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Footprints on the Shore: Waterfront Home Expansion Rules Update

Footprints on the Shore: Waterfront Home Expansion Rules Update

Footprints on the Shore: Waterfront Home Expansion Rules Update
John C. Bannon, Partner, Chair, Environmental & Land Use Practice Group

Are you lucky enough to own a waterfront home that is grandfathered from the normal minimum setback from the normal high water mark (typically 75’)? Have you been thinking of expanding your home someday, but haven’t gotten around to it? If so, be aware that your town’s ordinances limiting the permissible enlargement of such homes are about to change, if they have not changed already.

New rule may dramatically impact expansion opportunities

If you were expecting to take advantage of the rule that linked expansions to the existing floor area and volume of your home, you may be surprised that to find that your right to expand your house now depends on the total “footprint” of the structures on your lot. For owners of large, multi-story houses, this change may mean a dramatically smaller opportunity for expansion; for those who own small, single-story homes, the new rule may be a boon.

Under the old rule, any portion of a building that was legally nonconforming to the minimum shoreline setback could, over its remaining lifetime, be expanded by up to 30% of the floor area and/or cubic volume of the structure as it had existed on January 1, 1989. Thus, the more stories a home had, and the taller the ceilings in each story, the more the house could be expanded.

Under the new rule, in contrast, the maximum permissible enlargement of a nonconforming structure equals either:

  1. 30% of the area of the ground occupied by all nonconforming structures on the lot, or
  2. a specific allowance for expansion of that ground area.

The extent of the permissible expansion and the maximum height of the addition are also affected by

  1. the distance between the house and the water and
  2. the type of water body to which the home is adjacent.

A deeper dive on the new rule

It is beyond the scope of this article to explain all the potential applications of the new expansion rule. Hence, the following explanation of the new regulation applies only to a nonconforming structure that is located between 25’ and 75’ from the normal high water mark of the Atlantic Ocean:

Under the new rule, the “maximum-combined total footprint for all structures” present on the lot as of January 1, 1989 may be increased by 30% over the lifetime of the structures. A “footprint” is defined as “the entire area of ground covered by the structures on a lot, including, but not limited to cantilevered or similar extensions, as well as unenclosed structures, patios and decks.” A “structure,” in turn, means “anything temporarily or permanently located, built, constructed or erected for the support, shelter or enclosure of persons, animals, goods or property of any kind or anything constructed or erected on or in the ground.” The extreme breadth of the definition of a “structure” aids the property owner in this instance, because it (a) maximizes the types of improvements that can be considered when determining the total “footprint” of the lot as of January 1, 1989, and (b) allows any single structure on the lot to the expanded, not just by 30% of its own footprint, but – if there are other improvements on the property meeting the definition of a “structure” — by 30% of the ground area of all nonconforming structures on the lot.

The new rule allows the property owner to choose between the expansion allowance derived from computing 30% of the existing “footprint” and an absolute expansion limit of 1,000 sq. ft. – whichever is larger. As a practical matter, that means that property owners having a total of more than 3,333 sq. ft. of nonconforming “footprint” on their lot will opt for the 30% computation, while those having a lesser “combined total footprint” of nonconforming structures will be better off claiming the 1,000 sq. ft. expansion allowance.


Because it considers nothing but the area of ground occupied by nonconforming structures, the new rule will, relative to the old regulation, decrease the expansion opportunities for nonconforming structures that contain multiple floors and high ceilings. If you own such a grand dwelling, and your municipality has not yet adopted the new “footprint” rule, you had better apply immediately for a permit to build that expansion you’ve been putting off. If your home is modest, however, procrastination may have been wise, for the new footprint rule may create expansion opportunities that never existed before.