Topmount Sink Installation Guide

One of the chief advantages of a topmount sink is that it is very easy to install once the sink opening has been cut.

For most drop-in sink installation, you’ll need just a few tools and materials:

  • Sink installation instructions from the manufacturer
  • Clamps or anchors included with the sink
  • A power driver or screwdriver
  • Silicone caulk

For heavy sinks that require additional support, plywood and/or dimensional lumber to build supports are needed.

kitchen sink installation

Installing a Topmount Kitchen Sink

This how-to guide will help you accomplish the installation or understand what needs to be done if you hire a professional installer.

Read the instructions included with the sink to get an overview of what needs to be done

  • Clean the underside of the sink rim and the countertop where it will rest with denatured alcohol
  • Run a ¼” bead of caulk around the top edge of the countertop where the sink will sit
  • Install the sink through the opening, and press it down firmly to create a good seal with the caulk
  • Tip: Having someone support the sink from below as you install it through the sink hole, especially if the sink is heavy, will prevent damage to the countertop, pinched fingers or disturbance to the caulk bead
  • Install and finger tighten the clamps
  • When they’re all snug, tighten them slightly more with your screwdriver or driver until the sink is secure
  • Tip: If you’re installing fastener screws into natural stone, pre-drill the holes but use a drill stop to prevent drilling through the countertop
  • Install any additional supports needed for a heavy sink
  • Install the garbage disposer, if applicable, and attach the drain
  • Install accessories such as dishwasher lines or a tankless water heater

The Cost to Install a Topmount Sink

This sink is generally included in the total cost of a kitchen remodeling project. If you have it done separately, expect this price range:

Drop-in kitchen sink installation: $75-$400

If the sink has one drain and no accessories, your estimates will be on the lower part of the range. Additional drains for a double or triple sink, a garbage disposal or dishwasher lines will all raise the cost toward the upper end of the range given.

Topmount Kitchen Sink Installation

This brief Q&A provides additional important information.

I’m adding a garbage disposal and a tankless water heater. How much will installation cost for those appliances?

The disposer should raise the cost of sink installation by $40-$75. Installing an electric tankless heater when a plug is already installed beneath the sink will add $75-$200 to the cost. If an electric line needs to be installed, the cost will be significantly higher, as it will be if running a gas line for a gas unit.

What types of sink require extra support?

Any sink that is full of dishes and water will be quite heavy, so many installers suggest adding support to any sink. However, those for which additional support is crucial include cast iron, steel, fireclay, porcelain, granite composite and similar materials.

How are the extra brackets installed?

Ask your sink retailer about the specific requirements for your sink. The strongest supports extend to the sink cabinet floor rather than attaching to the cabinet walls. See our Farmhouse Sink Installation Guide for more details.

Can a topmount sink be installed in place of an apron sink?

Not without modification to the countertop. With drop-in sink installation, the countertop surrounds the sink. With apron sink installation, there is no countertop material at the front of the sink. Something would have to be fabricated, and the likelihood it would look proper isn’t very good. The cost would be significant too.

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