b'exterior temperatures, and can condense on the cold-er outer surfaces of the window and especially thealuminum capping. This condensate, if trapped, cancause mold, mildew and rotting within the cavity.Aninstallation that breathes allows evaporation of themoisture-laden air reducing the chance of this dam- Removeaging condensation. OldThere are other advantages to this method. OldWindowpulley holes, the space vacated by the parting stops, Shear off Installand other problems are covered by the F Channel. Blindstop F-ChannelThe insulation, often used in the cavity, now fills the on Sidesspace between the window frame and the F-Channel. and Header.The F-Channel, when installed, can be anchoredusing a sealer caulk, and (if necessary) large headroofing nails to hold it in place. The F-Channel on the sides of the opening should be notched to matchwith the legs of the header channel. If installed in anopening with a sloped sill, the bottoms of the sidechannels should be trimmed accordingly.The opening left after old aluminum fin-mountedwindows are removed can be similarly covered with F-Channels, effecting a better sealed finishedinstallation, and eliminating the need for appliedpieces to act as a blindstop. Cap Old Steel OpeningWindowin BrickOpeningFinished Installation using F-Channel.AFTERNew VinylWindow NOTCH FORInstalled BEST FITwithF-ChannelWindow Fitters Guide to Window Installation892020 AWDI, LLC Do not reproduce without permission'