Inside mounts must have a jamb depth of at least 2", or 3" for flush mount. (Don't forget handle projection, if any).
Outside mounts will project 3" plus valance at top.
Inside mounts may be ordered without side frames with enough jamb depth.
Measure inside width in 3 places - top, middle, bottom.
Measure height in 3 places - left, middle, right.
For outside mount: Use larger measurements and add 4-1/4" to width and 2-3/4" to height. If mounting on top of existing trim, use largest measurements across from outside edge to outside edge of trim and floor to top of trim. If mounting to wall next to existing trim, add to the trim measurements, same as above.
For inside mounts: Use smallest actual opening measurements. Do not subtract from tight measurements. Factory will take proper deductions.
Locate divider rails by measuring from floor or sill (if window) up to the mid point of the desired location.
Definition: Mounting shutters recessed within the door opening is known as an "Inside Mount". When mounted outside the door opening on the trim (if any) or directly on the wall, this is an "Outside Mount".
Below are cross section views of typical inside and outside mount assemblies. Actual installation details may vary slightly from illustrations.
For illustrations of BiFold panel arrangements, click HERE.