Timber-concrete composite (TCC) ceilings build on the idea of making use of the advantageous properties of both materials symbiotically. While concrete, as the upper layer, is used to absorb the compression forces, wood is used in the lower layer to absorb the tensile forces. Many systems have been developed with special attention paid to solutions with both a continuous concrete and wood layer. This article introduces a new system developed with the primary focus set on the most efficient material use by introducing a free space between the concrete and the wood layer using special vault shaped moldings. The first part of the paper contains an introduction including a short overview of different embodiments of TCC floor systems. The second part focuses on the design of the new system and gives an overview of the estimated structural performance. In the third part the environmental performance of the new system is discussed in comparison to chosen existing systems focusing at the the whole life-cycle including a re-use (A-D).