Even the best-designed RTA kitchen is likely to face just one small issue towards the end of its installation - gaps.
It could be that the wall isn't completely straight. Or maybe the run doesn't reach the corner. Or there might need to be some additional space left for a cabinet door near a wall or an appliance. This is precisely where cabinet filler strips are needed.
While not exactly an interesting part of any kitchen design, cabinet fillers play a critical role in achieving a great outcome. A well-installed filler strip will make your cabinets look like they were made in place, help with opening doors and drawers and cover those minor gaps that are inevitable in any home setting.
Installing cabinet filler strips is a useful skill if you are planning to install RTA kitchen cabinets on your own, especially when working with standard cabinet sizes from ready to assemble cabinets.
What Are Cabinet Filler Strips?
Cabinet filler strip is a thin strip used for filling spaces in between cabinets, walls, appliances, or angles. Typically, filler strips are designed in colors matching the cabinet door or cabinet finishes so that after installation, they become part of the kitchen decor.
Ideally, all the walls should be perfectly straight and the cabinets should fit just fine. However, practically, that is almost impossible in most kitchens. For example, walls tend to bow sometimes, corners might not be perfect right angles. Additionally, floors and ceilings may not always be level and there needs to be space for appliances.
Filler strips for cabinets will be found:
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Between an end cabinet and a wall
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Adjacent to a refrigerator or range
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Between corner cabinets
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Beside blind corner cabinets or lazy Susan cabinets
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Around tall pantry cabinets
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Where more room is needed for the swinging open of a cabinet door
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On walls that are not level and the cabinet will not fit snugly up against the wall
RTA cabinets in particular often need fillers because cabinet sizes are standardized. When buying kitchen cabinets factory direct, you usually work with regular-sized cabinet boxes and use fillers to complete the final space.
Why Cabinet Fillers Matter in RTA Cabinets
Though a filler strip seems a minor part, it plays its role in aesthetics as well as functionality.
Firstly, it adds aesthetic value since without a filler strip, an opening between the wall and the cabinet will appear unprofessional. Any tiny dark opening will be visible when the countertop, back splash, and lighting are mounted.
Secondly, filler strips improve functionality of cabinets. For instance, when the cabinet is mounted immediately to the wall, its doors will touch the wall before they open fully. Therefore, a filler will give space to open it.
Thirdly, the use of a filler strip can add custom look to any RTA cabinet arrangement. Since most people do not pay attention to the filler, it adds only additional professional appearance to the cabinets.
Before You Start: Plan Where Fillers Are Needed With a Free Kitchen Design Service
Take a careful look at the whole cabinet layout before any cutting is done. If you are unsure where fillers, panels, or moldings should go, using online kitchen design services can help you plan the cabinet run more accurately before installation.
There are some fillers that can be easily identified. If your row of cabinets ends on a side wall, then the most probable place for a filler will be there. There are also some fillers that serve functional purposes. Some fillers like refrigerator panel, pantry door, or corner cabinet could require extra spacing so the doors would not hit each other.
The following are the locations you should pay attention to:
End of a cabinet run
When your cabinets come up against a wall, then you will need a filler strip. This is probably one of the most common filler locations.
Corners
For an L-shaped kitchen, there is often the need for filler at the corners, since this allows doors and drawers to open up without colliding with each other.
Appliances
Refrigerator, stoves, and dishwashers may also need some clearance, and filler can provide breathing room to allow the cabinet door or handle to move around the appliance.
Tall cabinets and pantries
Since tall cabinets are highly conspicuous, any gaps that occur next to them become quite noticeable. The use of fillers helps create a straight vertical line.
Walls that are not straight
If the gap between the two cabinets is wider on top than the bottom, or when the wall curves a little bit, you have to scribe your filler to match the wall.
Tools and Materials You May Need
Specific tools will depend on the layout of your kitchen, but some typical ones needed in installing filler strips include:
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Cabinet filler strips that match
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Tape measure
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Pencil
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Level
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Clamps/cabinet clamps
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Scribing device/compass
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Miter saw
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Table saw/circular saw/track saw
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Belt sander/sanding block
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Drill
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Drill bits for pilot holes
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Cabinet screws/trim-head screws
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Wood glue/construction adhesive
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Shims
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Painter’s tape
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Safety glasses
Do not use drywall screws when securing your cabinet filler strips since these are not suited to this type of finished cabinet work. They might crack the material or give you an ugly end result.
Step 1: Measure the Gap Carefully
First thing to do is to measure the width of the area where the filler strip will be installed.
