PURPOSE: To provide a manufacture capable of expanding the range of uses by using jointly an antiseptic agent other than resin as an impregnant although conventionally resin reinforced lumber is made by a method wherein polymeric resin is injected into lumber through means of an atmospheric pressure steeping method or the like and then polymerically cured in the inner part of lumber, and since the antiseptic agent has nothing therein at all, it is employed, as use, as an interior material of building materials.

CONSTITUTION: Polymeric resin liquid consisting of blending an emulsifying agent, polymerizing initiator, and pyroligneous acid into polymeric monomer or oligomer is impregnated into lumber, and ones obtained is polymerized by imperting heat &, light &, or other active energies, and thereby resin reinforced lumber is given mechanical strength as well as weatherability, thus enabling the using range of the lumber obtained to be extended to an exterior material of building materials.