By Coverly Shutters

The L-Frame

What is an L Frame?

A L-Frame is named after the L-shaped structure of the frame and works in both an inside mount and outside mount application.

“Inside Mount” means the shutter is mounted within the window frame, as opposed to outside it, creating a streamlined look. 

“Outside Mount” means the shutters is mounted outside the window frame, usually used in situations where there is not enough window depth to mount an inside mount shutter.




The dimensions of the L-Frame can be found below:

l frame

The choice to use an L-Frame usually comes out of necessity, but that does not mean it is not still a beautiful shutter. Many homeowners prefer the look of the inside mount L-Frame because it makes it look as if the shutter was built with the house. An inside mount L-Frame is usually the frame of choice when a window has some sort of obstruction on the edges of the window (molding/trim) but still has sufficient depth to mount a frame inside the window opening.

Note: It is rare that a window is perfectly square. A window will usually bow out in one or two corners. A plantation shutter will have exact 90° angles, which leaves small gaps in the window after the shutter is installed. An easy solution to this problem is applying caulk to the edge of the shutter frame, closing the gap between the out of square window edge and the shutter frame.

The minimum depth requirements for a hidden tilt shutter are found below:

Note: These depth requirements are for a hidden tilt shutter.

A standard tilt shutter requires 1/4" less depth.

Painted/Stained Wood

2 ½” Louver

3 ½” Louver

4 ½” Louver

L Frame

2 ¼”


3 ½”


Composite Wood

3 ½” Louver

4 ½” Louver

L Frame

2 ½"



An Outside Mount L Frame will slightly protrude into a room, but still offers a clean, stylish look. If there is not sufficient window depth in a window, an outside mount L-Frame is almost always the solution to the problem.

The required clearance to assure the louvers can tilt without issue for an outside mount L frame depends on the product:

  • Composite Wood: 2" required clearance
  • Painted/Stained Wood: 1 ½”  required clearance

If you are mounting outside of molding and do not meet the clearance requirements, we will "build out" the frame to extend past the obstruction/molding and allow full operation of the shutter. We will be able to see this in the photo uploaded during the design process and add it to the manufacturing process. We will notify you if this is needed for your window.