Wood-cement compounds (WCCs) have been being used in construction since the beginning of the 20th century, mostly as a secondary structure or finishing layers such as sound or thermal insulation elements. However, WCCs’ stiffness and strength are rather low, therefore WCCs should be combined with timber or a similar light-weight structural material used as a load-bearing element. The use of WCC for composite elements allows to take advantage of both materials, particularly of the strength of timber and the insulation properties of WCC. Furthermore, WCC slab elements do only require a minimal secondary structure due to their beneficial sound and thermal insulation properties. This paper reports on a life-cycle assessment (LCA) where those new and promising composite slab elements have been compared to traditional concrete, wood and timber-concrete composite (TCC) slabs regarding greenhouse gas emissions (EGG), non-renewable primary energy (NRPE) and environmental impact points (UBP).