Finland

The wood apartment block in Postipuisto, Helsinki won the City of Helsinki’s Asuntoreformi architecture competition, aiming at exploring urban wood construction. This was the first project for A-Kruunu implementing CLT for the frame in a large urban residential block. The architectural design optimises the use of daylight for the interior and common areas and a greenhouse was provided in the exterior. According to the LCA calculation, the project has a reduced carbon footprint of approximately 20% over its life cycle compared to an average concrete building. To make sure the life cycle emissions stay low, the houses were built with a class A energy level target, which currently is best in class in Finland. In addition, A-Kruunu only uses green energy sources for heating and electricity. In addition to the reduced carbon footprint, A-Kruunu uses wood to create visibility and piloting opportunities for the wood construction industry in Finland. Crucial for the success of the project was the collaboration partner JVR-Rakenne with their wood construction and project management expertise. That also helped to stay within budget, which is especially important for A-Kruunu working the social housing field. The apartment rents are lower than market rents in the area, as targeted. At the same time, no compromises were made in the standard of living.

Life cycle modules 
[kgCO₂e/m² reference area * year]

Type of emissions
%

When do emissions occur?
[kgCO₂e/m² reference area * year]

The system boundary covers almost all life cycle modules, where the product stage is dominating the overall impacts, followed by repairs and replacements. Beyond the building materials, the assessment also includes a detailed inventory of building services (lifts and escalators, electricity system, renewable energy systems).
In the second figure, Operation includes B6, while materials include A1-A5, B4, C1-C4.
In the third figure, Upfront includes A1-A5, scenarios include B4, C1-C4, and D is shown separately.

GWP / reference area [kgCO₂e/m² reference area]

Material inventory: All materials
Life cycle modules: A1-A5, B4-B5, C1-C4

Waterproofing is included in the ground floor structure, finishes and coverings are included in walls, flooring is included in floor slaps, exterior cladding is included for the exterior walls and roof structure. The technical components included in this assessment have a total impact of 71.5 kgCO2e/m2 reference area (not included in the figure). 

Building element quantity / reference area [kg building element / m² reference area]

GWP of building element / building element quantity [kgCO₂e / kg building element]

■ Quantity/Area ■ GWP/Quantity

Material inventory: All materials
Life cycle modules: A1-A5, B4-B5, C1-C4

Building element quantity per building reference area is a measure for the material intensity, while element impacts per element quantity is a measure for the elements’ carbon intensity relative to their weight.

Product quantity / reference area [kg product / m² reference area]

GWP of product / reference area [kgCO₂e/m² reference area]

■ Quantity/Area ■ GWP/Area

Material inventory: Top 10 products with the highest impacts
Life cycle modules: A1-A5, B4-B5, C1-C4

Construction product quantity per building reference area is a measure for the material intensity, while product impacts per building reference area is a measure for carbon intensity.