The paper explores, experimentally and theoretically, the possibility of producing a novel cladding sandwich panel comprised of a low-density wood fiber (WF) core and faces made of wood-based panels. Tests on small specimens, using physical and optical devices, were performed for the basic mechanical characterization of WF. Shear modulus (G) was the main target; and values for a range of nominal densities (ρ) from 110 to 190 kg/m3 were obtained. Short term load tests on real scale WF sandwich (WFS) specimens of 3.2 m span were also performed. An initial simple analytical structural linear model, taking into account the shear deformation of the core, was used to evaluate the data obtaining a reasonable agreement. The results show that WFSs are a viable solution at least for claddings; special care must be taken, however, in the selection of the face panels due to the influence of hygro-thermal changes. The line of work is especially attractive as WF is a natural and sustainable product.