Home Additions on Hilton Head Island

A home addition on Hilton Head typically runs $550 to $750 per square foot. A 250 sq ft addition, for example, usually falls between $138K and $188K. That range covers design, selections, construction and the workmanship warranty under one fixed price, with no change orders once the build contract is signed. The exact number for your project depends on size, finishes and site conditions, which is why HHI starts with a feasibility check and a room-by-room cost range before anything is committed.

In many cases, yes. Adding a second story usually means adding new structure and footings, and in some cases a second story can be built on new structure inside the existing walls, which involves significant demolition below. Homes with adequate existing footings tend to be the best candidates. The main limit is architectural review board height rules. In a plantation community, you normally cannot exceed the existing roof height, so a low roofline can rule it out. HHI confirms what your home can support as part of the feasibility study, alongside the survey, setbacks, ARB approval and engineering review that come before anything is committed.

Often, yes, but it depends on how the attic was originally framed. The key factors are headroom, whether there is room to add a proper staircase, and whether the existing ceiling joists are strong enough to serve as floor joists, or can be reinforced to do so. Attics that were framed as bonus rooms tend to convert well, since much of that structural groundwork is already in place. If your attic doesn't check those boxes yet, it doesn't necessarily rule out a conversion. It just means more of the structural work has to happen first. A design conversation is the best way to find out what your attic can become.

Setbacks limit how close an addition can come to your property line, and most additions cannot cross that line unless the existing home already does, in which case a variance from the ARB is possible. Community rules add another layer: any outdoor or exterior work in a plantation, and some areas outside them, needs ARB approval before the Town will accept a permit application. HHI's design process checks both before anything is committed. The survey, setbacks, ARB approval, engineering and a feasibility check all happen up front, including a conceptual submission to the ARB, which typically responds in one week to one month depending on the plantation. That way you know what is possible before you commit to it.

The Town of Hilton Head Island does not permit accessory dwelling units. Its Land Management Ordinance has no ADU use category, and a unit with its own kitchen and bath counts as a separate dwelling. A second dwelling on one lot is only allowed where the lot's zoning density permits two homes, which is rare on the island, and most plantation covenants prohibit it regardless. If you need more room, an addition is the path that works: a guest suite, office or in-law space built without a second kitchen. HHI's design team can walk through what your lot and community allow before you commit to anything.