New report: Biobased ribbed decks can provide huge CO2 savings in multi-storey housing

23 different combinations of biobased floor and ceiling build-ups have been tested to find the right solution for the Mini CO2 Multi-storey Housing in Wood project – A project we are working on together with ONV, Artelia, Blumer Lehmann, and Egil Rasmussen for Realdania By og Byg.  

This has led to a new report (led by Artelia) showing that in the majority of the CLT- and ribbed deck solutions it is possible to reduce CO2 Emissions up to 55-70 % in comparison to typical hollow-core slab solutions while complying with sound and fire requirements of the building regulations. 

Why test? 

Floors slabs in multi-storey housing contribute to a significant amount of a building’s CO2 footprint. To provide adequate sound insulation between floors, concrete, mineral wool, EPS and screed are commonly used in floor separations. As a result, the floor slab alone can account for up to 20% of a building’s total carbon footprint. 

Incorporating biomaterials into construction can be an effective way to lower emissions, but the building industry faces challenges related to knowledge and experience in this area. The aim of the report is therefore twofold: to explore the interdisciplinary obstacles associated with bio-based floor decks and to investigate the potential reduction in a floor deck’s carbon footprint when it meets building regulations requirements. 

The 23 decks 

The build-up of 23 different combinations of floor and ceiling build-ups, on two different loadbearing slabs have been tested; The ribbed deck with the visible timber beams and the massive CLT-slab, with suspended ceilings, tested at the Technical University of Denmark’s acoustics lab. Both impact sound and airborne sound were analysed, which are the two parameters specified in the building regulation requirements for storey separations.  

All 23 combinations were made in collaboration with Artelia. The performances are listed in the report.  

Find the full report via Realdania’s website 

Photo: Claus Fisker/Realdania By & Byg