In this contribution a strengthening technique applied at the intrados of timber floors, aimed at reducing their deflection under vertical loads is presented. The proposed technique is based on the use of traditional structural concepts and compatible materials, like wood and stainless steel strips. It consists in positioning aligned timber ashlars forced against the main timber beams by wooden shaped wedges, connected by a continuous stainless steel strip at their base. The technique creates a compound girt in the middle span of the floor, orthogonal to the main beams, able to redistribute concentrate loads from a most loaded beam to the adjacent ones, thus realizing a pseudo-slab behaviour. The results of four-point bending tests on strengthened timber floors and the built-up beam are presented. The main execution phases of the strengthening technique are described and discussed in the paper.