Garage and workshop additions on the North Carolina coast

Tell us what goes inside, and where on the lot you picture it. From the address alone, we can look up your town's limits and the wind speed there.

Three kinds of garage job

What you decide

• Attached to the house, or standing apart
• How many bays, and the door's width and height
• Windows in the garage door, or none
• A workbench wall, or a whole shop
• Power for tools, lights and the opener
• Heating and cooling, or none
• A storage loft overhead
• A door into the house

Each choice sets off others. A tall door for a boat means taller walls, which run into the town's height cap. A door into the house brings the door rules and carbon monoxide alarms. Heating and cooling bring insulation and a system of their own.

How the work runs

Design and permits come first, through our six steps. Then the garage goes up in this order.

Where it joins the house

An attached garage ties into a wall of the house. Damage in that wall that only shows once the work opens it is carried as an allowance in the price.

A garage on its own is a whole job.

A garage or workshop by itself is a job we take on. It gets the same lot check, wind rating and permit path as one built along with a remodel. Each decision goes into your private online workspace, with the reason behind it.

A place to live is an ADU.

A garage or workshop with no one living in it is a renovation addition. Add a bedroom or a kitchen, and it becomes living space with rules of its own. A garage apartment puts a home above the garage. A garage conversion turns the garage you have into rooms, and a detached ADU stands on its own. A bonus room for your own household, over an attached garage, is a second-story addition.

Converting your old garage into rooms? The new garage that takes its place is a garage addition like any other.

Wrightsville Beach

A detached garage up to 10 by 20 feet and 14 feet tall. It sits 15 feet from every lot line, behind the rear building line (Sec. 155.6.5, R-1 and R-2).

Oak Island

A detached garage meets the house's setbacks, as if it were attached. Up to 20 feet tall, or the house's height if lower. Accessory buildings together cover at most 10 percent of the lot (UDO 2.12 and 7.2).

St. James

Detached accessory buildings together reach at most 30 percent of the house's floor area. In R-20, each stands under half the house's height and 20 feet from side and rear lines (Sec. 2.7.5 and 7.4).

Southport

Two accessory buildings per lot, covering at most half the rear yard, up to 30 feet tall. One of 530 square feet or less can sit 5 feet from a side or rear line (UDO 3.6.A).

Carolina Beach

One accessory building per lot, up to 15 feet tall and a quarter of the house's lot coverage. It keeps the house's front and side setbacks, and stays 5 feet off the rear line (UDO 3.6).

Wilmington

Two accessory buildings at most, beside or behind the house, 5 feet from side and rear lines and no taller than the house. Together they stay within the house's floor area (LDC Sec. 18-199). Lots in legacy districts, such as R-20, keep the older rules.

Ocean Isle Beach

On the island, outbuildings and workshops stay inside the house's footprint, decks and porches counted (Sec. 66-281(r)).

Most towns keep a detached garage out of the front yard, beside or behind the house. The distance to the side and rear lines varies. It is 5 feet in Surf City and Wilmington, and in Southport for a garage of 530 square feet or less. Carolina Beach allows 5 feet at the rear and holds it to the house's side setbacks. Leland asks for 10 feet, or 5 on a home lot behind a 6-foot fence. Pender County asks for 10 feet, and Wrightsville Beach 15. In Oak Island and Caswell Beach, a detached garage meets the house's own setbacks. How close to the side line can yours go? On a narrow lot, that one number can decide between attached and detached.

An attached garage follows the house.

Joined to the house, a garage counts as part of it, so the house's own setbacks apply. A garage linked to the house by a covered walkway is a separate building under the code's bracing rules. How it counts for zoning is your town's call.

Many towns keep it no taller than the house.

Oak Island stops a detached garage at 20 feet, or the house's height if that is lower. Leland stops it at 15 feet or the house's height, whichever is less, and some of its districts allow 20 feet with a wider setback. Shallotte, Surf City and Wilmington hold it to the house's height. In St. James's R-20 district, it stays under half the house's height. Planning a storage loft, or a tall door for a boat? Start with the height limit.

The size cap follows the house or the lot.

Some towns measure the cap against the house. St. James counts its floor area, and Carolina Beach and Leland its footprint, which their codes call lot coverage. Others measure the lot. Oak Island allows 10 percent of it, and Surf City 10 percent or 1,200 square feet, whichever is greater. Wrightsville Beach sizes the detached garage itself.

The garage roof also counts toward how much of the lot can be built on, along with the driveway. Oak Island and Boiling Spring Lakes both count it that way.

Lots near the water add rules of their own.

On a lot along the sound, a creek or the ocean, the state's coastal rules can add a CAMA permit. Along a sound or creek shoreline, new building inside the state's shoreline area sits at least 30 feet back from normal high water. The local permit officer or the Division of Coastal Management decides what your garage needs.

