Railings and stairs are the parts of a deck people touch every day, and the parts building inspectors look at most closely. They're also the easiest way to change how an older deck looks.
Railing options
Wood. Pressure-treated or cedar posts, rails, and balusters. The lowest cost and easy to repair. Needs stain along with the deck.
Composite or PVC. Sleeves go over treated posts, with matching top rails and balusters. Comes in the same colors as the boards. No staining.
Aluminum. Powder-coated aluminum posts and pickets, usually black, bronze, or white. Slim, strong, and doesn’t rust. A popular upgrade on older decks.
Cable. Stainless steel cables strung between sturdy posts. Opens up the view, which is why it’s common on lake and hillside houses. Cable needs very stiff end posts and periodic tightening.
Glass. Tempered glass panels in metal or wood frames. The clearest view and the highest cost. Glass needs cleaning, especially near trees.
| Railing | Rough installed cost per linear foot |
|---|---|
| Pressure-treated wood | $40–75 |
| Composite / PVC | $70–120 |
| Aluminum | $80–150 |
| Cable | $120–220 |
| Glass | $180–350 |
What the code requires
Connecticut’s building code is based on the International Residential Code. For decks the main railing rules are:
- When you need a railing: any deck surface more than 30 inches above the ground below it.
- Height: at least 36 inches from the deck surface to the top of the rail.
- Openings: a 4-inch ball shouldn’t pass through anywhere in the railing. That’s what keeps a small child from slipping through.
- Strength: the top rail must hold a 200-pound load pushed outward. That’s why posts need to be bolted and blocked, not just nailed.
Your town’s building official makes the final call, and some details vary. A builder who does decks regularly knows what local inspectors look for.
Stairs
Most deck stairs fail at the bottom, where the stringers sit on wet ground. Good stair building includes:
- A concrete pad or footings at the bottom so stringers don’t sit on soil.
- Even steps. Code limits risers to 7¾ inches and requires treads of at least 10 inches, with less than ⅜ inch of difference between steps. Uneven steps are what trip people.
- Stringers at 12 inches apart for composite treads, 16 inches for most wood.
- A graspable handrail 34 to 38 inches high on any stair with four or more risers.
- Stair railings on the open sides, with the same 4-inch rule as the deck (a slightly larger opening is allowed at the triangle under each tread).
Landings break up a long run of stairs on a high deck and give you a place to turn. They also make stairs easier to use with groceries or in snow.
Wider stairs are a good upgrade. Stairs 5 or 6 feet wide, or a wide box step along the side of a low deck, make the deck feel connected to the yard.
Lighting
Low-voltage LED lights in post caps, under the top rail, or in stair risers make stairs safer at night. They run off a small transformer plugged into an outdoor outlet. Adding them is easiest while railings and stairs are being built.
Common questions
Can I replace just my railing?
Yes. Railing replacement is common on decks with sound frames. It’s a good time to make sure the posts are properly bolted to the frame.
Does my low deck need a railing?
If the deck surface is 30 inches or less above the ground at every point, code doesn’t require one. Many people add one anyway, or build wide box steps around the edge instead.
Why does my railing wobble?
Usually because the posts were nailed or lagged to the outside of the rim board without blocking. Through-bolts and blocking, or a post-mount bracket, fix it. See deck repair.
How much does a new set of deck stairs cost?
A short run of three to five wood steps with railings is often $900 to $2,500. Composite, wider stairs, and landings cost more.
Tell us about your deck.
Size, what’s wrong with it now, or what you’d like to build. Photos help.