((a)) The Secretary shall not insure under section 1713 or or under pursuant to any application for insurance filed subsequent to the effective date of this section, or under , or under subchapter VII pursuant to any application filed subsequent to sixty days after , or under section 1748b or 1748h–2 of this title, or under , a mortgage or investment which covers property on which there is or is to be located a dwelling or dwellings, or a housing project, the construction of which was or is to be commenced subsequent to such date, unless the principal contractor files a certificate or certificates (at such times, in course of construction or otherwise, as the Secretary may prescribe) certifying that the laborers and mechanics employed in the construction of the dwelling or dwellings or the housing project involved have been paid not less than the wages prevailing in the locality in which the work was performed for the corresponding classes of laborers and mechanics employed on construction of a similar character, as determined by the Secretary of Labor, in accordance with sections 3141–3144, 3146, and 3147 of title 40, prior to the beginning of construction and after the date of the filing of the application for insurance. The provisions of this section shall also apply to the insurance of any loan or mortgage under section 1715k or which covers property on which there is located a dwelling or dwellings designed principally for residential use for twelve or more families. The provisions of this section shall apply to the insurance under section 1715 of this title of any mortgage described in subsection (d)(3) or (d)(4) and (deeming the term “construction” as used in the first sentence of this subsection to mean rehabilitation) of any mortgage described in subsection (h)(1) or which covers property on which there is located a dwelling or dwellings designed principally for residential use for more than eight families; except that compliance with such provisions may be waived by the Secretary—

((1)) with respect to mortgages described in such subsection (d)(3) or (d)(4), in cases or classes of cases where laborers or mechanics (not otherwise employed at any time in the construction of the project) voluntarily donate their services without compensation for the purpose of lowering their housing costs in a cooperative housing project and the Secretary determines that any amounts saved thereby are fully credited to the cooperative undertaking the construction, and

((2)) with respect to mortgages described in such subsection (h)(1) or , in cases or classes of cases where prospective owners of such dwellings, voluntarily donate their services without compensation, or other persons (not otherwise employed at any time in the rehabilitation of the property) voluntarily donate their services without compensation, and the Secretary determines that any amounts saved thereby are fully credited to the nonprofit organization undertaking the rehabilitation.

((b)) The Secretary is authorized to make such rules and regulations as may be necessary to carry out the provisions of this section.

((c)) There is authorized to be appropriated for the remainder of the fiscal year ending , and for each fiscal year thereafter, a sum sufficient to meet all necessary expenses of the Department of Labor in making the determinations provided for in subsection (a).