(1) The structural design of foundation, masonry, timber, plain concrete, reinforced concrete, prestressed concrete and structural steel shall be in accordance with the provisions of the latest edition of the National Building Code of India and relevant Codes of practice of the Bureau of Indian Standards meant for plain and/or hill areas, as provided in rule 86:
Provided that for the municipal areas in hill areas, the structural design for all parts of the building shall be prepared taking into consideration the seismic factors in accordance with the relevant BIS Codes of Practice or Guidelines.
(2) Unless otherwise specifically provided for in the Act or these rules, all materials and workmanship shall be of good quality, conforming generally to the accepted standard of the Public Works Department of the Government of West Bengal or Indian standard specification as included in the Part V on Building Materials and Part VII on Constructional Practice and Safety of the latest edition of the National Building Code of India.