Measuring for Divider Rails and Split Tilt

By Coverly Shutters

Divider rails and split tilt are positioned the same way, so they share a guide. A divider rail is a horizontal rail across the panel that supports the louvers and stops them sagging. A split tilt divides the louvers into two independently operated sections, so you can close the lower half for privacy and leave the upper half open for light.

Divider rails

A divider rail is required once a shutter passes a certain height, and the height depends on the material:

  • Economy Polyresin: 1 divider rail required over 62" tall.
  • Hybrid Wood: 1 divider rail required over 72" tall.
  • Painted or Stained Wood: 1 divider rail required over 84" tall.
  • Any material: 2 divider rails required over 96" tall.

Below those heights a divider rail is optional. If your window has multiple panes, we recommend adding one anyway and lining it up with the window's own horizontal bar, so the shutter matches the window behind it.

The divider rail is 1/4" narrower than the louver size you choose. A 4" louver gives a 3 3/4" divider rail.

Split tilt

A split tilt shutter adds privacy without giving up daylight. One section of louvers can be closed while the other stays open, which is why it is a common choice for bathrooms and for ground floor rooms facing a street.

split tilt plantation shutters

Measuring the position

The same measurement places both. Measure from the bottom of the window up to the middle of the point you want the rail or the split.

For an inside mount

  • With no sill, measure from the bottom of the recess.
  • With a sill, measure from the top of the sill.

inside mount divider rail measurement

For an outside mount

  • With molding, measure from the edge of the molding.
  • With a sill, measure from the top of the sill.

For a second divider rail

Follow the same instruction, measuring up to the middle of the second rail.

measuring for two divider rails

One thing to expect

Divider rail and split tilt positions may be adjusted by up to 2" either way, so that the louvers fit evenly across the panel. If the exact position matters to you, say so in your order notes and we will work as close to it as the louver spacing allows.

Not sure where to put it? Send us a photo of your window and we will recommend a position. For everything else about measuring, see how to measure plantation shutters.