If your window extends higher than the lip of your window well you will need either an extension or a riser. Window well extensions are less expensive to install than window well risers because they use less material and take less labor time to fabricate. The both serve the purpose of closing the gap created by a high window and choosing over versus the other is generally a matter of homeowner preference. However, in a configuration where the window is a crank-out (casement style) only a riser will work properly to still allow the window to open out into the well.
Choosing between a vertical or horizontal extension depends on several factors and is usually left to the discretion of the installer. Generally, if your window extends less than 12 inches above the top edge of the window well than we will install a VERTICAL Cover Extension. This style of Cover Extension extends upward and covers the window on a VERTICAL plane.
If your window extends more than 12 inches above the top edge of the window well we will usually install a HORIZONTAL Cover Extension. This style of Cover Extension extends inward and covers the window on a HORIZONTAL plane. With our new thicker clear polycarbonate plastic we are moving more towards installing vertical extensions because no matter the height of the window, the clear material always allows a clear line of site outside the basement window.