Analytical solutions for two-dimensional steady-state and transient heat transfer from exterior ground surface are obtained for uninsulated slab-on-ground constructions. Approximate three-dimensional steady-state and transient heat transfer expressions are constructed. It is demonstrated that the approximate three-dimensional expressions give heat transfer results in satisfactory agreement with the analytical solutions and verified numerical models for the IEA BESTEST cases. The computation time for an annual simulation of the hourly floor heat transfer for the IEA BESTEST cases was found to be less than 0.1 s on a 2.6 GHz laptop computer. The proposed approximate expressions can be conveniently implemented in dynamic building simulation tools for fast ground-coupled heat transfer calculation. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.