanged.

Contractors’ costs for building materials decreased by 0.5 percent in September 2025. Among the building material groups, the cost of wood work and electric material fell by 1.8 and 1.6 percent respectively. Pluming materials also fell by 1.2 percent. The only product type cost that rose was the cost of concrete products, that rose by 0.5 percent. The remaining material costs were unchanged or decreased by up to 0.4 percent between August and September 2025.

Construction clients’ costs decreased by 0.3 percent in September. Construction clients’ costs consist of interest and credit costs, costs for plans, and central administration. The decrease in construction clients’ costs was due to lower interest costs and cost of central administration, which fell by 0.4 percent and 0.5 percent respectively. 

Changes in the last year

The Construction Cost Index for multi-dwelling buildings increased by 0.2 percent between September 2024 and September 2025. Contractors’ costs rose by 2.4 percent, which led to an upward contribution to the Construction Cost Index of 1.8 percentage points. Construction clients’ costs decreased by 7.3 percent, which led to a downward contribution to the Construction Cost Index of 1.6 percentage points. The decreased construction clients’ costs was due to lower interest costs, which decreased 18.7 percent. The remaining construction clients’ costs increased by between 1.3 percent and 3.7 percent.

Contractors’ costs for wages and salaries and overhead costs increased by 3.5 percent and 2.8 percent respectively, while costs for machinery decreased by 0.8 percent between September 2024 and September 2025. Contractors’ costs in the group ‘transport, fuel and electricity’ increased by 3.6 percent. Within that group, the cost of diesel oil decreased by 1.4 percent while electricity and the costs for transport increased by 19.1 and 0.7 percent respectively.

Contractors’ costs of building materials increased by 1.9 percent between September 2024 and September 2025. All costs in the building material groups rose except the cost of electric materials, which decreased. The costs of wood products and materials for painting increased the most, by 9.5 percent and 10.7 percent respectively.