A cantilevered balcony is a structure that extends outward away from a wall in a home or other building. It uses a cantilevered design — that is, the beams that hold up the balcony are secured only at one end, meaning the other end that extends outward from the structure is unsupported. While this design is aesthetically pleasing and not especially difficult to construct, it is not always the strongest option and can lead to problems as the structure ages. A cantilevered balcony must be maintained and inspected fairly regularly to ensure it is safe for use.
The clean look of a cantilevered balcony has made it a favorite among builders for centuries, but structurally, the design can lead to problems. If the balcony extends too far from the building with no additional support, the structure can become unstable, leading to a bouncing or bending feeling. This is especially true if common framing materials such as pine are used to construct the cantilevered balcony. Pine is a softwood, which means it will generally have more flex and be more susceptible to cracking and rot. This can lead to an unsafe balcony that can bend or break at any time. Many builders opt instead to use hardwoods or pressure-treated woods to build the cantilevered balcony.
If the balcony is built correctly, it can be a pleasant and aesthetically pleasing addition to the home. No supports are necessary at the outward end of the balcony, so the space beneath the balcony will be unimpeded by posts or other supports. The balcony itself can be a pleasant place to sit or stand, and additional features such as screening or a roof can add to the aesthetic and functional appeal. Even if the structure is built properly, regular inspection will be necessary to ensure the wood is not cracking, bending, or otherwise breaking under the weight of the structure.
Builders often adhere to certain guidelines that dictate how far a particular balcony can be cantilevered. If it is not cantilevered far enough, the space may not be functional. If it is cantilevered too far, the structure may become unstable or otherwise unsafe for use. The size of the joists will often dictate this distance, as will the joist materials and the spacing between each joist. Stronger materials and thicker, wider joists will allow for a longer cantilever.