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Plantation Shutters and Window Sills

For windows with a protruding sill or ledge at the bottom, we often get asked how to take this into consideration when ordering custom plantation shutters. Sills do not restrict your ability to install a shutter or even to have a full 4-sided frame around your shutter unit (or 3 sides for café style shutters which leave the top open).


What is a Window Sill?

We sometimes hear the term sill in reference to the window recess, but we consider a window sill any protrusion from the bottom of the window opening. Sometimes referred to as a ledge or shelf, we consider it a sill if it projects past the edge of the wall or trim. The inside recess (from the edge of the wall or trim back toward the glass) we refer to as the recess depth of the window opening.

More Shutter Terms (Glossary)

Plantation Shutters with a Window Sill

We recommend always having as many frame sides as possible to keep your shutter unit stable and secure as well as perfectly squared to ensure a proper panel alignment.

Full height shutters can have a frame around all 4 sides. The shutter panels have recessed magnets at the top and bottom which catch the top frame piece and bottom frame piece to help keep the panels tightly closed.


Café style shutters cover only the lower portion of your window opening, so the top is always kept open without a frame piece going across the top. For this reason, the bottom frame is essential with café style shutters. The frame sides for café style will always be left, right, and bottom.

Tier on tier style shutters will always require a 4-sided frame. Because your tiers are split, and multiple panels hang above and below one another, the shutter frame will make your installation easier and minimize the number of adjustments needed over time. Tier on tier style takes more adjusting for proper panel alignment, with the top tier relying only on the magnets at the top catching the top frame piece & the magnets at the bottom catching the bottom frame piece.

What to Consider for Inside Mount Frames

If you are doing an inside mount with an L-Frame, there is no need to make any special requests or adjustments to account for your window sill. The L-Frame is a square frame that will fit completely inside the recess of the window opening and does not require any modifications if you have a protruding sill at the bottom of the window opening.


For an inside mount with a Z-Frame, you will want to select the “sill cut” option when ordering your frame. Z-Frames have an overlapping trim that surrounds the window opening (ideal for windows without any existing trim or molding). The sill cut option removes the overlapping lip from the bottom frame piece leaving you with a flat bottom frame that can rest across the sill. You can find this illustrated on page 7 of our measuring guide.

Inside Mount Measuring Guide >>

What to Consider for Outside Mount Frames

For an outside mount on a window with a sill, an L-Frame is ideal. It is already flat at the bottom and does not require any modifications for a sill. When reviewing your outside mount order, our shutter experts will inquire if your window has a sill and how far it protrudes, so we can determine how to pre-drill the mounting holes in your frame (or omit the pre-drilled holes if the sill cannot be drilled into).


When measuring for outside mount, if your window has a sill, you will not need to include the width of the bottom frame piece in your measurements.

You can also use a Deco Frame to add the appearance of a decorative molding surrounding the shutter unit. Our Classic Poplar Hardwood range offers a sill cut for the Deco Frames, so you can still opt for a frame around all 4-sides with a sill cut to flatten the bottom frame piece.


Alternately for Deco Frames with a sill, you can choose “left, right, top” for your frame sides. Our American Polyvinyl and American Hardwood ranges do not offer the sill cut option on Deco Frames, so you would need to select a 3-sided frame in this instance.

Outside Mount Measuring Guide >>

When to Use a 3-sided Frame

As mentioned above, café style shutters will always use a 3-sided frame.
Occasionally for full height shutters, you may not be able to or may not want to use the full 4-sided frame. We strongly recommend a 4-sided frame whenever possible for ease of installation as well as longevity and stability of your shutters.

Some circumstances, however, may prohibit use of a bottom frame piece. These include patio door shutters, where the bottom frame piece may pose a risk of tripping over when stepping out the door, or some casement windows with a protruding crank handle at the bottom.


Even with a marble or granite sill you can still use a bottom frame for support and simply request no pre-drilled holes in the bottom frame piece to avoid having extra holes in the frame that you don’t end up using.

If you use your window sill for storing or displaying items and want to keep the sill free and clear when your shutter panels are opened, you can opt for a 3-sided frame. Keep in mind you may need to make extra adjustments to keep the frame level while installing and adjust the hinges and panel alignment over time. You may also see more light coming through underneath the shutter, as a bottom frame piece has a light blocking piece that goes behind the shutter panel to minimize light seepage.


Whenever in doubt as to the best frame option for your window, just reach out to our shutter experts by phone, email or online chat. It may be easiest to email us a picture of your window where we can see the full window opening to make our best recommendation. Be sure to pull back any existing window coverings so we can see any existing trim, sills, and the inside of the window recess. We are here to help!

This post was brought to you by Yasmeen, one of The Shutter Store USA's experienced shutter consultants. Get in touch today for more advice on finding the best frame option for your window. If you're still unsure and have any questions, our friendly team of shutter experts are a call, chat or email away! Upload a picture of your window with your order or send it in to our support team for help designing your perfect shutters. We are here to help!