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How to Install Cabinet Filler Strips

While professionals have the right tools and know-how, DIY cabinet installers may not know how to install a filler strip properly. But after installing countless kitchens there are a few tricks I’ve learned on how to install cabinet filler strips the right way

Installing filler strips comes down to a few key steps:

  • If needed, cutting the filler strip to the proper width
  • Attaching the strip to the cabinet using clamps and then screws
  • Temporarily placing the cabinet to check for fit
  • Scribing the filler strip to let it match to other cabinets or the wall
  • Hiding any gaps with (my favorite) color putty 

While this is a seemingly simple step in a cabinet installation project, it can be the most difficult to do right. In this guide learn the tricks and tools you’ll need to do a proper job.

How to Install Cabinet Filler Strips

1. Layout the Cabinets First

Creating Cabinet Layout

Before installing any filler strip make sure to layout all cabinets both uppers and lowers to make sure both upper and lower cabinet spacing is taken into account.

Since the upper cabinets are typically installed first, the filler strips on the upper cabinets MUST be properly laid out to match the lower cabinets.

A great example of this layout preparation is needing to align the microwave cabinet gap directly over the range below. If you space the upper cabinets and don’t match the lower cabinets your range and microwave will be out of alignment.

Once you have the layout in hand, note the widths of each strip for reference when installing.

2. Cut the Filler Strip to Width and Length

Dust Control for Woodworking Safety

Next up is making sure the filler strip is the right length and width. 

Fortunately, most factory cabinets you’ll find the lengths are matched to your cabinets.

But, that leaves the trickier job of adjusting the width to you. Not sure how to cut the strip? Here’s a few options:

  • Use a table saw if you have access to one
  • A circular saw with a rip cut track guide is a great (inexpensive option)
  • For less than a 1/4″ in width adjustment a belt sander is slower (using a 40-60 grit belt). Use a wood scribe to mark a line.

3. Connect the Filler to the Cabinet

Connecting cabinets with a cabinet claw

After making sure the strip is the right size and cut to dimension you’ll need to install it to the edge of the cabinet.

There are a few options for this step, but I recommend:

  • Using a cabinet claw to connect the face frame to the cabinet
  • Or, use a wood cabinet clamp to hold a cabinet filler to a frameless cabinet.

After the filler strip is clamped to the cabinet, use the guide bushing and a LONG 1/8″ drill bit to drill a pilot hole into the filler. For my projects, I like to use a GRK trim head screw, which you can learn more about in our guide to cabinet screws.

4. Install the Cabinet

Fastcap Cabinet Jack Holding Cabinets

Once the filler strip is attached to the first cabinet, simply install the cabinet and repeat these steps as needed.

5. Hide Gaps With Color Putty

color putty to fill holes and gaps in filler strips

Lastly, cabinet installation is all about tricks of the trade.

And one of my secret weapons is using Color Putty to hide any gaps between cabinets or nail holes in the crown molding or toe kick.

How to install cabinet filler strips against the wall

Cabinet Filler Strip Tool - Profiler+

Because filler strips can cause visual imbalance, installing them against the wall is a great way to offset their visual impact. And by doing this you avoid a cabinet-to-cabinet mismatch such as an extra gap between one set of doors vs. another.

When installing cabinets against the wall a scribing tool will guide your pencil and leave a perfect contour on the filler strip for sanding.

Steps:

  1. Cut the filler strip to length with a miter saw.
  2. Rip the filler strip to width with a table saw and fine tooth blade.
  3. Clamp the filler strip to the cabinet using a cabinet claw.
  4. Drill a pilot hole completely through the cabinet frame and partway into the filler strip. Tip: use a drill bit the size of the screw shaft (minus threads).
  5. Use a face frame screw to connect the strip to the cabinet.
  6. For upper cabinets, set the cabinet on a cabinet jack.
  7. Using a sharp pencil with a scribe, level the cabinet and then run a pencil against the wall and down the entire length of the cabinet filler. 
  8. Use a belt sander to remove material on the wall side of the filler strip
  9. Fit the cabinet and make minor adjustments to the filler strip as needed for a perfect fit.
  10. Hide any small gaps with (my favorite) Color Putty by working it into any gaps with your fingers and wiping away the excess.

How to Install Filler Strips on Upper Cabinets

Install Cabinets by Myself Adjusting Door

Installing filler strips on upper cabinets takes one of two forms:

  • Fitting strips between cabinets
  • Or, installing a strip between the wall and cabinet

While installing filler strips on upper cabinets is similar to installing against the wall you’ll want to make sure you use a cabinet jack and scribe. 

Tips:

  • Start from corner cabinets and work your way out
  • Try to hide filler strips in the corner
  • And, make sure to line up the upper layout to the base (eg. oven alignment)
  • Lastly, don’t be afraid to split the filler strips in two and use multiples to reduce the visual impact

Installing filler strips between cabinets

Cabinet Clamp for Installing Filler Strips

This is done exactly the same as up against the wall, with the luxury that you can install the filler strip to the cabinet first, and then choose to sand (or plane) the next cabinet to match. 

