Preparation of modified wood

Wood is modified by treating with an aqueous water repellent [I] and an emulsion water repellent [II]. The aqueous water repellent [I] comprises a product obtained through co-hydrolytic condensation of (A) an organosilicon compound: (R¹)_a(OR²)_bSiO_(4-a-b)/2 and (B) an amino-containing alkoxysilane: R³R⁴NR⁵SiR⁶_n(OR²)_3-n. The emulsion water repellent [II] is a trialkylsiloxysilicate emulsion water repellent obtained by polymerizing (C) an organodisiloxane: R⁷₃SiOSiR⁷₃ and (D) a tetraalkoxysilane: Si(OR⁷)₄ in an aqueous solution containing (E) a surfactant and (F) water. Two stages of treatment with repellents [I] and [II] can impart water repellency, minimal water absorption and dimensional stability to wood.