Don’t just take one measurement. Walls are rarely straight, so take the measurement at the top, middle and bottom of the gap. If you’re working on a wall cabinet, also measure the total height. In case of base cabinets, measure from the top edge of the cabinet box up to the bottom or toe-kick area, whichever the end point of the filler is.
Note the biggest measurement. Normally, you should cut the filler a little wider than the largest gap then trim or sand it down to size.
So, for instance, if there is a 2 1/4 inch gap at the top and 2 inches at the bottom, don’t just cut the filler at 2 inches wide. Cut it closer to the largest measurement then scribe it to the wall.
This is where the difference between a professional-looking installation and a hurried one lies. Be patient.
Step 2: Cut the Filler Strip to Height
Now that you have the height, cut the filler strips to length using the miter saw or any other clean cutting saw.
In the case of base cabinets, the filler strip starts from the top of the cabinet box to the bottom of the face frame or cabinet side. However, in some cases, the filler may extend to the bottom of the toe kick depending on the design of the cabinet.
When dealing with wall cabinets or tall cabinets, make sure that the filler strip is cut according to the cabinet height to maintain neatness at the top and bottom lines.
Check the filler strip for the right height before proceeding with the next step.
Step 3: Rip the Filler Strip to Width
Then, proceed to cutting the filler to the right width.
This should be easy if the wall is level and the opening even. All you need to do is measure the opening and cut the filler to the same width.
However, if the wall is uneven, you may want to cut the filler a bit bigger than required since excess can be removed during scribing and sanding. The most precise cut can be done using a table saw, but many people choose a circular saw with a straight-edge guide.
When working on a prefinished filler, use painter’s tape on the cut line in order to prevent chipping.
Do not hurry and try to make a neat cut; otherwise, you may have problems in concealing the filler.
Step 4: Dry Fit the Filler
Position the filler strip into the opening prior to securing it.
Ensure that there are three elements that are considered:
Whether the filler is level with the cabinet.
Whether it fills the gap entirely.
Whether the cabinet door or drawer operates normally.
It can be secured using clamps to make sure that you check its fit. Step back to observe the cabinets from a regular viewing distance. Sometimes the filler looks right at a closer observation, but when seen from the entire kitchen, it might not seem even.
In case the filler is too tight, sand or reduce it a bit. In case the filler is too loose, measure it again prior to securing anything.
Step 5: Scribe the Filler to the Wall
If the filler meets an uneven wall, you will need to scribe it.
This involves the creation of the contour of the wall from the filler strip so that the installer is able to cut the filler according to the contour of the wall. It gives a clean fit as opposed to making an effort to fit a straight strip into a crooked wall.
In order to scribe the filler,
Install the filler strip into the gap and secure it using the clamps to the cabinet.
Adjust your scribing device or the compass to its widest point of the gap.
Scribe along the wall while creating a mark on the filler strip using a pencil.
Remove the filler strip and sand or cut the mark created.
Check the fit.
It is possible that the fitting process has to be done more than once. This should be expected. This is because it is advisable for the installer to remove material gradually rather than removing excess amount leading to a gap being formed.
For a tight fit, the installer may want to use a back bevel on the wall side of the filler.
Step 6: Attach the Filler to the Cabinet
If the filler is positioned correctly, then attach it to the cabinet.
The best way is to nail into the filler from inside the cabinet box.
Fix the filler using clamps.
Make pilot holes from the cabinet side or from the face frame into the filler.
Fix the filler using cabinet screws or trim-head screws.
Do not overtighten them since excessive tightening may move the filler and scratch the finished surface.
If the filler is a narrow piece, then wood glue or construction adhesive will do the job, provided that there are no stresses on the filler. Otherwise, for wider fillers, it is better to use screws. If the filler is very wide, then adhesive and support behind the panel from the wall should be considered.
In any case, make sure of the proper front reveal before the adhesive is dried or the screws are tightly fixed.
Step 7: Install Fillers Between Corner Cabinets
The process of filling the corner differs slightly from filling the wall since you would work with two faces of cabinets instead of irregular wall surface.
In an L-shaped kitchen, cabinets require space in the corner to avoid interference between doors, drawers and handles. This problem is particularly relevant for base cabinets, lazy Susan cabinets, blind corner cabinets and drawers situated in the corner.
In an inside corner with a very basic design, you may have to use two filler strips that join at a right angle.
It is necessary to measure required filler space on each side.
Then, cut both strips according to the height of the cabinet.
Change the width so the two pieces fit perfectly into the corner.
