Windows | Door | Building Science / Envelope and More

What do I mean by “new construction” and “replacement” windows? The way most people understand the difference between the two is that new construction windows utilize a nailing flange (fin that protrudes out from the window frame surrounding entire perimeter of the window) to install the windows and replacement windows have NO nailing flange. This over simplification of these terms often leads to buying the wrong product and poor installations. However, for the sake of mutual understanding, when I use those terms assume that is what I mean.  Nailing Flange Around Window Frame 1st Myth: When replacing windows, always use "replacement windows" - aka no nailing flange. It’s actually almost the exact opposite. Replacement windows should almost always HAVE a flange for installation.  The only times I would deem it acceptable to replace a window withOUT a flange is twofold: 1. Your house was build pre 1945 and you have the old sash weight wood double hung windows. For installing ne...

  If you are familiar with construction, then you may know that measuring and ordering windows can be complicated. Whether they’re for a new construction house or a replacement project, it’s crucial to know the difference between “RO” sizing and “net” sizing.   Rough opening (RO) size is simply the framed opening size. Meaning after a window is framed by the framer, the width and height of the stud to stud measurement is the RO dimension. Net size (also called frame size or heel size) is the actual width and height of the window from outside edge to outside edge. New Construction: If you’re building a new house then windows are always part of the equation. Looking at blueprints it may seem obvious what the sizes are - especially if there is a window schedule. However, there can be some confusion about what the ACTUAL size of the windows will come.  The important thing to know is that all specs related to window sizing on house plans is always the RO size.   2850 = 2'...