W. Va. Code § 48-1-233
"Marital property" means:
(2) The amount of any increase in value in the separate property of either of the parties to a marriage, which increase results from:
(A) An expenditure of funds which are marital property, including an expenditure of such funds which reduces indebtedness against separate property, extinguishes liens, or otherwise increases the net value of separate property; or (B) work performed by either or both of the parties during the marriage.
The definition of "marital property" contained in this section has no application outside of the provisions of this article, and the common law as to the ownership of the respective property and earnings of a husband and wife, as altered by the provisions of article 29 of this chapter and other provisions of this code, are not abrogated by implication or otherwise, except as expressly provided for by the provisions of this article as such provisions are applied in actions brought under this article or for the enforcement of rights under this article.