Wooden decks uniformly use joists as a support mechanism for the surface of the decks. Joists, which also appear commonly in floors, consist of a series of wooden boards that run between the structural beams of a surface. These boards attach perpendicularly to beams and help distribute and relieve weight stress placed on a deck. Joist hangers sit at the juncture of a joist and beam, attaching the two to one another to increase the strength of the structure and ensure a strong connection between these elements.
A joist ledger consists of an additional piece of wood added to the structure of a deck. This piece of wood performs the same basic task as a joist hanger, making the use of hangers unnecessary when using a ledger. Ledgers assume the same shape and dimensions as the structural beams used in deck construction. You attach a ledger to the bottom side of a beam so the two form an “L” shape. Joists sit atop the ledger, which acts as a shelf. Using a ledger gives you two points of attachment for your joist -- you affix them to the beam and ledger by driving bolts or screws through each into the joist.
Angle brackets and ties comprise two types of metal fasteners used to affix joists to beams. Though similar to joist hangers, they differ in a few ways. Angle brackets consist of two flat metal surfaces joined together in a “L” shape. One of these flat surfaces attaches to a beam, the other two a joist, forming a connection between the two. They differ from joist hangers in that hangers wrap around the bottom of a joist in a “U” shape, while brackets attach one on either side to a joist, with no support provided underneath.
Ties work exactly like brackets but assume different physical forms depending upon a specific purpose. Seismic ties, for instance, help protect decks from damage due to strong lateral motion, and can look like brackets or joist hangers, depending upon the manufacturer and type.
Always check building codes before building a deck or even making a decision on parts you need to make your deck. These codes contain sections for all types of projects, including deck construction. Your local deck building code should contain information about the accepted types of joist hanger alternatives in your area, such as ledgers, brackets and ties. A code can not only provide you with laws on what you can and can't use, but also give you ideas on the best alternatives to joists in your area.