Part 2: How to Install DIY Built-In’s with Kitchen Cabinets

This is the second part in our series covering our Fireplace installation and the project that completely transformed our main living area! In the previous step we covered how to install the IgniteXL Bold Built-in Linear Fireplace. If you missed that section jump on over there to see everything we’ve done so far in this project.

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    Table of Contents

    Recap & The Sideboard

    One of my favorite projects that I’ve done has been my DIY Sideboard using Kitchen Cabinets. It’s also been one of your favorite projects with well over 10.5M views on Instagram and TikTok combined. With that in mind, I set out to recreate the sideboard on a more grand scale. In the last post we talked about the focal point, the fireplace, but this post pulls the whole project together. It connects, the sideboard, and my kitchen island and it completes this grand project.

    The sideboard was built using stock upper kitchen cabinets connected together, intricate millwork, matching drawer pulls, and a custom stain. The built-in’s are built in almost the exact same way, just combined with DIY shelves above.

    Built-In’s Installation

    Tools and Supplies

    Kitchen Cabinet Installation

    To watch the in-depth version of this process, please click here.

    The space on both sides of our fireplace was 57 inches. That left enough room for a 36 inch cabinet, an 18 inch cabinet, and 1.5 inches of space on each side. The first step in installing the cabinets was to remove our laminate flooring so that the floating floor wouldn’t be pinned down.

    The next step was cutting 3 4×4’s to a length of 12 inches to support the cabinets underneath. These supports also go the full depth of the cabinet so that the baseboards can be nailed to them. We used 3 of these 4×4’s, one on each end and then one in the middle split between each cabinet. We used construction adhesive to attach the 4×4’s to the wall. The weight from the cabinets and built-in’s will really keep the 4×4’s in place, especially once the cabinets are screwed to the wall. You could also screw the cabinets to the 4×4’s from the inside if you were really concerned about them moving.

    Once the 4×4’s are in the correct position and the cabinets have been perfectly centered, it’s time to screw the cabinets to the wall. Find a stud on the wall and screw the cabinets into the stud. This will keep the cabinets from moving anywhere as you build the shelving. We found that to keep the spacing consistent on each side that it was helpful to use 2×4’s cut to 11 1/4″ (short of the face of the cabinets by 3/4″ so a front piece of oak plywood could be applied) and nail them to the side walls with a framing nailer.

    Built-In Side Panel Installation

    Now that the cabinets are installed, the next step is to cut more 2×4’s to a length of 11 1/4″ and nail them to the side walls, in studs, all the way to the ceiling. This will keep the spacing consistent from the floor to the ceiling.

    Once the 2×4’s are installed the next step is to install the side oak plywood panels. The side panels will be cut to a depth of 11 1/4 inches (not 12 inches which is the depth of the cabinets). These side panels are short because a front piece of plywood will be placed over the edge and the 2×4’s. A circular saw and the kreg jig circular saw track (a necessity) are used to cut the plywood in nice straight lines, while a miter saw can be used to cut the pieces to the correct length.

    Before nailing any side pieces, use a spade bit and a jigsaw to cut out any outlet holes, or any holes needed to run Romex for lighting. On both sides of the fireplace we made holes in the top of the side panels for the Romex wiring and to install the lights, as well as outlets and light switches. Once your configuration is complete, nail the side panels to the 2×4’s using a finishing nailer.

    Middle Panel Installation

    Next, the middle piece will be installed. Both sides will be cut to a depth of 11 1/4 inches, just like the side panels. In between the two panels 2×2’s were used to keep the spacing consistent from top to bottom. The plywood was connected to the 2×4’s using a finishing nailer. You’ll want to cut these pieces such that the height of the panels snugly fits between the cabinets and the ceiling. This is mainly so that the panel stays in place before the shelves are put into position.

    Back Panel Installation

    Once the side panels and middle panels are installed, next comes the back panels. Once again cut any holes in the back panels that will be needed to install lights, light switches, or outlets. This entirely depends on where you are pulling power from for your lights and where you plan to install outlets and switches. The back panels don’t need to go all the way to the ceiling because they will be covered by the header. Cut the panels to the correct width and height, depending on your situation, and install using a finishing nailer.

    Built-In Header

    Once the back panels are installed, it is time to install the front piece at the top of the shelves. We decided to have a piece that was 9 inches from the ceiling to the bottom to allow enough space for crown molding a for a light. Cut the plywood to the correct length. Use a spade bit and a jigsaw to cut a whole for the light. Install a metal electrical box that fits between the 2 inches of space in between the middle panels. It might be easier to install the electrical box once the light has been wired and then sliding it back in between the panels.

    Built-In Shelving Installation

    All shelves will be cut to a depth of 11 1/4 inches. This is so that a front piece of plywood can be placed across the front, hiding the spacing between the two shelf panels and making it flush with the cabinets installed earlier. We decided to install 3 levels of shelves on each side with a consistent space between them. Depending on the height of your ceilings, and the height of your top header (where the light goes).

    Install 2×2’s for shelves

    All of the shelves used 2×2’s to keep the spacing consistent from shelf to shelf. These 2×2’s will also support the weight placed on the shelves. With 3 levels of shelves on two sides we cut 16 2×2’s of length 11 1/4″ and then 8 2×2’s the width of the shelves minus the two outside 2×2’s. Mark the side panels with the locations of each of your shelves and install the 2×2’s using a framing nailer. It was helpful to use a level to make sure that every shelf is level. These 2×2’s will be nailed into the side panel of oak as well as some of the 2×4’s that were installed behind them, that were nailed into studs.

