A town on the Neuse
The Neuse River runs through Smithfield, and the National Weather Service’s gauge at the town has the record to show for it. Major flooding there begins at 20 feet. The river’s highest recorded crest was 29.09 feet on October 10, 2016, after Hurricane Matthew, with 27.4 feet in September 1996 and 26.72 feet in September 1999 behind it (National Weather Service, Neuse River at Smithfield). Hurricane Florence, in September 2018, crested lower, at 18.91 feet: moderate flooding, the stage at which, in the Weather Service’s own words, the Smithfield town park and the Neuse Riverwalk at the US 70 bridge are flooded. Anyone who has lived here through one of those does not need a web page to explain what water can do.
But flooding is the dramatic version of this problem, and it is not the version most Smithfield homeowners are dealing with. The far more common story is a crawl space that stays damp - not flooded, just never properly dry - in a house that is nowhere near the river and has never had a flood claim in its life.
That distinction is the point of this page, because the two situations need different responses.
The slower problem
Sustained rain saturates soil. Saturated soil cannot absorb more, so additional water travels laterally at shallow depth until it finds somewhere to go. A crawl space floor sitting below the level of the surrounding yard is an extremely effective collection point.
This area is on the edge of the Coastal Plain, where soils are sandier than Piedmont clay. Sand drains faster, which genuinely does reduce standing water compared with the counties to the west. What it does not do is lower the water table. In low-lying ground the water table can be close enough to the surface that soil under a house stays moist year-round, releasing moisture upward into the crawl space with nothing visible ever appearing.
So a Smithfield crawl space can be damp for two reasons that look nothing alike: an event, or a condition. Working out which you have is the first thing a contractor should do.
Drying out after water
If water has been in the crawl space, the sequence matters and the clock matters.
Remove the water. Pumping out is the immediate step, and it is not the end of it.
Remove what has absorbed it. Wet fiberglass insulation holds moisture against the subfloor and is generally replaced rather than dried. Cardboard, stored belongings and any organic debris under the house come out.
Dry the space properly. Wood that stays wet is where mold establishes, and the window for preventing that is short. Where growth is already established on joists or subfloor, mold remediation is part of the work.
Then find out why. Drying a crawl space that will take water again in four months is a repeated expense. Waterproofing and drainage is what turns a recurring event into a handled one, and a sump is the last component of that system rather than the whole of it. The published figures show what crawl space drainage costs.
Older Smithfield houses
As the Johnston County seat, the town has a substantial stock of early- to mid-twentieth-century housing in the neighborhoods around downtown, much of it on original crawl space foundations. Those were built long before a ground cover was expected, so bare earth underneath is the normal starting condition rather than evidence of neglect.
The Census Bureau’s figures bear that out. Smithfield has the oldest housing of the twenty communities this site covers: a median year built of 1973 across roughly 5,600 homes, about a quarter of them built before 1960, and only about one in seven built in 2000 or later (American Community Survey, 2020-2024). The North Smithfield Historic District, listed on the National Register in 2000, covers houses built from about 1850 to 1950 (North Smithfield nomination).
What matters in these houses is what decades of that have done to the wood. Where joist ends have softened at their bearings, where a girder has sagged, or where subfloor has gone spongy underfoot, the answer is structural repair before anything else. Where the framing is sound - and old-growth lumber often is - moisture control can proceed straightforwardly.
Who permits the work, and the rules it is checked against
A building permit in Smithfield comes from the county: the town contracts with Johnston County Building Inspections for building permits and construction inspections (Town of Smithfield). Closing a crawl space needs one whatever it costs. Johnston County publishes its own copy of the closed crawl space rules its inspectors work from (Johnston County), which makes the standard easy to read before comparing quotes. Three of those requirements come up in most of them: foundation wall vents are prohibited in a closed crawl space; the ground cover is at least 6-mil polyethylene with 12-inch laps, over a floor graded to one or more low spots with a drain or sump pump at each; and where a dehumidifier is the drying method, it is permanently installed, rated at least 15 pints a day, and drained to daylight or an interior condensate pump.
Vapor barriers in sandy soil
This comes up often enough here to deserve its own note. Homeowners with fast-draining soil reasonably conclude that moisture is not their issue, because water never stands.
Vapor transmission out of bare soil is independent of drainage speed. A ground vapor barrier addresses that mechanism specifically, and where summer humidity through open vents is also driving condensation, a sealed encapsulation with a dehumidifier handles both sources together. For what the state actually requires underfoot, and what is simply common practice, see the North Carolina code requirements.
Whether you are drying out after an event or dealing with a crawl space that has simply never been dry, an inspection will tell you which one you have. Request a visit.
Also covered: Clayton and Zebulon.
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