An integrated research project on timber-concrete composite (TCC) floors in Australasia comprises of four primary objectives involving the University of Technology, Sydney; the University of Canterbury, Christchurch; and the University of Sassari, Italy together with several industry partners. New applications of timber in multi-storey buildings are being sought by the timber industry in both Australia and New Zealand. Current development and testing of medium to long span flooring systems are highlighted. A semi-prefabricated TCC floor system that is economical, practical and easy to construct is proposed. Four major phases of extensive investigations for short- and long-term, involving full scale T-strip floor beams are described. The experimental results of phase one, short-term monitoring of beams are reported and compared with a uniaxial finite element model which was specially developed for long-term and collapse analysis of TCC beams. Overall, the validations were found to have good accuracy except for some cases with acceptable experimental deviations. Other parameters observed were different construction variables and types of concrete.