In a mapped flood zone, a garage floor below the flood height is kept to parking, building access and storage. Most towns also keep a detached garage there unheated, with no one working in it. One over 150 square feet is raised to the flood height or floodproofed. FEMA treats a workshop as a full building, so it meets the flood rules for one.

A garage under a raised house

Is your house raised on pilings or a tall foundation? We can close in the ground floor below it as a garage, where your town's rules allow it. Below the flood height, the same limit holds: parking, building access and storage. The walls let floodwater through, with flood openings and, where the code calls for them, walls built to break away. Your town may add rules of its own.

Your community may review it too.

Inside the gates at St. James, the property owners' association reviews plans before the town's permits. In Southport's local historic district, a new garage needs a certificate of appropriateness before the building permit.

Code in force

2018 North Carolina Residential Code. An accessory building over 12 feet in any direction meets it (Section R101.2.1).

Building permit

Required at any cost: a garage adds load-bearing walls and wiring (General Statute 160D-1110). The zoning check comes first.

Design wind speed

130 to 150 mph. Brunswick and New Hanover: 140 west of US 17, 150 east. Pender: 130, except Topsail Township, at 140 west of the Intracoastal Waterway and 150 east (Table R301.2(4)).

Tie-down

Anchorage runs unbroken from the roof to the foundation. At 140 and 150 mph, the walls sit on continuous concrete footings (Sections R4503.1 and R4508.1).

Garage door

Tested for wind pressure, and rated from its own table by wind speed and roof height (Section R609.4; Table R4502(b)).

Energy code

None for a garage on the same lot as a house, by state law (Section N1101.1).

Every garage is permit work.

New walls that carry a roof take a building permit, whatever the job costs, and new wiring takes its own electrical permit. The residential code reaches any outbuilding more than 12 feet long, wide or tall. A garage is bigger than that, so the whole code applies, from the footings to the roof.

The walls are tied down from the roof to the foundation.

Wind tries to lift a roof off and slide a building off its base. So the state's high-wind rules tie each part of the garage to the next. Across Brunswick and New Hanover Counties, and in Pender's Topsail Township, a garage that is not on pilings stands on continuous concrete footings. The anchorage runs unbroken from the roof down to those footings. In the rest of Pender, the roof ties run down to the foundation too. The walls are braced and sheathed for the wind as well.

Built to the physics of the coast shows how wind works on a building, from the walls it pushes to the roof edges it pulls.

Your garage door gets a rating of its own.

The garage door is the biggest opening in the building. If it gives way in a storm, the wind gets inside. Its rating comes from the code's own garage door table, set by the wind speed and the height of the roof. The door has to meet a standard written for garage doors (ANSI/DASMA 108). On the barrier islands, east of the Intracoastal Waterway, any glass in it needs impact protection too. Impact windows and doors explains both ratings.

Do you want windows in the garage door? On the islands, that choice brings the impact rule with it.

The wall you share with the house.

An attached garage gets half-inch gypsum board on its side of the wall it shares with the house. A room above the garage calls for thicker, fire-rated board on the ceiling below it. A door into the house is solid wood or steel at least 1 3/8 inches thick, or a 20-minute fire-rated door. No door may open from the garage into a bedroom.

Ducts in the garage are sheet steel or another approved material, with no openings into it. The house's heating and cooling system never takes air from the garage or sends air into it. A garage that opens into the house also brings carbon monoxide alarms, placed as in a new house.

The floor slopes to the door.

The garage floor is concrete or another surface that can't burn. Where cars park, it slopes toward the door or a drain, so water and spills run out.

Building on a slab you already have

Enclosing a carport, or building on a slab you already have, is a job we take on once we check what's under it. The slab edge carries the new walls as it stands, or it needs work below first. What only shows once the work starts is carried as an allowance in the price.

The mower makes it a garage.

Under the State Fire Marshal's reading, what a space holds decides whether it is a garage. Keep a car, a riding mower, a golf cart or a boat in the shop, and the code treats it as one. Attached to the house, it then takes the garage's rules for the shared wall and the door.

Power for the tools.

A workshop's wiring, from one new circuit to a panel of its own, is permit work, and it is inspected. We plan the circuits around the tools you run, the bench lights and the door opener.

Heating and cooling change the plan.

We build workshops that are heated and cooled, with a vehicle bay or none, and plain ones too. State law leaves garages out of the energy code. A shop you heat and cool still needs insulation and air sealing to stay comfortable and dry. Airtightness explains why the sealing matters.

The house's own system can't serve an attached garage, so a heated garage gets a system of its own. Under the slab, the code lets a garage or an unheated outbuilding skip the vapor retarder. A shop you will heat and cool falls outside that exception, so its slab gets one.

Will you heat and cool the shop, now or later? The slab and the walls are the time to plan for it.