The article presents a multifunctional characterisation of biocomposite materials through the systematic determination of physical properties. Two specimens were synthesised: a substrate comprising 100% straw (density 326.57±33.29 kg m⁻³) and the other composed of 70% straw and 30% sawdust (density 190.94±12.87 kg m⁻³) with the mycelium of a Schizophyllum commune Fr. 1815 strain. Mechanical characterisation revealed differential modulus values ranging from 166.75 to 587.87 kPa, with enhanced formulation demonstrating a 3.65-fold improvement, achieving 1 541.40 kPa (R² = 0.96-0.98). Thermal property evaluation employed the plane source methodology with uncertainties below 5%. Both specimens exhibited exceptional thermal insulation with conductivity coefficients of 0.0477±0.0008 and 0.0480±0.0011 W m⁻¹ K⁻¹. Statistical analysis confirmed no significant difference (t = 0.3870, p = 0.7046), with variation coefficients of 1.57 and 2.34%. Thermal diffusivity reached 0.128±0.0043 × 10⁻⁶ m² s⁻¹ and 0.130±0.0042 10⁻⁶ m² s⁻¹ (p = 0.7404). Electrical characterisation across 40 to 110 MHz revealed frequency-dependent transitions with exponential correlations (R² = 93.64 and 95.50%). Sample B demonstrated inductive characteristics up to 95.15 MHz transition frequency. Pearson correlation analysis established a strong negative correlation for sample A (r = -0.8361, p < 0.0001) versus a moderate positive correlation for sample B (r = 0.2461, p = 0.0004). These findings establish quantitative structure-property relationships fundamental to multifunctional engineering applications.