Short walls under 4 feet in height don’t require bracing, although if you want to include it as part of the overall structure you can do so based on your personal preference. As a general rule, retaining walls for planters, gardens, patios and other areas where there is no weight being put on the wall do not require bracing, but once you go over 4 feet in height or add weight to the equation you have to talk with a structural engineer.
Any type of wall that will have weight acting against it, either from above or along the sides, is known as a load-bearing wall and will require some form of bracing. The type of bracing will vary wildly depending on if you are working with brick, block, glass or some other form of masonry product that includes concrete as part of its internal workings. The only way to know for sure which type of bracing is best is to confer with a licensed professional.
One type of bracing is the internal kind, which is normally made up of rebar. Rebar is a steel-based material that comes in rod form and is placed both horizontally and vertically within a structure to help strengthen it to handle the weight of a load. The exact placement depends on the weight, the type of building material involved in the project and the surrounding building conditions, such as soil, exposure to salt water and excess moisture and weather.
Similar to how internal bracing has a number of different variables that can affect its performance and thus its bracing requirements, not all structures can rely on internal bracing alone. Some masonry projects need external bracing in the form of steel beams, support rods or paneling. They are usually braced at an angle and in extreme cases may even be hydraulic in nature, such as with skyscrapers that suffer wind buffeting.