Finite element modelling of sandwich structures is challenging due to their extensive heterogeneities as well as material nonlinearity. It is often difficult to find a general homogenisation rule and model to be applied to wide range of sandwich structure configurations. Moreover, mechanics arising from their layers of significantly different stiffnesses need to be accounted for. Shear-flexible beam elements coupled with computational homogenisation presents an opportunity to efficiently model sandwich structures, while simultaneously preserving resolution at the mesoscale. Computational homogenisation provides the constitutive behaviour to the macroscale beam elements through the use of an explicitly modelled representative volume element of the sandwich beam. Layerwise kinematics are then incorporated into the model to handle the different layers of a sandwich beam. The Direct FE2 computational homogenisation approach is chosen for this proposed model. Compared to conventional staggered solution schemes, Direct FE2, which is a monolithic scheme, is able to attain computational savings as only a single iterative analysis loop is required. Moreover, only two key steps are required to set up the model and they are both completed in the pre-processing stage. Results from modelling a foam core sandwich beam showed that the proposed approach is able to provide both the macroscale constitutive response as well as localised deformations at the mesoscale that are almost identical to the traditional, more expensive Direct Numerical Simulations (DNS). Moreover, the Direct FE2 model used only 23% of the time compared to the DNS.