In Martin v. Martin, 27 Va. App. 745, 753, 501 S.E.2d 450, 454 (1998), the Court applied the "Brandenburg formula," first approved in Hart v. Hart, 27 Va. App. 46, 497 S.E.2d 496 (1998), to calculate a husband's proper share of a marital home. See Martin, 27 Va. App. at 753, 501 S.E.2d at 454. The husband had used $ 26,634.22 of separate property to purchase a marital home worth $ 60,100. At the time of distribution, the home had a value of $ 110,000. The Court held that the husband's separate property interest in the home was $ 26,634.22, plus $ 22,113.88 of passive appreciation. Id. at 753 n.3 and n.4, 501 S.E.2d at 454 n.3 and n.4. Moreover, the Court held that the trial judge has a duty "to determine the extent to which a spouse's separate property interest in the home increased in value during the . . . marriage." Id. at 752, 501 S.E.2d at 453.