What it means to live somewhere with no rodent off-season
Most rodent advice is built around a single autumn migration and a winter of confinement. South Carolina does not work that way, and planning as though it does is why so many households here treat the same problem repeatedly. With median winter lows around 36F, the outdoor population never collapses. There is no month when the animals around your building die back, no natural reset, and no window where doing nothing is safe. What you get instead is continuous low-level pressure, punctuated by small increases when heavy rain floods burrows or when a food source outside disappears. That changes three things. First, timing: exclusion is worth doing whenever you can arrange it rather than rushing before a cold snap. Second, expectations: a plan that removes animals without closing openings will visibly fail here, usually within a few months, because the supply outside is undiminished. Third, maintenance: vegetation grows back fast in this climate, so a canopy cut back from the roof one year needs checking the next. The upside is that the work is not urgent in the way it is up north. You have time to get an inspection, compare two written scopes, and have the sealing done properly rather than in a hurry.
Raised houses, crawl spaces and 50 inches of rain
A large share of South Carolina housing sits above the ground rather than on it, on piers or over a vented crawl space, and that space is where most ground-level rodent activity begins. The air under a raised house stays humid nearly year round in a climate delivering about 50 inches of rain, and the wood above it responds accordingly. Sill plates and joist ends soften. Vapor barriers tear and hold standing water underneath. Insulation between the joists sags, absorbs moisture and becomes ideal nesting material. Anything living down there has shelter, water and bedding without ever stepping into daylight. The entry points follow a pattern worth memorising. Foundation vent screens rust through or get bent open at a corner. The crawl access door warps and stops seating flat. Every plumbing, wiring and duct penetration through the subfloor was cut oversized, and those holes are the route from under the house into the wall cavities and up into the kitchen. Work the space with a bright light held low so gaps show as bright lines. Screen the vents with quarter-inch galvanized cloth fastened at the edges, pack the penetrations with copper mesh, then fix whatever is keeping the ground wet.
What is feeding the population outside your walls
Sealing a building stops animals getting in. Removing the food decides how many are out there trying, and in this climate the food supply runs all year. Fruit and nut trees are the big one. Figs, pecans, citrus and ornamental fruit drop steadily, and windfall left on the ground under a tree feeds a rodent population for weeks. Picking it up is unglamorous and effective. Pet food is second. A bowl left out overnight on a porch is a reliable, high-value meal, and it also brings animals close enough to the building to start testing it for openings. Feed indoors, or take bowls up before dark. Birdseed is third, and spilled seed under a feeder is often the single most concentrated source on a property. Then rubbish. Bins sitting on soil with loose lids let Norway rats feed and burrow directly underneath, and on small lots one badly managed bin area supports animals for several houses around it. Finally cover. Dense ground plantings, ivy and unmanaged shrubs against a foundation let animals move without crossing open ground, and in a state that grows vegetation this fast, cover regrows faster than anything else on the list.
Rats overhead: what to do in the first week
If the noise is above a ceiling in a South Carolina house, treat it as a roof rat problem until you have evidence otherwise, and work through a set order. First, confirm the timing. Note when the movement starts and stops for two nights. After dusk and into the small hours points to rats; daytime activity points to squirrels and a different set of rules. Second, get into the attic with a light and look for the route rather than the animal. Droppings concentrate along travel lines, and a polished grease mark on a rafter or a top plate marks a path in daily use. Third, set traps on those lines, not in open spaces, and use several. Check them daily. Fourth, go outside and look up. Walk the perimeter and find where a limb, fence, downspout or vine touches the roof, then look at soffit returns, gable vents and roof plane junctions for chewed screen or lifted trim. Fifth, cut the access routes back. That step alone changes the traffic within days. Only after that does sealing make sense, because sealing while animals are still inside traps them in the attic and leaves you with a worse problem than you started with.
A three-week plan if you just found droppings
Week one is diagnosis and containment. Identify what you have from the droppings: rice-grain with pointed ends means mice, larger and blunt means rats. Put all dry food into glass or metal, clean thoroughly using the wet-and-wipe method rather than a broom, and set traps against walls where the evidence is. Write down where you find droppings each day, because the pattern is your map. Week two is the search. Walk the outside of the house slowly, low and high. Check foundation vents, the crawl access, the sill line, every pipe and cable entry, both garage door corners, the soffits and gable vents. Note every opening, including the ones you are not sure about. Inside, check under sinks, behind the range and around the water heater. Week three is decision time. If the catch count is falling toward zero and you found two or three obvious openings, close them with metal and finish the job yourself. If catches keep coming, if the droppings appear in new rooms, or if the openings are on a roofline you cannot safely reach, this is the point to get an inspection and a written scope. Either way, keep a few traps set for a fortnight after the last catch to confirm nothing new is arriving.