An assembly is a cost item that may include the labor, material, and equipment needed to construct a project component. This can include walls, floors, roofs, and other major structural components.

Assemblies are typically broken down into subassemblies to help provide more granular detail regarding the project components. In order for an estimator to properly analyze cost estimates and create accurate bids and takeoffs, they must have a thorough understanding of all assemblies related to the project. Assemblies typically factor in labor costs including material handling and setup time as well as any additional tools or equipment that may be necessary.

Additional items in assemblies may also include any permits or licenses required for certain project components as well as any product warranty requirements and liabilities associated with the assembly installation process.