This Architectural Drawing is AutoCAD 2d drawing of Backing rod of frame details in AutoCAD, dwg file. Backer rods are usually round, flexible lengths of foam that are used as a “backing” in joints or cracks to help control the amount of sealant/caulking used and create a back stop.Backer rods are used as a “backing” material to fill a void, joint, or crack in residential and commercial applications. The primary purpose of backer rods is to: Control the sealant thickness and amount needed to fill the joint. Force the sealant to the sidewalls to ensure contact and proper adhesion. For more details and information download the drawing file.