ADU Construction in North Charleston, SC

North Charleston has a mixed housing stock: 50% detached houses, 7% attached or townhouse units and 27% in buildings of five or more units.¹ On a mixed stock, feasibility turns on the individual lot - detached houses on larger parcels are the usual candidates; attached homes rarely qualify. Building permits in North Charleston are normally issued by the city building department.^2,3 ADU plan review and permits go through the city building department; the contractor prepares the plan set and submits it.

Owners and renters are roughly balanced in North Charleston, with 50% of occupied homes owner-occupied (72% statewide).¹ Where most occupied homes are rented, ADU inquiries often come from owners of rental property; the feasibility review is the same. Most of North Charleston's housing is recent: only 32% of units predate 1980 (U.S. 50%) and 25% were built since 2010.¹ Newer subdivisions often carry HOA covenants that affect ADUs separately from zoning - check the CC&Rs before design spend.

North Charleston sits in IECC climate zone 3A (Hot-Humid).⁴ In a mixed climate zone, the energy code balances heating and cooling; insulation levels and window ratings are set by the zone. The median owner-occupied home in North Charleston is valued at $302,200 (ACS), above the South Carolina median of $259,000.¹ Home values above the state median tend to support fuller scopes; the written scope should still separate must-do from nice-to-have.

Cooling dominates the year: about 2,434 cooling degree days against 1,844 heating degree days (base 65°F).^5,6 In a cooling-led climate, attic ventilation, duct sealing and window solar gain are where the energy code concentrates.