I am thinking about putting in addition on my house, and I am told I may need a variance. What is that and how do I go about getting one?

The zoning bylaws in the city, generally speaking, cover restrictions on dimensions of buildings on a lot i.e., how far a house has to be away from the front lot line, the side lot lines and rear lot lines and how high the building can be built. The zoning bylaws also cover uses such as single-family districts, multifamily districts, commercial districts manufacturing districts and the like. When zoning first came into existence the objective was fairly simple. Keep the houses in one end of town and the businesses in the other. Like everything else these days nothing is simple about land use. As a result of that there are multi-use provisions to zoning bylaws and also there are overlay districts which  create confusion but also flexibility. Add to that that many properties are “grandfathered” which means that when they were built the property was legal but under current zoning bylaws the property would not comply. The variance is a request by an owner to the Zoning Board of Appeals to “vary” the bylaw as it applies to a particular property because given that property and its location within the zoning district, the intended use to be made of the property will not cause a detriment to what the zoning bylaw was intended to do. In order to get a variance you have to apply to the Inspectional Services Department for a permit which will then be denied because it does not comply with the zoning bylaw. You then apply to the Zoning Board of Appeals and you are given a hearing date. At the hearing you will be able to present evidence as to why you believe the Board can give the variance and the reasons it will not be detrimental to the neighborhood. If you hope to win at the Zoning Board of Appeals is very important to speak to your neighbors and other representatives of that neighborhood to enlist their support. If you don't get their support it is very unlikely that you will get the variance.