Building permits are requiredīuilding permits are required for, but not limited to, the following: Building permits are issued to ensure that proposed work complies with the structural, fire, and health requirements of the Ontario Building Code and other applicable provincial and municipal regulations. It is illegal to construct or demolish a building without first obtaining a permit. The Building Code Act requires that a building permit be obtained for the construction, demolition, or change of use of buildings. Permits and applications Building Permits