Custom home builder in Masonboro, North Carolina.

A mainland shoreline that looks across the sound at an island kept wild.

Masonboro is an unincorporated place, the name the southeastern shore of New Hanover County goes by between the Hewletts Creek edge of Wilmington and the county boat ramp at Trails End. Masonboro Sound Road and Masonboro Loop Road carry the community along the high ground above the marsh, and the two tidal creeks that cut inland from the sound, Hewletts Creek at the north end and Whiskey Creek toward the south, decide where the neighborhoods between them sit.

Across the sound and the Intracoastal Waterway lies Masonboro Island, which the state describes as the largest undisturbed barrier island on the southern North Carolina coast: 5,653 acres, 8.4 miles long between Masonboro Inlet and Carolina Beach Inlet, roughly 87 percent marsh and tidal flat, reachable only by boat. It has been the largest component of the North Carolina National Estuarine Research Reserve since 1991 and is a state Dedicated Nature Preserve. A sound-front lot here faces an unbuilt horizon. That changes what a view corridor is worth, and what the water-facing side of a house is asked to do.

The lots come in three broad kinds. There are older houses on the ridge along the sound road, a stretch of which forms the Masonboro Sound Historic District, listed on the National Register in 1992. There are marsh-front and creek-front parcels, where the marsh line matters as much as the setback line. And there are large wooded interior lots off the loop road, under live oak and pine on many of them, that predate much of the subdivision around them. A client buying in Masonboro may be looking at an older house on a big lot, or at raw, marsh-adjacent ground, and the two start from different questions.

One more thing shapes a Masonboro lot before design does: the city line. Wilmington's limits cut through the middle of this community. A parcel inside them answers to the city for zoning and a parcel outside answers to the county, whatever the mailing address says. The county's GIS parcel viewer settles which side a parcel is on, and it's the first thing we open on any Masonboro address.

The Wilmington city line can run through a Masonboro street.

For a parcel outside the city limits, the governing document is the New Hanover County Unified Development Ordinance, and it holds everything that shapes a house lot here: the residential districts and their dimensional tables, the accessory-use rules, the tree retention and conservation-resource standards, and the flood provisions. County Planning and Land Use administers it, with the Planning Director named as the deciding official on tree removal permits and zoning compliance, and the county's Building Safety department issues the building permit and runs the inspections.

For a parcel inside the limits, zoning review moves to the City of Wilmington under its Land Development Code and its own planning staff, though New Hanover County still issues the building permit itself and inspects the work on both sides of the line. The parcel record decides which side of the line a lot is on, and that answer goes into the site analysis before a drawing exists, which is one reason the process we follow opens with a site read and a regulatory read. Where the two codes differ on setback, height or trees, that difference becomes a design input early in the site analysis.

The water's edge brings a third authority. Masonboro Sound and its tidal creeks are estuarine waters under the Coastal Area Management Act, and the band of land along their shore is the Coastal Shorelines Area of Environmental Concern. Docks, piers and bulkheads are permitted by the NC Division of Coastal Management: routine, low-impact structures through a CAMA general permit, anything beyond a general permit's limits through the major permit process. New Hanover County is on the Division's list of local governments with their own CAMA Local Permit Officers, so a CAMA minor permit, the kind a house inside the shoreline area usually needs, is handled by the county.

Two parts of the UDO do most of the work on a wooded, sound-side lot. The tree retention standards apply to residential lots of record of an acre or more. The conservation-resource standards reach any parcel that holds a tenth of an acre or more of salt marsh, or sits within the marsh's setback. Article 9 then fixes the regulatory flood protection elevation at the base flood elevation plus two feet where one has been mapped. Planning and Land Use is the authority on what a specific parcel may build.

Jurisdiction

Outside the Wilmington city limits: New Hanover County. Inside: City of Wilmington. A parcel-level fact; check the county GIS parcel viewer.

Adopted code

New Hanover County Unified Development Ordinance for unincorporated parcels; City of Wilmington Land Development Code for parcels inside the city.

Permit review

County Planning and Land Use administers the UDO for unincorporated parcels; City of Wilmington handles zoning review inside the city limits. New Hanover County Building Safety issues the building permit and inspects on both sides of the line, including inside Wilmington.

