9. Where the services of an architect or of an engineer are retained in view of the construction of a building, the architect or engineer must prepare plans and specifications for the building that are in conformity with the regulations under this Act.
He must, in addition, transmit to the owner,(1) before the beginning of work contemplated by the regulations for which he has prepared plans and specifications, a written statement certifying that these plans and specifications are in conformity with the regulations; and
(2) not later than thirty days after completion of the work, a written statement certifying that the work has been executed in conformity with the regulations, if he was responsible for supervising the work.