Abstract: An attaching device to secure soffits under the eaves of a roof and to cover their ends. The attaching device is made of two separate pieces with snap action interlocking means. A top piece is first secured to the eaves and, once the soffit is fitted and retained to the eaves, the bottom piece is interlocked with the top piece. The bottom piece has a plate part extending under the soffit. The same attaching device may be used to secure sidings on the outside walls of buildings.