European timber design standards set out basic serviceability limit design criteria for single span, simply supported floors, but the rotational stiffness of the fixing system and two-way support possible with modern solid timber floors can significantly influence deflection and vibration response. In addition, the added mass due to the use of non-structural floor screeds has an impact on the dynamic behaviour. The objective of this research was to investigate the influence of modern timber fixing systems and added mass on the serviceability behaviour of cross-laminated timber (CLT) floors. This paper outlines experimental research on a laboratory-scale, CLT floor using alternative arrangements of self-tapping screws and brackets, simulating common CLT platform construction details. Both one and two-way span conditions were considered. The influence of added mass was also measured. Non-destructive tests were carried out in accordance with European Standard prEN 16929 guidelines, which included measuring the static serviceability deflection due to a 1kN load applied at midspan and the floors natural frequencies and mode shapes between 0-80Hz. The study found varying degrees of influence on the serviceability response of the floor depending on orientation, imposed load, fixing type and spacing. In the case of single span platform construction using only self-tapping screws, the screw spacing had negligible influence on the fundamental frequency. The addition of support brackets increased the fundamental frequency up to 6%, with 11% reduction in the static point load deflection. Introducing added mass reduced the fundamental frequency by over 25%.