W. Va. Code § 38-2-28

Proof of the sale to any owner, contractor or subcontractor of any materials, machinery or other equipment for use in the performance of any contract mentioned in this article, and of the delivery of such materials, machinery or other equipment to such contractor or subcontractor, shall be prima facie proof of the use of such materials, machinery or equipment in the erection and construction of such building or other structure and of the improvements appurtenant thereto, and upon the proving of such facts, the burden of showing that such materials, machinery and equipment were not used in such building or other structure or improvement appurtenant thereto shall be upon the owner or other person disputing such use thereof.