Frameless windows offer you the opportunity to have a fully inside the opening blind. The normal 3 inch plus depth can accommodate almost every blind or shade on the market and allow it to be installed so that the room side is flush with the wall. Even the smaller sized vertical blinds can be installed as a true inside mount.
The process for measuring for an inside mount is exactly the same as any other inside mount except is critical that you measure the width at 3 or more places because frameless windows are usually finished with drywall, corner bead and joint compound they may be more untrue than a regular window opening. You always want to use the smallest of the width measurements as your opening width.
In all cases when measuring a frameless window do keep in mind that it is quite common for the opening to be more narrow on the front edge than it is near the glass. You must use the smallest width you measure if you want to install and use the blind hassle free.
Another consideration is the style of mounting bracket. Because the top surface of a drywall finished window opening is rarely flat and level the newer style concealed mounting brackets may not function as well as the older, traditional box brackets. Small, thin, stackable shims are shipped with the better brands that use concealed mounting brackets but they are a royal PITA to install. When using the box brackets, if your blind is not hanging level it is a simple matter to raise or usually lower one or the other to get it level.
It is rare but not unheard of for a blind to be mounted on the wall above a frameless window. It might be an extra small window unit, the customer may want a unobstructed view or in a few rare cases the windows might pivot into the room.
The measuring process is exactly the same as for an inside mount except you measure the opening and then add 2 inches to the width and 2 or more inches to length. I suggest 2 inches as a minimum because it is best to avoid drilling screws into the drywall corner bead if at possible. Sometimes it is not securely fastened and will pull away from the drywall while you are drilling or screwing.
The option of where the bottom of the blind stops is completely up to you. It should rest on an extended sill or drop below the opening if a sill is not present.
The suggested addition to the length is two inches for one inch blinds and 3 inches for a two inch blind. Of course you can always go higher if you want the blind to stack completely above the window.
This article or portions of this article were previously published in a significantly different form on two websites owned by the author, window-wizard.net and lexkyweb.com/windows. Those articles are no longer available at those locations. Copyright is renewed with this revised publication (01-31-2010).
