Significant losses have been incurred due to damage to nonstructural components within buildings in recent seismic events, even in instances where the structural systems have performed well. This observation warrants improving the methods currently employed in practice to design nonstructural components to resist seismic demands. Procedures to accurately predict elastic floor response spectra, which can in turn be used to infer the acceleration and deformation demands induced in the nonstructural components, form an important part of the design methodology. Prediction accuracy is often traded off for simplicity in current design practice due to limitations in the available resources for nonstructural component design. This study proposes to develop a practice-oriented modal superposition method to predict elastic floor response spectra that balances accuracy with simplicity. This method is applied to directly produce floor acceleration response spectra. Conversion from acceleration to velocity and displacement spectra is also explicitly considered. The proposed method is verified using earthquake records from case study buildings in New Zealand, as recorded by the GeoNet structural array.