Deck building and replacement

Tell us how big a deck you picture and how high it sits. From the address alone, we can look up your town's deck rules and any coastal line on the lot.

Four kinds of deck job

The choices are yours.

• The size, the shape and how high the deck sits
• Joined to the house, or freestanding
• Wood or composite boards
• The style of the rails
• Where the stairs land
• Hot-dip galvanized hardware, or a stainless steel upgrade
• Lights or outlets, wired under an electrical permit
• A hot tub, on a frame and footings designed for it

Some choices bring rules with them. A deck floor more than 30 inches up gets a guard rail. A taller deck gets bracing. A hot tub calls for a frame and footings designed for its full weight. Your choices, and the reason for each, go into your private online workspace.

How a new deck goes up

A new deck is designed and permitted first, by our six steps. Then it goes up in this order.

Damage under old boards is priced as an allowance.

Pulling up old boards, or taking an old deck off the house, can uncover rot in the frame or the wall behind it. Damage that only shows then is carried as an allowance in the price. Where the house wall itself needs work, siding and envelope replacement covers it.

Add a roof, and it becomes a porch.

A deck stays open to the sky. Put a roof over it, and it becomes a covered porch, with a roof tied down for the wind. Close it in with glass, and it becomes a sunroom. Thinking of a roof later? Say so at the start, since a roofed deck takes its beams and joists from other tables.

Deck rules

North Carolina's own, written into the state's residential code. New deck work meets the rules for a new structure (Section R102.7.1).

Footings

One under each post, sized by the deck area that post carries, at least 12 inches below grade.

Posts

A 4x4 up to 8 feet tall, a 6x6 up to 20 feet. A deck with taller posts is designed by a registered design professional.

At the house

A treated band or corrosion-resistant flashing along the joint. Aluminum flashing is barred. The bolts follow a table for the wall, with a separate table for brick veneer.

Bracing

Needed once a deck joined to the house stands 4 feet up, or a freestanding deck more than 30 inches up.

Hardware

Fasteners in treated wood: hot-dip galvanized steel, stainless steel, silicon bronze or copper (Section R317.3.1).

Rails

Required more than 30 inches above the grade below: at least 36 inches tall, with no gap a 4-inch ball can pass (Section R312.1).

Boards

No. 2 treated Southern pine or an equal. Composite boards meet ASTM D7032 (Section R317.4).

The footings carry it.

Each post stands on a footing sized for its share of the deck. The more deck a post carries, the bigger its footing, and every footing sits at least 12 inches below grade. How a footing is sized walks through the same idea under a house.

A taller deck takes thicker posts. Past 20 feet from footing to beam, a registered design professional designs the deck. We also build decks on raised houses on pilings. A deck there must be engineered and permitted.

Bracing keeps it steady.

Wind and footsteps push a deck sideways. A low deck bolted to the house leans on the house to stay put. A taller deck, or a freestanding one more than 30 inches up, gets knee braces or cross braces. A freestanding deck can stand on posts set deeper in the ground instead.

The joint at the house stays dry.

Rain runs down the wall and can work in behind the ledger, the board that joins the deck to the house. The code calls it the deck band. Behind it sits the house's own untreated framing. So the code asks for a treated band or corrosion-resistant flashing along that joint, and it bars aluminum flashing.

Siding comes off where the ledger goes. The bolts follow a table set by how far the joists span. How a coastal wall drains and dries goes deeper on keeping water out of the frame.

Brick houses have their own bolt table.

Advice online often says a deck can't hang from brick veneer. That advice follows the national model code. North Carolina writes its own deck rules, with a table made for brick houses. The deck band is bolted tight against the brick with hot-dip galvanized bolts, each with a nut and washer. Is your house sided or brick? Each has its own bolt table.

Salt decides the hardware.

Salt air eats steel. FEMA's guidance notes that metal tucked under a deck, out of the rain, can corrode faster than metal in the open. Today's treated lumber is harder on metal too. So the code sets the hardware.

Anywhere in the state, fasteners in treated wood are hot-dip galvanized steel, stainless steel, silicon bronze or copper.

Stainless steel is the upgrade. FEMA's guidance says it resists salt air and usually outlasts most other materials. It also points to stainless where hardware will be hard to check later. A stainless hanger takes stainless nails, since mixed metals rust the weaker one faster. Coastal durability covers how we choose hardware for salt air.

