How to Build a Balcony: A Complete 6-Step Guide

Sip coffee and take in the sights perched on top of your handiwork

Ben Kissam
Written by Ben Kissam
Updated May 11, 2022
A balcony with many plants
Photo: Oscar Wong / Moment / Getty Images


Don't DIY if you don't know what you're doing.

Time to complete

72 hours

3+ days

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What you'll need:


  • Circular saw
  • Jigsaw
  • Post hole digger/auger
  • Power drill
  • Stud finder
  • Climber


  • 3-inch screws
  • Lag screws
  • Cement
  • Rebar
  • 4-by-4s or 6-by-6s (for posts)
  • 6-inch wide boards (for joists)
  • 12-inch deck lumber (for floor)
  • Caulk or flashing for ledger board
  • Corner brackets
  • Premade balcony railing

Imagine how relaxing it would be to sip a warm cup of coffee—or a frosty beer—from the comfort of your own two-story balcony. Guess what? It's totally possible if you're willing to put in the work.

However, building a balcony from scratch isn't a project for the casual weekend DIY warrior.  But with some thorough planning and careful work, you can realize the dream of building a balcony onto your home. Learn how to build a balcony in this step-by-step guide.

Prepping to Build a Balcony

Make Sure Building a Balcony DIY Is For You

Building a balcony is a challenging proposition involving lots of cutting, drilling, and setting. You will have to work from a ladder and drill directly into your home's rim joist—which, if damaged, could compromise the structural integrity of your home.

All this to say, make sure this is a project for you to tackle DIY. The average cost for a new balcony or deck is $7,630. You'll definitely spend more, but a local deck-building professional can ensure the job goes accordingly.

Treat this guide as a rough outline for your project. Each homeowner will need to check local codes and ordinances and consider their current yard when designing their build.

Get Building Permission (If Necessary)

Speaking of guidelines: Depending on your municipal building authority, you might need a permit to build a balcony or second-story deck on your home DIY. Failure to do so could result in the whole deck being removed, as well as substantial fines.

Do your research and call around to verify you have all the necessary permissions to build before starting. Expect to pay a permit fee of around $25 in many states.

Design Your Balcony

Seek out design inspiration and determine what type of balcony youl want to build. A standard two-story rectangular balcony is what we'll discuss in this guide, but modifying the design or adding things like a walk-up staircase may fit your space and goals. 

We'll also assume you have a window or home entry in mind for your balcony. Otherwise, you'll need to spend a few extra steps determining construction needs or how you'll install a walk-up staircase for an external second-floor balcony.

Purchase All Necessary Materials 

The easiest way to figure out how much wood you'll need is to determine the square footage of your balcony. Your joists and frame pieces will vary based on the dimensions you choose. It will also factor in when deciding how big your post holes will be.

A small balcony is usually 4 feet by 9 feet, which creates enough room for a small table and two people to sit. Slightly bigger would be a 5 feet by 10 feet or 5 feet by 12 feet balcony, which can fit a table and things like a balcony garden, if you're interested in that sort of thing.

Pressure-treated wood rated to last at least 15 years is a popular choice for outdoor balcony builds. Deck lumber, red cedar, and composite deck board are all popular options as well.

6 Steps to Build a Balcony

  1. Install Post Holes and Insert Cement

    Use an auger or post hole digger to create four post holes. Again, check local ordinances to determine how deep the holes need to be for a balcony or second-story deck. Each post hole should be three times the diameter of the piece of lumber.

    Place your 4-by-4 or 6-by-6 posts into the hole, then fill with cement to secure them. You'll likely need an extra set of hands for holding the beams still as one person pours cement and sets it. Read your quick-drying cement instructions and follow them carefully.

    If you're building an especially heavy or large deck, insert rebar into the top of each post hole.

  2. Drill Ledger Board Into the Rim Joist of Your Home

    The first step for building the balcony frame is to secure a ledger board to your rim joist. You'll need to remove siding from the home to get direct access. Use lag screws to drill the board into your foundation—approximately every 12 inches.

    The ledger should be as close to the home as possible. Assuming an entryway is above it, the board should be as fit and snug as possible underneath to prevent water seepage from rotting the wood over time. Install flashing or caulk when you're finished to prevent leaks.

  3. Build Your Balcony Frame

    To build the frame, attach 2-by-6s to the ledger board. The outside portion of your balcony should be double-framed for support. Use two boards cut to the same length on all three sides not touching the rim joist. Screw them in with two lag screws fitted to a corner bracket.

    If possible, position your double frame directly underneath a double stud in the wall. Use a stud finder to locate stud points and mark them with a pencil or pen.

    Lastly, attach your frames to the posts using lag screws and a corner bracket.

  4. Secure Your Joists

    Install the balcony joists or wood beams that'll form the base of the floor. Insert a 6-inch board every 12 inches, starting at the rim joist, then securing it to the opposite side of the frame.

  5. Install Deck Boards

    A man cuts deck boards
    Photo: Jean-philippe WALLET / iStock / Getty Images

    You can buy deck boards at home improvement stores for around $20 per piece. It's up to you whether you'd like to cut these into individual 12-inch pieces and layer or install them as one long beam across your hoists.

    Deck boards are usually 5 1/2 inches wide and 1 inch thick. You'll establish the board length needed after determining the size of the balcony. Use screws to fasten boards to your joists. Work slowly and use nails to reinforce if needed.

  6. Install Hand Railings

    For railings, you can either use lumber or buy a premade balcony railing kit from a home improvement store. The latter will cost between $60 and $100 for 6 feet of railing.

    Read the manufacturer’s directions on your kit. In either case, you'll likely need to drill holes every 3 to 6 inches—depending on railing gaps—into your doubled-up balcony frames. Drill starter holes, then fasten using screws or as described on the packaging.

Building a Balcony DIY vs. Hiring a Pro

Building a balcony is a substantial DIY project, so make sure you feel comfortable with the magnitude and scope of the project before starting. Carefully research your project, and plan how to safely (and legally) build one in your area.

A local deck builder with experience can be an invaluable asset for your build and also guarantees the job winds up looking exactly the way you want it to.

Need professional help with your project?
Get quotes from top-rated pros.