How to Install a Farmhouse Sink

If you’re looking for a way to update your kitchen, consider a farmhouse-style sink. We’ll walk you through the steps to install one.

Sink Types

Farmhouse sinks can be mounted three different ways.

Top Mount Sinks

They’re the easiest to install. There’s a flange that sits on the countertop just like a regular sink. They can be installed on any type of counter surface.

Flush Mount Sinks

They sit even with the top of the counter. They typically require a solid surface or custom-made laminate top.

Undermount Sinks

These sinks sit completely underneath the counter. They require a waterproof top that’s custom cut for the sink and faucet. We’re using an undermount sink for this how-to.

Instructions

Step 1

For this project, we installed a KOHLER Whitehaven Sink that’s made from enameled cast iron. Stainless steel farmhouse sinks are available too. These sinks are heavy and require extra support. This is definitely an advanced project.

The plan for this project is to remove the old sink and countertop, prep the cabinet, install the new sink, set the new counters, then install the faucet and connect the plumbing.

Measure

If your new top is stone, a countertop installer is going to measure the cabinets and sink to create a custom top. Some installers are going to require a farmhouse sink to be installed before measuring. Have your faucet, soap dispenser or any other accessories that need a hole drilled on-site for them. It’s also a good idea to ask the installer what you need to do to prepare for the installation.

One of the great features of the sink we used is that it doesn’t require a custom cabinet like some farmhouse sinks with taller apron fronts.

Check the instructions online before picking up the sink to make sure it’ll fit. Most instructions will include measurement requirements of the cabinet. In this case, we measured the following:

• Width of the cabinet

• Distance from the top of the cabinet to the bottom of the drawer opening or screw holes to make sure it was shorter than the apron

• Distance from the top of the cabinet to the doors to make sure the apron wouldn’t interfere with the doors

If your sink is near a corner, make sure that adjacent drawers or dishwashers will clear the apron front.

Step 2

Remove Plumbing and Sink
To begin removal of the old sink, start with the plumbing. Take a few pictures of the drain setup just in case you need it later for reference.

For a typical sink removal, turn off the water and disconnect the plumbing. Also remove the disposal. Remove the sink clips underneath, cut the sealant on top and pull out the sink.

All of our plumbing is at a good height for a sink installment, but you might have to lower yours to clear the bottom of the sink basin. You’re going to be doing this job inside a cabinet so you might want to call a pro.

For PVC, mark your length and cut with a hack saw or PVC cutter. Remove the burrs with 80-grit sandpaper — outside the pipe and inside the pipe fitting. Dry-fit the PVC drain right now, and secure it when the sink is in place. For copper pipes and water valves, use push-connect fittings.

Cut the copper with a pipe cutter. Secure it, spin it and gradually tighten it until it cuts through. Deburr the pipe with a special tool. Then slide the push-connect fitting.

Step 3

Remove the Countertop

If your countertop is screwed down, use a screw gun to back out the screws. If it’s glued down, use an oscillating saw to get between the counter and the cabinet.

Level the Cabinets
Next make sure the cabinets are even and level. Use shims if needed.

Prep the Cabinets
To make access easier and prevent damage, remove the doors. If you have false-front drawers, remove them as well as any screws or brackets that might be in the way.

Step 4

Cut the Cabinet
Our sink came with a template to cut out the front of the cabinet. Before attaching a template, use painters tape to mask off the areas that are going to be cut so they don’t become splintered with the saw.

Mark the center of the cabinet for the template. We have a 36-inch cabinet, so we marked it at 18 inches. Then line up the cutout template, and tape it in place. Trace the template onto the cabinet and remove the template.

Now cut the outline with a jigsaw or an oscillating saw. Sand it smooth if it’s a little rough.

Step 5

Add Cabinet Supports
A farmhouse sink needs supports attached to the inside of the cabinet because it’s heavy. Some can weigh over 300 pounds when filled with water.

The top of the sink needs to be even with the cabinets so the counter will sit correctly. Measure the thickness of the sink and transfer that to the cabinet walls. Our instructions say the supports should sit 5/8 of an inch below the top. Use a straight edge to mark the line. Apply construction adhesive to the horizontal 2-by-4 supports. Hold them in place and secure them with screws.

Now add vertical supports that extend to the base of the cabinet.

Step 6

Set the Sink
You’ll need an extra set of hands to help set the sink. If it’s a little low, use shims to raise it. Then double-check the height.

Step 7

Set the Countertops
Now that the sink is in place, the countertop installers will set the countertop. They’ll apply sealant along the cabinet tops and sink top, and set the countertop in place. Check with your installers on cure time before connecting the plumbing.

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