How To Install A Drop In Cast Iron Kitchen Sink

Cast iron is hardy, long-lasting material for kitchen sinks. There are two layers: the foundation, which is a heavy iron alloy, and the top layer, which is a thick enamel. The two layers create a sturdy yet attractive sink. 

These sinks come in various colors, styles, mounting types, and price ranges. This article focuses on drop-in cast iron sinks, so stick around to learn more! 

How To Install Your New Cast Iron Kitchen Sink

Installing a cast iron sink isn’t a complicated process. However, the sink’s weight may require a few extra hands for the installation. Of course, if you’re not comfortable installing the sink yourself, you can always outsource the project to a professional.

American Standard 77DB30190.308 Delancey 30x19 Double Bowl Cast Iron Kitchen Sink, Brilliant White

If you’re tackling the project yourself, here’s what you’ll need:

  • Chalk 
  • Level
  • Drill
  • Spade drill bit
  • Jigsaw or circular saw
  • Measuring tape
  • Sink braces
  • Hacksaw
  • Plumbing materials
  • Adjustable wrench

Measure The Sink

If you’re working with an existing sink cutout, make sure you buy a cast iron sink that will fit in the cutout. While you could buy a larger sink than the cutout if space allows, a too-small sink won’t work for the existing cutout. 

You need to measure for the sink hole if you’re starting fresh. The hole should be as small as possible while still allowing the sink to slide through. This offers more support for the sink itself. 

Start by measuring the lip of the sink from the underside (easier to do with the sink upside down). Measure the distance between the outside of the lip and the inner lip. Next, trace a hole that distance inside the hole you trace around the sink. Use chalk to trace the holes, as it’ll wipe away easily (on most countertop surfaces).

Ensure the hole is square and level to the sides of the countertop. Make sure the placement allows supports as necessary via anchors or a frame inside the counter. If you’re using sink anchors, align the sink with the wall studs.

Cut The Hole


The next step in the process involves cutting the hole for the sink. If you have stone countertops, like quartz or granite, it’s usually best to have a professional countertop. The same concept applies if you have glass countertops. 

If you have laminate counters, make sure you cut from the top, as the laminate may chip outward if you don’t. 

Generally, it’s best to use a rotary saw or skill saw to make the long straight cuts around the sink. If you have a curved surface, a jigsaw is the better option. Use a spade bit to cut a circular hole near the edge of the soon-to-be cutout. 

Use the hole to insert the jigsaw blade. As you cut, go slowly around the corners, careful not to overshoot them. If you drill a hole with the spade bit on each side of the cutout, this will give you a better approach to corners.

If you’re cutting wood, laminate, or composite, try to do so in a ventilated space. Wear safety glasses and a face mask rated for the job.

Install Supports And Place The Sink

If you want to install extra supports, this is the time to do them. This part varies from one scenario to the next since every case is different. If you choose to install a frame, you’ll need to design it based on the sink and its depth and the cabinet, its structure, and its frame. 

Or, install sink braces, which is a fairly straightforward process. Once the braces or frame are in place, maneuver the sink into position. You may need a friend to help you safely lift the sink and lower it into place. 

Generally, it’s easier to install the basket strainer and a faucet before moving the sink into place. So, mount the strainer and clear any debris from the drain hole to ensure everything drains properly. Use plumber’s putty to create a watertight seal. 

Connect The Plumbing

Under Sink Plumbing

With the sink in place, you need to hook up the plumbing. Before you do so, make sure you can legally install the plumbing in your home. Some areas restrict plumbing projects to licensed professionals, so double-check this isn’t the case. 

If you can install the plumbing yourself, install the plumbing beneath the sink and hook up the water lines to the faucet. Once you’re done, tighten the connections with an adjustable wrench. 

Check Your Handiwork

Check your work after you finish installing the sink, plumbing, and faucet. Run the water and check for leaks. Let water rest in the sink for about half an hour to ensure the trap doesn’t leak. If everything checks out and the sink drains correctly, your sink is fully installed. 

What Holds A Drop-In Sink In Place?

Drop-in kitchen and bathroom sinks are some of the easiest sinks to install. The sink has a lip that rests on the kitchen countertop, which helps support the weight of the sink. Hidden metal clips located under the counter hold the drop-in sink in place. However, not all drop-in sinks require metal clips – it depends on the particular sink.

In addition, a bead of silicone caulk under the sink’s edge helps prevent water from leaking into the cabinet below and helps keep the sink in place. 

Do Cast Iron Sinks Need Clips?

Serene Valley Topmount Sink Clips, Sink Brackets and Supports, Top mount Kitchen Sink Clips NSA103 - Heavy-Duty 10pcs Kit

Given the sheer weight of cast iron sinks, clips aren’t usually necessary. With that said, you will need to caulk under the lip of the sink before you set it. In some cases, folks may choose to place clamps on the sink until the silicone cures, but that is up to you. 

Do Cast Iron Sinks Need Extra Support?

Cast iron sinks are pretty hefty, much more so than many other sink materials. In some cases, extra support may be necessary, but not always. With that said, it doesn’t hurt to incorporate extra supports just in case the structural integrity of the countertop fails. 

Some countertops may not be strong enough to handle the weight of a cast iron kitchen sink, so you might want to consider installing supports.

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