Vertical blinds typically hang like draperies. These blinds are often used for large windows or sliding glass doors. All vertical blind vanes rotate and usually draw like draperies. You may request a two-way or one-way draw. For glass sliding doors a one-way draw works best. An outside mount is most common for this type of blind because they usually require a window opening depth of at least 4 ½”, and patio door handles protrude and would interfere with an inside mount. However, vertical blinds can be mounted inside the window frame, if your window has enough depth.
Measuring for vertical blinds with an outside mount requires you to measure the width of the window trim including the frame, then add at least 4” on each side for overlap and minimum light gap. When measuring for blinds, any kind, you must be extremely accurate to ensure the proper width, length and fit for your window.