Join them first if necessary and attach to the cabinets.
For example, if you need 3 inches of filler on each side of the corner and the filler is 1/2 inch thick, one strip may need to be slightly wider so the outside edge lines up correctly.
Open all adjacent doors and drawers before finishing the installation.
Step 8: Check Door and Drawer Clearance
Once you've added the filler, check the cabinets.
Open the doors completely. Take the drawers out. Check around for handles, refrigerator doors, and corner cabinets.
This is an easy task to overlook, but it's important. If the filler looks good but fails to let the door open, it's not working.
Some things to look out for include:
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Wall cabinets
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Trash pull-outs
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Spice pull-outs
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Corner drawer bases
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Refrigerator cabinets
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Cabinets with large handles
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Blind corner cabinets
Make sure nothing is rubbing or hitting.
Step 9: Finish the Edges
Now that the filler is in place, check the edges.
If the filler is prefinished and you have a cut edge that goes behind the wall or cabinet, you may not need any additional finish work. If there is a cut edge that is exposed, it may require touch-up, edging, or molding depending on the type of cabinet line.
For painted cabinets, very small nail holes or seams can often be filled, sanded, and touched up. However, for stained or wood cabinets, take extra care as wood filler and touch-up paint will not always match the factory finish.
If the filler butt joins the wall and still has a hairline gap, a small application of paintable caulk can create a neat transition. Be careful about using too much caulk. The aim here is to finish the line, not to hide a bad cut.
Common Mistakes to Avoid
Cutting the filler too narrow
This is the single most common error. Start off with a slightly bigger fit when the wall is irregular. You can trim down, but you cannot enlarge.
Forgetting about door swing
The filler is not only cosmetic. Ensure there is adequate space for the door and drawers to move freely.
Assuming the wall is straight
It is possible to find slight inconsistencies even in brand new houses. Always measure in multiple locations.
Using the wrong screws
Not every type of screw will do. The drywall variety is not good for cabinetry. Use cabinet screws or trim screws instead.
Skipping the dry fit
Do not glue or screw the filler in position without doing a trial first.
Overusing caulk
A small wall discrepancy may be corrected using caulk. But it is not an alternative to proper cutting and shaping.
Should You Install Fillers Before or After Setting Cabinets?
In most instances, it would be simpler to mount the filler onto the cabinets prior to mounting the cabinets to the wall itself, especially where the cabinets form a run.
But, all kitchens are unique in their own way. If the walls are not smooth, then you must first place the cabinets in their location, measure the exact gap, and scribe your filler.
One guideline that can be followed is:
Mount the cabinets plumb and level first, but do not fix the run in place until you have the fillers measured for fit.
This will give you some room for maneuvering.
How Wide Should a Cabinet Filler Strip Be?
There isn’t one ideal width. It all depends on the layout, cabinet design, clearances for appliances, and wall conditions.
Standard filler widths are about 3 inches, but there are occasions when kitchens will need a narrower or wider filler. A narrow filler can be enough to fill in a gap from the wall. A wider filler can be required next to a pantry, refrigerator, or corner cabinet.
When looking at design principles, try to avoid making a very big filler, if a smaller cabinet can close that gap. But never eliminate all fillers because you want your cabinets to fit tightly. The doors, drawers, and appliances require clearances.
Do RTA Cabinets Come With Filler Strips?
Filler strips for RTA cabinets can be found in the same cabinet line, although they will not always come with each cabinet order. This depends on the type of cabinet and quotation.
When designing your kitchen, make sure your quote includes all necessary fillers, panels, toe kicks, and moldings before installation starts. You can also use a kitchen cabinet estimator to get a clearer idea of the cabinet cost before finalizing the layout. It is more convenient to have your fillers ordered together with your cabinets rather than stopping your project midway due to lack of one piece of filler strip.
If you are unsure about the number of fillers needed, take your time to review your RTA Kitchen design before placing the order.
A Cleaner Fit Starts With Better Planning
While cabinet filler strips can be thought of as a minor component of your RTA kitchen, they play an important role in the end result. They assist in filling any wall voids, increase door clearance, give corner finishing, and add built-in touch to your standard size cabinets.
It all comes down to patience. Measure twice. Make a dry run before installing. Scribe properly if the wall is not straight. Use the right type of screw. Test each adjacent door and drawer before declaring the task accomplished.
A professionally installed cabinet filler strip will not attract any attention to itself. It will discreetly give the entire kitchen a cleaner look.
This is what it all comes down to: not simply filling a gap, but create a complete kitchen.