[Gatto Nero]

Secondcurve,

I have no direct experience this this, and I'm certainly no lawyer, but in reading the rules regarding nonconforming structures I think I see some wiggle room.

483-B:11 Nonconforming Structures. –
I. Except as otherwise prohibited by law, nonconforming structures located within the protected shoreland may be repaired, renovated, or replaced in kind using modern technologies, provided the result is a functionally equivalent use. Such repair or replacement may alter the interior design or existing foundation, but shall result in no expansion of the existing footprint except as authorized by the department pursuant to paragraph II. An expansion that increases the sewerage load to an on-site septic system, or changes or expands the use of a septic system or converts a structure to condominiums or any other project identified under RSA 485-A:29-44 and rules adopted to implement it shall require approval by the department. Between the primary building line and the reference line, no alteration shall extend the structure closer to the public water, except that the addition of a deck or open porch is permitted up to a maximum of 12 feet towards the reference line for nonconforming structures erected prior to July 1, 1994.
II. When reviewing requests for the redevelopment of sites that contain nonconforming structures or any expansions of nonconforming structures the commissioner shall review proposals which are more nearly conforming than the existing structures, and may waive some of the standards specified in RSA 483-B:9, so long as there is at least the same degree of protection provided to the public waters. For the purposes of this section, a proposal that is "more nearly conforming'' means a proposal for significant changes to the location or size of existing structures that bring the structures into greater conformity, or a proposal for changes to other aspects of the property, including but not limited to stormwater management, wastewater treatment or traffic volume or flow, or both types of proposal which significantly improve wildlife habitat or resource protection.

It would seem to me, based on the items in bold, that since it's a covered deck it would already be part of the footprint, right? It is not adding any impervious area and there is the same degree of protection to the public waters. It's not clear cut but I would think there is a case to be made. Also, if you have a way of making the place more nearly conforming in some other way (new septic, maybe?) they might be more willing to work with you. One would hope anyway.