Joist hangers are used in construction and designed to anchor wooden beams. Primarily in roofs, decking, floors and ceilings for the purpose of creating a strong, long lasting support. When installed correctly a Joist Hanger will preserve the wood joists to which they are attached, as over time the wood will naturally twist and move. A joist hanger will ensure the wood beams keep a true fitting, ensuring long term strength and rigidity.