CAMA

Coastal Shorelines Area of Environmental Concern along the sound and the creeks; docks, piers and bulkheads permitted by the NC Division of Coastal Management; CAMA minor permits through the county Local Permit Officer.

Flood maps and freeboard

FEMA Flood Insurance Rate Maps and the NC Flood Risk Information System; base flood elevation plus two feet of freeboard under UDO Section 9.5.

Ultimate design wind speed

150 mph east of US 17 (2018 NC Residential Code, Table R301.2(4)).

A sound-front lot here faces a long fetch across open marsh.

Masonboro lies east of US 17, which under the 2018 North Carolina Residential Code, Table R301.2(4), places it in the 150 mph ultimate design wind speed zone. What the table cannot say is the exposure. A house on the sound-front ridge with open marsh and water to windward meets a long, steady fetch; a house on an interior lot off the loop road sits behind trees and other roofs. The exposure category is read from the ground during the site analysis and carried into the structural design, and canopy that reads as shelter today can be gone in ten years, which is why the load path is engineered to stand without it.

Flood mapping follows the water. The site analysis reads the current FEMA Flood Insurance Rate Map and the NC Flood Risk Information System for the parcel: whether it falls within a VE, Coastal A or AE area, and the base flood elevation that applies. Where a BFE is mapped, the county UDO sets its regulatory flood protection elevation at that number plus two feet of freeboard, and the lowest floor is designed to it; where no BFE exists, the elevation is at least two feet above the highest adjacent grade. Two creek-front lots a few hundred feet apart can carry different elevations, so each is read from the map. The county's general code, in its flood chapter, adds the standards the maps imply: anchoring against flotation and lateral movement, flood-damage-resistant materials, and utilities and on-site waste systems designed against floodwater.

Hewletts Creek and Whiskey Creek are tidal. They rise and fall twice a day, and a sustained onshore wind or a named storm can push them well past their ordinary line without a drop of rain. The salt comes with that wind. The ocean is on the far side of Masonboro Island, but airborne chloride crosses a barrier island and a sound without difficulty, so fastener, connector and equipment selection here is the same durability decision it is on the beach. A 2013 news account of the sewer extension along the sound road noted the area's high groundwater table, and ground that wet makes drainage and foundation design a survey question on every lot.

The canopy is the other constant. On many of the older and larger lots, live oaks and pines hold the ground, and the UDO reads the biggest of them by trunk diameter: a live oak at 36 inches is a specimen tree, and where the tree standards apply it cannot be removed without a variance. Shade from that canopy lowers the solar load and slows drying. In a storm the same trees become a debris load the roof deck and the openings have to be detailed for. Both readings belong in the same site walk, and both are the kind of coastal condition argued through in why coastal homes need a different standard.

A marsh-front Masonboro lot can carry a 100-foot setback.

Before a Masonboro project is drawn, we walk the lot and deliver the formal site analysis as a written document, and it goes into the client's project workspace. On a dry inland parcel that document is mostly about sun, wind and drainage. Here it has a harder job: locating the line where buildable ground ends and regulated ground begins. That line is set by survey, by the county's conservation-resource standards and by the state's shoreline rule, and everything drawn afterward reasons against it.

The conservation-resource standards in UDO Section 5.7 apply to any parcel of record associated with a listed resource above a minimum size, and for salt marsh, brackish marsh and primary nursery areas that minimum is a tenth of an acre. A parcel counts as associated if the resource lies on it, even partly, or if the resource sits next door close enough that its setback reaches across the line. On a marsh-front lot that is a low bar to clear. The standards then call for conservation space and a setback from it: salt marsh on a residential lot draws the strictest of the table's four groups, a 100-foot conservation-space setback (Table 5.7.4, Group 1), plus a 35-foot vegetated buffer measured from the marsh edge under Section 5.7.5, in which little beyond a dock or a pier may be built. An uncovered deck with spaced boards may reach up to six feet into the setback, which is the kind of detail that decides where a porch goes. One exemption matters on a street of older lots: under Section 5.7.2.C, building one single-family detached house, a duplex, or up to two mobile homes on a parcel of record created before December 1, 1984 is exempt from this section entirely. The site analysis reads all of this from the UDO for the parcel in hand.

