Rule 35. - Contractor dealers.

Contractors and subcontractors engaged in the business of erecting, building or otherwise improving, altering and repairing real property for others, may also be engaged in the retail business of selling materials and supplies to other contractors, and consumers and users. If, at the time of purchase, the contractor is unable to segregate that portion of the materials and supplies he will sell at retail and that portion which he will use or consume in the fulfillment of his contracts, he should give a resale certificate to the seller of the materials and supplies. The contractor or subcontractor purchasing on a resale certificate must include in his gross sales, upon which the tax is to be computed, all proceeds from retail sales. In addition he will report and pay the tax on all materials he uses in the performance of his contracts, based on the cost price of such materials and supplies.

Where the contract with the customer is expressed in terms of a sale of certain materials at a stipulated price, plus a charge for installation, the contract shall be considered a taxable retail sale to the extent of the stipulated price of the materials.

Where the contract is expressed in terms of a sale of certain materials, coupled with an obligation to install them, for a lump sum charge, the entire charge shall be considered the selling price and shall be subject to tax.