Both are types of zoning relief. A Special Permit is required where the proposed use or development is identified by the Zoning By-Law as requiring one. Special permits will be outlined in the tables and text of the By-Law as available for certain uses or certain dimensional exceptions if the ZBA finds that the applicant meets specific criteria.
A variance is required if the proposed use or development is prohibited by the By-Law. The applicant must prove that there is uniqueness to their lot whereby a literal interpretation of the By-Law would cause a hardship warranting an exception from the Zoning By-Law. The application process for variances and special permits is the same. An application is located here.