How to Build a Balcony

Measuring the lumber used for a wood balcony.
  • 168-216 hours
  • Advanced
  • 2,000-6,000
What You'll Need
Pressure treated lumber
Measuring tape
Circular saw
Carpenter square
Lag bolts
Joist hanger
Wood screws
Wood adhesive

Learning how to build a balcony for your home is a great way to add both style and class to your exterior. Balconies can give you a completely different perspective on the area you live in and provide great outdoor views for visitors as well. There are numerous considerations to keep in mind when building a balcony. The following information will make building your own balcony a simple DIY project.

Step 1 - Design Your Balcony

The first thing that you are going to want to do is to design the balcony using the desired materials and the desired dimensions. The best type of wood to use for any project that involves the outdoors is wood that has been pressure treated as it is capable of standing up against the elements and insects better than other types of lumber.

Make sure your design plans incorporate any local building codes regarding balcony construction. At the very least, these codes give you guidelines for floor joist spacing, hand rail height, and baluster spacing.

Step 2 - Purchase Materials

Now that you know what your basic plan is, visit your local hardware store so that you can purchase the necessary materials. We have mentioned most of the materials that you will need at the beginning of this article, but your materials may differ depending on the exact plans for your balcony design and construction.

Step 3 - Begin Installation

Begin by cutting your ledger and floor joists to the desired measurements depending on what your individual plan is for the construction of your custom balcony. Nail these pieces into place and make sure that you are using lag bolts to secure the ledger. Use six-inch lag bolts at a minimum for the best possible results.

Next, fit the joist hangers in order to secure the floor joist in its place. Again, check to see if there are any regulations for joist spacing in this case.

Step 4 - Install Subfloor

Now you are prepared to install your subfloor, which can be made from plywood. Make sure that the subfloor is both glued and properly screwed into the joists for it to be sturdy and secure.

Step 5 - Add Railing Support Posts

Once this is complete, you can fix the corner support posts which will be used for the hand rails. Cut pieces of 4x4 lumber to the prescribed height (about 36 to 42 inches above the balcony floor is standard) and anchor them to the subflooring. You may add extra support posts for the railing if your balcony is particularly large. This way, the railing lengths can be kept short to prevent them from sagging in the middle.

Step 5 - Attach Hand Rails

Use 2x2s for the tops of the hand rails so they are easy to grip, securing them to the support posts you've installed around your balcony. Your balusters can be cut into whatever design or width you would like, but they should be spaced no more than four inches apart when secured.

Step 6 - Establish Floor

With whichever lumber you decided on in the beginning, it is time to attach your real balcony flooring. In your initial plan, you should have laid out how you wanted the boards to be cut for your size, floor plan, and dimensions, so at this time, cut your flooring lumber to size and begin securing it to the sub flooring with wood screws and adhesive.

Step 7 - Finish Up

Now you can complete the finishing touches on your own personal balcony, including staining, sealing, or painting the hand rails and the rest of the balcony so that it matches your home properly.