Wood or composite is your call.

We build with both, and the pick is yours. Treated Southern pine is the code's base decking. Composite boards meet their own testing standard, which rates how each board performs. You choose for the look, the upkeep and how each one weathers in the sun. Inside the first 30 feet of a sound or creek, the coastal rule names wooden decks, as On the Water explains.

Rails and stairs follow the state's numbers.

A deck floor more than 30 inches above the ground gets a guard at least 36 inches tall. No gap in it may let a 4-inch ball through. Along stairs, the guard is at least 34 inches high. A run of four or more risers gets a handrail 34 to 38 inches high. Each riser is 8 1/4 inches at most, and each tread at least 9 inches deep. Rail posts and their bolts follow the same salt-air rule as the rest of the deck.

New boards, rails, pickets and treads

No building permit, on a job of $40,000 or less done to code (General Statute 160D-1110).

Joists, posts, beams or the ledger

A building permit at any cost, since each one carries load.

A new deck

A building permit at any cost.

Rebuilt parts

They meet the rules for a new structure. The rest of the house can stay as built (Section R102.7.1).

Town permits

Southport and Topsail Beach ask for a zoning permit for a deck. Calabash asks for a town permit for every deck.

New boards on a sound frame need no permit.

State law lets deck resurfacing go ahead without a building permit. That covers new decking, rails, pickets and stair treads on a sound frame, on a job of $40,000 or less done to code. Touch the joists, posts, beams or ledger, and the job needs a permit.

Brunswick County lists the same work on its page of jobs that need no permit. Town zoning, and the coastal rules near the water, can still apply.

Is the frame under your boards still sound? Soft joists, rusted hangers or a sagging beam turn new boards into a new frame.

A new frame takes a permit.

Joists, beams, posts, footings and the ledger carry the deck. Replacing any of them is permit work at any price. So is building a new deck.

Rebuilt parts meet today's code.

A rebuilt stair gets today's limits on riser height and tread depth. A new rail gets today's height and spacing. The rest of the house can stay as built.

Your town may ask for a zoning permit.

Southport asks for a zoning permit and a minor site plan for a deck. No licensed professional has to draw that plan. Topsail Beach also asks for a zoning permit for a deck. In Calabash, every deck needs a permit from the town's own inspections office. On an unbuildable oceanfront lot in Surf City, a deck waits for its zoning and building permits.

Your community may review it first.

An owners' association's approval is separate from the permit, and it can come first. The covenants recorded for your lot decide. In Southport's local historic district, exterior work needs a certificate of appropriateness before the building permit. In Wilmington's historic districts, rear-yard decks are among the minor works that staff can approve.

On a waterfront lot, the state's coastal rules draw their own line between repair and replacement. On the Water covers it.

A deck on the oceanfront

Seaward of the state's oceanfront setback, a raised deck of up to 500 square feet is allowed. An existing deck bigger than that can be replaced at its old size, with no enlargement. In every case, the deck stays landward of the vegetation line and leaves the frontal dune intact. The house must also stand and be usable without it.

On Oak Island, every new oceanside deck needs a CAMA minor permit.

Along a sound, creek or canal

Here the state's shoreline area reaches 75 feet in from normal high water. Beside Outstanding Resource Waters, it reaches 575 feet. In the first 30 feet, new building stays out, apart from a short list of exceptions. One is a deck that is slatted, wooden, raised and open to the sky. All such decks on the lot share a cap of 200 square feet.

Where does your lot meet the water: the ocean, a sound, a creek or a canal? Each has its own line.

Your town can draw a tighter line.

Repair and replacement count differently near the water.

Under the coastal rules, repairing a deck after weather or ordinary wear needs no CAMA permit. Replacing it counts as development and needs one. A same-size replacement in the same spot can be exempt. It has to sit more than 30 feet from the water and leave the frontal dune alone. Before repair work starts, the rules ask owners to consult the local CAMA representative.

A deck in a flood zone

In a V zone, an attached deck sits at or above the flood height, on supports that meet the house's foundation rules. A deck below that height stands apart from the house. In any mapped flood zone, an attached deck counts toward your town's 50 percent rule.