Steps:

  1. Cut the filler strip to length with a miter saw.
  2. Rip the filler strip to width with a table saw and fine tooth blade.
  3. Optional but preferred to remove any saw tooth marks: run a portable planer down the filler strip for a perfect edge.
  4. Clamp the filler strip to the cabinet using a cabinet claw or cabinet clamp.
  5. Drill a pilot hole completely through the cabinet frame and partway into the filler strip. Tip: use a drill bit the size of the screw shaft (minus threads).
  6. Use a GRK face frame screw to connect the strip to the cabinet.
  7. For upper cabinets, set the cabinet on a cabinet jack.
  8. Fit the cabinet and make minor adjustments to the filler strip as needed for a perfect fit.
  9. Hide any small gaps with (my favorite) Color Putty.
Unlike a wall fit, you shouldn’t need to scribe or use a belt sander other than minor adjustments.

Planning your cabinet filler strip widths

Cabinet Filler Strip

While most cabinet professionals would prefer to not use a cabinet filler they sometimes can’t be avoided. The #1 issue with filler strips is they can create a visual imbalance between cabinets.

That makes planning where the filler strips go and how best you can hide them is the first priority.
 
Here are a few filler placement tricks:
    • Use corners and walls to hide filler strips
    • Avoid putting large filler strips in the middle of cabinet runs
    • Rip filler strips in two and use multiples to balance their visual impact
    • Make sure upper and lower cabinets are planned together
    • Finally, before installing the first filler be sure to layout all strips and check plans and room dimensions  to ensure everything will fit.

Finishing cabinet filler strips (optional)

General finishes arm-r-seal satin wood sealer

I like to finish the cabinet strips prior to installing them. By doing this you will ensure the strip is a good match with the neighboring cabinet.  Also, having the filler strip “free” to work on will let you easily stain, paint, or apply urethane or other sealants to it.  Finally, you also get a chance to make sure it matches the cabinets before you install it.  Especially if it didn’t come with the cabinets.

Tip:  Looking for a wipe-on wood sealer that drys in an hour and is simple to apply?  I have used General Finishes Arm-R-Seal for almost twenty years and it always produces a quick and high quality finish.  Dry time in under an hour is a huge time saver.

Finding cabinet filler strip material (optional)

Don’t have a piece of wood that came with the kitchen?  Don’t worry, there are a few options to get what you need. 

To find cabinet filler strips you have a few options:

  • Call the manufacturer and order pre-made, finished strips that match your kitchen wood and color.
  • If you are painting the cabinets later, head to a local Home Depot or Lowe’s and grab a filler strip from their kitchen area.  If it’s finished just install it backward if needed.
  • For natural or stained cabinets and the manufacturer isn’t an option, then find a hardwood supplier such as Rockler (a favorite of mine who has every hardwood imaginable) or check on Amazon.  Sherwin Williams or another paint store can help with a match.
  • If you are ordering cabinets plan to over-buy on these filler strips upfront.  A few dollars now will save you a headache later on.

Frequently Asked Questions on Installing Filler Strips

Frequently Asked Questions

How do you scribe a filler strip?

First, cut the filler strip to the required width and attach to the cabinet. Next place it against the wall and use a sharp pencil or scribing tool traced against the wall to transpose the wall curve to the filler strip. Lastly, remove the cabinet and use a belt sander to sand away the excess. I prefer to run the belt sander at a negative angle to the face of the frame to give it a slight “point”. Repeat the sanding step as needed.

What is a cabinet filler strip?

A cabinet filler strip is a piece of wood inserted between two cabinets to allow factory-sized cabinets to fit a wall of any length. A filler strip can be placed between two cabinets or against the wall to “fill” the empty space between cabinets.

How do you fill the gap between two cabinets and the wall?

A filler strip is used to fill the gap between two cabinets and the wall. Due to factory cabinets coming in standard widths, such as 24 and 36-inches, they will not fit walls with varying odd/fractional dimensions. Filler strips are almost standard in most kitchen cabinet installations that do not use custom-built cabinetry.

How do you hide gaps between the filler strip and the wall?

First, a proper installation shouldn’t have a gap. However, if a gap is present it can be filled with white paintable caulk and painted over. And gaps in filler strips between cabinets can be filled with a rub-in and wipe off putty (that doesn’t require sanding).

Summary

Hopefully this article helped your cabinet filler strip installation. Be sure to subscribe and check out the following articles for other tips and tools.

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  • About the Author
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( Woodworker )

Eric has been a professional woodworker for over thirty years and has worked in small cabinet shops making everything from kitchen cabinets to hand-made furniture. Now working from a home woodworking shop Eric is sharing his passion for woodworking, tool advice and how-to knowledge from his Minnesota-based woodshop.

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