If one employed to manage property for its owner is empowered to make such repairs only as are necessary to preserve and protect the property from ordinary wear and tear, he can not charge the owner with the expense of permanent improvements, or of rebuilding after a fire. Beckman v. Wilson, 61 Cal. 335; Planer v. Equitable L. A. Soc. (N. J. Ch. '97), 37 A. 668. See references under Sec. 307.