In this paper finite element analysis of a five layer cross-laminated timber (CLT) rectangular floor is presented. The model was developed using 3D shell elements with linear elastic orthotropic material properties. Support conditions analysed included fully fixed, semi-rigid and simply supported, and both one and two-way span conditions were considered. For each case, the serviceability deflection was determined from a static small displacement analysis and the first three natural frequencies bending and torsional mode shapes, within a 0-80 Hz range, from mode frequency analysis. The analysis shows that the maximum displacement and frequency response are significantly impacted by the support stiffness and the number of edges supported. These results will contribute to determining the optimum fixing configuration with regard to serviceability limit design (SLD) for various CLT floor geometries.