The Flush-Fin Application
For homeowners that have existing aluminum or steel frame windows and doors, a flush-fin installation method is required. Utilizing a flush-fin design, replacement windows and doors effectively bury your existing aluminum/steel frames. The extruded (vinyl or aluminum frames) and pultruded (fiberglass frames) design of flush-fin replacement windows and doors provides a self-trimming molding for the exterior of the window or door. In addition to providing a self-trimming molding, the flush-fin also provides a surface area to properly seal the new window or door to the old window or door frame. A.A.M.A has very specific guidelines for proper installation of a flush-fin replacement window and/or door.
The Block-Fit Application
For homeowners that have existing wood windows, the installation method that is most commonly used is called a block-fit application. Unlike a flush-fin (retro-fit) or a nail-fin (new construction) design, a block-fit window does not have any fin at all. Instead, the block-fit window or door is installed into and inside of the existing wood jamb. In most cases, the new block-fit window or door makes use of the existing stucco/brick mold to provide the exterior trim detail. However, if there is sever water damage, dry-rot, and/or termite damage to the existing wood frame or molding, these components may require a more comprehensive installation.