On a Masonboro parcel, that document has to answer:

• which code governs the parcel, county UDO or city Land Development Code, and the zoning district it sits in
• the conservation-resource boundary, the conservation-space setback and the vegetated buffer where salt marsh is present
• the base flood elevation and the regulatory flood protection elevation the lowest floor will be held to
• the landward edge of the Coastal Shorelines AEC, and the 30-foot development setback from normal high water that applies inside it
• whether the tree retention standards apply to the lot, and a survey of documented, significant and specimen trees if they do
• dock feasibility, given the shoreline in front of the lot and the permit path through the Division of Coastal Management
• drainage from the ridge to the creek, the water table, and where fill or grading would help or hurt
• sun through the canopy across the year, and which corridors toward the sound and the island are worth the glass

Under 15A NCAC 07H .0209, the Coastal Shorelines AEC reaches 75 feet landward of normal high water, and 575 feet where the shoreline is contiguous with waters classified Outstanding Resource Waters. Within that area, new development sits at least 30 feet landward of normal high water, with listed exceptions for water-dependent uses, pile-supported structures and certain small lots platted before mid-1999. Whether a given stretch of Masonboro Sound or its creeks carries the ORW classification is confirmed with the Division of Coastal Management, and the answer is recorded in the analysis beside the standard the design is held to.

Where the tree rules apply

Residential lots of record of one acre or more. A lot under an acre in a residential district, and a subdivision of five or fewer lots, are exempt (UDO Section 5.3.1).

Documented Trees

Dogwoods and American hollies at 4 in. trunk diameter; longleaf pine, pond and bald cypress and hardwoods at 8 in.; other conifers at 12 in. (UDO Table 5.3.4.A).

Significant Trees

Dogwoods, magnolias, native flowering trees and American hollies at 8 in.; longleaf pine, cypress and hardwoods at 18 in.; other conifers at 24 in.

Specimen Trees

Live oaks, pond cypress and bald cypress at 36 in. Removal barred without a variance; mitigation at twice the caliper inches removed (UDO Sections 5.3.5 and 5.3.7).

FORTIFIED Gold, built for shade and salt.

On the sound side of Masonboro, the canopy does almost as much to a house as the water does. Live oaks and pines shade long stretches of the ridge and the loop road, cutting the solar exposure that would otherwise help a wall dry out, while the tidal creeks and the marsh behind the lot keep the air moving across it heavy with moisture most of the year. A humid, shaded lot like this asks more of the envelope than open, sunny ground does: one built for Masonboro has to manage humidity it cannot count on the sun to remove.

Every home we design pursues FORTIFIED Gold, the top tier of the standard the Insurance Institute for Business and Home Safety verifies itself: a credentialed evaluator inspects the finished work before IBHS issues the designation, so the claim rests on that inspection. On a canopy lot the standard's roof and connection details do double duty, holding the deck down against the 150 mph wind this stretch of the sound carries and against the limbs a live oak drops in the same storm, so a mature tree overhead is a reason to build to that standard.

Shade slows drying more than it lowers a cooling load, and the enclosure here is detailed for that trade.

The airtightness number is sub-1.0 ACH50, and on a Masonboro lot it is doing two jobs at once: cutting the mechanical load the way it would on any house, and keeping humid outside air from ever reaching a cold surface inside a shaded wall where it could condense. It goes into the drawings as a design target and becomes a result only when the blower door on that house reports it, checked once the shell is closed and again before handover. The reasoning behind treating airtightness as a moisture question first is laid out in sub-1.0 ACH50 without stuffy interiors.

That trade shapes the assemblies themselves. Walls are detailed to shed incoming water and still release trapped moisture to at least one side, flashing at every window and door follows a sequence drawn before framing starts, and the roof deck is sealed so that water working past a lifted shingle in a storm still has nowhere to go. Equipment is sized to what the lot actually asks of it, canopy shade cutting the cooling load while the marsh keeps the moisture load high; a system oversized for that load short-cycles and leaves the air cool without drying it. Connectors, fasteners and equipment placement answer to salt in the air here too, a sound and two creeks removed from the ocean, and that is a specification decision made in design.

Both habits are set out in planning for moisture before it appears, and carried as fixed points in the airtightness standard and the moisture plan; the same specification discipline covers connectors and equipment under the durability requirements.

Masonboro's residential districts allow a detached ADU by right.

