The paper outlines an experimental investigation, supported by analytical study, on the behaviour of round-wood timber-limecrete slab panels. Results from five panel tests using Douglas Fir poles and limecrete are outlined, accompanied by a programme of shear connector tests. Experimental results are compared with serviceability and ultimate limit state models. The study sets out to explore feasibility of round-wood and limecrete composite floors and validate existing analytical methods. The potential of limecrete to be a more environmentally benign replacement for concrete is also briefly discussed, together with the potential for wider development of timber-concrete or limecrete composites in the UK.