    Once one side is nailed in and level, now move to the 2×2 on the opposite side of the shelf. Use a scrap piece of wood, the width of the shelf, and a level to nail the 2×2 on the opposite side of the shelf of the first 2×2. Using the scrap wood and level ensures that the entire shelf is at the same height and will be level. Once both side 2×2’s are installed the back 2×2 is fairly straight forward. Just line both ends up with the side 2×2’s and you are good to go (you can also check it with a level).

    Install Plywood Shelf Panels

    Once all of the 2×2’s are installed it’s time to start installing the oak plywood shelves. To complete the installation you will need 14 pieces cut to a depth of 11 1/4″ and 2 pieces cut to a depth of 12″. The two 12″ pieces will be the bottom shelf that are placed on top of the cabinets. You will also want to not cut the shelfs to exactly 12″ but a few millimeters short so that the oak banding can be installed flush with the cabinet. Use a finishing nailer to install each of the shelves and nail them into the 2×2’s.

    Built-In Face Plates

    The next step is to install the front pieces of plywood across the fronts of all shelves, down the side panels and middle separation, and down the sides between the wall and the cabinets. The front pieces should be flush with the front of the cabinets. For any exposed sides of plywood make sure to cut them just a couple of millimeters short so that the oak banding can be place across the exposed side, making the rough inside smooth. Measure, cut with a circular saw, and a miter saw, each piece and nail them to the shelving using a finishing nailer.


    Now repeat the entire process on the opposite side of the fireplace so that the built-in’s are symmetrical. Because the fireplace was centered in the wall the measurements should be the exact same on each side. It’s usually easiest to repeat the process at this point because the process and tools are fairly similar in each step, whereas going forward the tools will change.

    Wood Filling

    Wood filling comes next as you are bound to have some gaps here and there. Unfortunately, no walls or ceilings are perfectly straight and so you always end up with slight gaps. Use styrofoam to fill large gaps and then use wood filler over the top. Fill in any other holes or level discrepancies with wood filler. Once the wood filler has dried, sand down the wood filler so that the gaps are all filled in and smooth. There is usually some slight gaps between the banding and the shelves that need to be smoothed with wood filler. Repeat the process on each side.


    Once you have wood-filled all gaps and nail holes, you will sand every inch of each side three times. You will start with an 80 g. sanding paper on your sander, then proceed to 120 g., and then last use 220 g. to ensure that each side is ready for finishing work and that the surface is smooth.

    We found that it was best to attach our sander to a portable shotvac to prevent minimal sawdust from spreading throughout our main living room. There will still be sawdust, but the shotvac reduces the amount quite a bit.

    Oak Edge Banding

    Next in the process is to cover all exposed edged with edge banding. This banding is installed using an iron. When installing the banding it’s helpful to leave the pieces a bit longer than expected because it shrinks just a bit. There is a lot of edge banding to install, around every shelf on each side of the face plates as well as the front of the bottom shelf and either the bottom of the header or the front of the top (under the header) depending on how they were installed.

    Finishing Touches and Staining

    We felt that removing the cabinet doors and doing them separately was a little bit easier to do, especially since the millwork must be installed on them. Before beginning staining the built-in’s, we reinstalled the laminate flooring, then installed the baseboards and the crown molding so that they could be stained the same color.

    Custom Paint

    The staining process involves two parts, this is different than the sideboard but simpler. This process yields the same color as the sideboard. The first step is to paint all of the wood, including the cabinets with the custom color-matched paint (see custom numbers in tools & supplies). Because the plywood and the cabinets were slightly different colors this normalizes the colors between all of the wood.


    If you would like to watch a video of this process, click here.

    Once the custom paint dries, the stain comes next. The custom paint doesn’t cover the wood grain once the stain is applied. Use the Briarsmoke Verathane Gel Stain and apply using a stain brush and wipe the excess stain with stain cloths to achieve the desired color. To get a darker color apply more, and a lighter color a bit less and let the custom paint come through a bit. Use this stain process on both the cabinet doors and on the built-in shelves.


    For the millwork on the shelves install the chair molding around the edges and the screen trim down the middle and in thirds vertically. See this video here for further information. In the rectangles of the cabinet doors, Urbane Bronze will be used to color the doors a darker color. The molding will have the same color and stain as the built-ins and the rest of the cabinets. The chair molding can also be added to the edges of the built-ins to tie the cabinet doors and built-ins together.

    Soft Close Hinges

    Once the cabinet doors have had the millwork installed, have been stained, and have been painted, you can upgrade the doors with soft close hinges. One thing we didn’t do with the sideboard, that we will be upgrading after this project, is swapping out the hinges for soft close ones. This has made a dramatic increase in the quality of the cabinets. Remove the old hinges using a drill and install the new hinges in their place. Finally, reinstall the doors on the cabinets.


    Before connecting the lighting or pulling power, make sure to turn off the breaker. Next install the lighting above the center shelf divide so that the light is centered and in the desired position. Sheath and strip the wires and then using wire nuts connect the light to the 14/2 Romex. Install the final screws that hold the light in position.

    And there you have it!

    Since we are always working on new things here, I like to share snippets of these projects and other parts of my everyday life craziness on my Instagram account. Come stop by!

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