New homes, whole-house renovations and detached ADUs all answer to the same lot-by-lot logic in Masonboro: what the parcel record and the site analysis find on that specific piece of ground.

New construction on marsh-front, creek-front and wooded lots

New construction in Masonboro is a custom home built from the site analysis and the lines it drew. On a marsh-front or creek-front parcel, the flood elevation, the conservation-space setback and the shoreline rule shape the footprint before taste does. On a large wooded lot off the loop road the same wind and permit rules apply with more room to place the house, and the tree survey usually decides where. Lot area, width and setbacks come from the zoning district a specific parcel sits in. In the county's R-20 district, for example, a single-family lot needs 20,000 square feet and 90 feet of width, with a 30-foot front setback, a 25-foot rear setback, 15 feet on an interior side, and a 40-foot height limit that rises to 44 feet for a house on an open pier foundation. In R-15 the lot drops to 15,000 square feet and 80 feet wide, with a 25-foot front and a 20-foot rear. Which district applies is read from the county zoning map, and a city parcel reads from Wilmington's code instead. A marsh-front lot with a conservation-space setback often has less room to stage material than its acreage suggests, and a lot under specimen live oaks gets protection fencing before the first truck arrives.

Renovation along the sound road

Older houses on the ridge are candidates for whole-house renovation, particularly where the aim is to bring the roof, the openings and the wall assemblies of an existing house toward current wind and moisture performance while keeping what already sits well on the lot. A house within the Masonboro Sound Historic District carries a National Register listing, which recognizes the district and can open the door to preservation incentives. Design review comes from a local historic overlay: New Hanover County's UDO has none, and inside the Wilmington city line the city's Historic District Overlay applies where its zoning map draws one, which we check for the parcel before scope is set. Renovation is also where the wet ground shows itself. A crawlspace over a high water table, or an addition that would reach toward the marsh, is a moisture and setback question before it is a floor-plan question.

Conditions on a detached ADU

A detached accessory dwelling unit is permitted by right in every residential zoning district common in Masonboro, RA, R-20, R-15 and R-10 among them (UDO Table 4.4.3), so the real question is whether the conditions fit the lot: one ADU per lot, only alongside a single-family detached house, one off-street parking space, and, outside the Rural Agricultural district, a shared driveway with no second curb cut. Utilities are the other gate. A lot on Cape Fear Public Utility Authority water and sewer has to show adequate capacity for the added unit; a lot on well and septic answers to New Hanover County Environmental Health. A 2013 account of the CFPUA extension along Masonboro Sound Road named the Oyster Bay, Windchase and Whiskey Creek neighborhoods as the streets being connected, and pockets beyond that project may still be on septic. On a large wooded lot the ADU question is often a tree question too, since the second structure and its parking sit inside the same retention rules as the house.

Masonboro runs as a string of neighborhoods along the water.

At the north end, around Hewletts Creek, the community meets the city of Wilmington proper, and the Wrightsville Beach strand is a short drive away.

Working south, the community breaks roughly into:

• the Hewletts Creek edge, closest to Wilmington, where the city line is most likely to run through a street
• the Masonboro Sound Road ridge, with the older houses and the historic district above and marsh frontage below
• the Masonboro Loop Road interior, the larger wooded lots where the one-acre tree rules are most likely to apply
• Whiskey Creek and Trails End at the southern end, where the road turns inland toward Myrtle Grove

Trails End Road finishes at a New Hanover County park on the Intracoastal Waterway with a public boat ramp, which the state names, with the ramps at Wrightsville Beach and Carolina Beach, as one of the launch points for the Masonboro Island Reserve. It is county ground, which is itself a clue about jurisdiction at that end of the community. Past it the road bends toward the inland lots of Myrtle Grove, where the same county UDO applies to ground that sits further from the marsh.

South again, the sound gives way to the beach towns of Carolina Beach and Kure Beach, each with its own code and its own oceanfront exposure. A Masonboro project and a Carolina Beach project start from different ordinances and usually from different flood maps. What they share is the county, and the habit this practice brings to both: read the specific ground first, then draw.

Along the sound and up the creeks, construction is partner-executed under our direction, under North Carolina Residential Contractor License #109520. We're members of the Brunswick County Home Builders Association, reachable at 910-946-5512.