Farmhouse Sink Installation Guide

Stonewood Granite and Quartz

Prepare the Work Area

To get the sink ready for removal, turn the water lines off. There are usually two valves inside the base cabinet under the sink: one for hot water and one for cold water. 

After closing both the water valves, disconnect the fittings. At this point, the water lines should be free, and you can remove them from the supply lines. They will still be attached to the sink and faucet, so let them dangle.



The next step is to remove the drain lines from the stink. Use a small bucket or a towel to catch the water inside the P-trap as you remove it. With the plumbing disconnected, you can move on to removing the sink.

Remove the Old Sink

Remove any fasteners holding the sink in place. They are usually inside the base cabinet, underneath the sink. Use a utility knife to cut through the bead of silicone around the sink. The sink should now be free to lift straight up and out of the countertop. If it doesn’t come out quickly, use a flat pry bar to break it loose.

Remove Countertops

First, remove all the lower cabinet drawers, doors, and all contents. Next, remove the screws in the base cabinets holding the countertops to the cabinetry. Then, use a utility knife to cut through the silicone beads to help free up the countertops.

One or two people can generally handle most laminate countertop removals. But, if you have tile, concrete, or stone countertops, you’ll want to get as many friends as possible to help lift them.

Build a Support Frame

Most farmhouse sinks are extremely heavy, and the Fireclay sink in this example is no exception. Around 85 pounds! While that may make it a little more challenging to handle, it makes up for the weight with its durability! To install the farmhouse sink properly, you must build a frame out of 2x4s to support the weight.

To retain as much usable cabinet space as possible, we built the frame by screwing 2x4s right to the sides of the base cabinet. This approach kept the framing from eating into the storage space below the sink. For an ‘under-mount’ sink, the top of the sink needs to sit ⅛” under the countertop. 

To determine how tall your framing needs to be, use a measuring tape to measure the inside height of the cabinet minus the height of the sink, minus ⅛”. Lastly, ensure the 2×4 frame is a tight fit behind the cabinets. You will need to mount a trim board to this 2×4 in a later step.

Cut Into Existing Cabinets

This part can be a little intimidating, but it’s pretty easy. Remove the false front panel (the fake drawer under the old sink). These panels usually hold in place with little spring clips – pull hard to remove. (Important: save the false front panel to use as a trim board in a later step.)

Carefully measure and mark the front of the cabinet where the new farmhouse sink will protrude through the front. Plan a ¼” gap on either side of the sink to give yourself some wiggle room. These cuts do not need to be 100% perfect because you will cover the gaps with a trim board. 

Double-check your measurements to be sure the sink will be centered before you cut! If everything looks good, grab your Sawzall and start cutting! Keep the pieces you remove. You will repurpose these after installing the sink. Cabinets with doors and countertops removed with the under sink cabinet cut into to make room for the farmhouse sink.

Install the Farmhouse Sink

Now that you have a frame in place and a cutout for the apron front, you only need to slide the sink right in. The sink rests on the framing for now – no need for fasteners or adhesive. The ¼” gaps on both sides of the sink leave room for final adjustments when installing the countertops.

Use a bubble level to ensure the sink is level in all directions so that water drains properly. If needed, you can make adjustments with shims.

Reconfigure The Under Sink Base Cabinet

To get the sink ready for removal, turn the water lines off. There are usually two valves inside the base cabinet under the sink: one for hot water and one for cold water. 

After closing both the water valves, disconnect the fittings. At this point, the water lines should be free, and you can remove them from the supply lines. They will still be attached to the sink and faucet, so let them dangle.

The next step is to remove the drain lines from the stink. Use a small bucket or a towel to catch the water inside the P-trap as you remove it. With the plumbing disconnected, you can move on to removing the sink.

Install Trim Around the Sink

Use the old false front panel (from step #5) to cut new trim boards around the sink. Measure and cut one for each side and one for the bottom. We glue them together to make the trim boards look seamless before installing them.

Using the old spring clip hardware made putting it up in one easy step easy. (Another option would be to use finishing nails or adhesive to hold the trim boards in place.)

**We chose to reuse the existing trim pieces to match our cabinets. If you are planning on painting or refinishing your cabinets, there’s no need to repurpose the old parts. If possible, it would be easier to create the base cabinet and trim pieces in steps #8 and #9 from scratch.

Cut Cabinet Doors Down to Size

Measure the new opening for your cabinet doors. Use this measurement to decide how much to cut the doors down. Ensure the bottom of the cabinet doors will line up with the other cabinet doors in the kitchen. Our doors needed to be cut down by exactly 3".

We decided to cut a piece out from the middle to keep the existing look on the face of the cabinet door with the raised frame. This cut allowed us to shorten the door overall without losing the top or bottom frame. Next, remove all hardware from the doors, including pulls and hinges. 

Use a table saw to cut the top of the cabinet doors off in an inconspicuous spot – in our case, this was right below the top frame (as seen in the photos above).

Then, cut 3" (or your measurement) off the door's body. These cuts must be precise, using a high tooth count finish blade to make the cleanest possible cut. You'll need a track kit if you have to make this cut by hand with a circular saw.

Use wood glue and dowels to join the top frame of the door to the cut-down bottom piece. To hold the pieces together while the glue dries, use ratchet bar clamps for 24 hours. Reinstall the door pulls and hinges, and reattach the new doors! Now, all that's left to do is hook up the plumbing and reattach the garbage disposal.