Fast-growing pine wood modified by a two-step treatment based on heating and in situ polymerization of polystyrene

•Mass, strength and stiffness losses attributed to the thermal treatment were entirely recovered by the in situ polymerization of styrene;•The combined treatment also yielded increases in surface and volumetric hydrophobicity;•That wood treated by the two-step treatment showed high aesthetical attributes related to its dark surface colour;•The thermal treatment acted as a pre-treatment facilitating the post impregnation and retention of the polymeric substance. This study deals with a two-step treatment, in which a thermorretification at 180 °C for 2 h is followed by the in situ polymerization of polystyrene into a fast-growing pine wood. The treatment with polystyrene recovered losses in both stiffness and strength attributed to the thermal modification. Compared to the heat-treated wood, the two-step treated pine wood presented higher thermal stability (40%), termites resistance (8%), water uptake (300%), hydrophobicity, along with similar decay resistance, and surface colour and roughness.