A dwelling, accessory building and/or garage may be erected on any nonconforming lot in existence on the effective date of this article (except in an industrial or commercial district), provided that the present setback, side line, rear line and building area restrictions are met. In the event that these restrictions cannot be met, the Zoning Board of Appeals may vary the application of this article to permit the erection of a dwelling or garage on said lots after giving consideration, among other things, to the suitability of structural design on said lot, availability of additional land, adequacy of space for sewage disposal, parking and the fire hazard potential, if any.