The commission shall, if necessary, be authorized to employ the services of an architect or engineer, or both, to supervise the drawing of maps, plans and specifications for such grounds, building and its fixtures, and the construction thereof. No payments for such construction work shall be approved by the commission except upon the certification of the architect or engineer having the particular supervision thereof, or the architect or engineer of the municipality where no special architect or engineer has been employed for that purpose, that the work, construction, development, materials or fixtures are in conformity with the ordinance and any contract entered into thereunder by the commission.