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Top 3 Undermount Sink Installation Techniques For Granite & Quartz

August 3, 2018

Granite Countertops
Andy Coleman

Published by Andy Coleman

Have you ever wondered what holds an undermount sink in place when installed under a granite or quartz counter top?

If so, read on! The following article explains in detail the 3 most effective undermount sink install techniques used on Stainless Steel, Composite, and Cast Iron or Clay sinks.

Sink Clips

Stainless Steel and Composite sink manufactures provide a system for attaching directly to the underside of the G/Q counter top.  The system includes 6-8 bolts, clips, and wing nuts.

The bolts are inserted into grooves that the fabricator drills or cuts into the back of the counter, spaced evenly around the flange of the sink.  The clip is then attached to the flange and tightened to secure the sink to the counter top.

Sink Rails

For extremely heavy and uneven cast iron and clay sinks, a rail system is necessary so the cabinet supports the weight not the counter top.

Two rails are attached to the front and back of the sink cabinet on the left and right side of the sink with enough space for the sink to be adjusted to the final placement of the polished opening in the granite or quartz countertop.

Then the leveling feet are adjusted to raise the top of the sink into contact with the bottom of the counter to minimize the caulk gap.

Cabinet Brackets

These are plastic devices that are generally used to repair a sagging sink that failed because the fabricator took shortcuts and didn’t use sink clips or rails.

Four to six hinged brackets push the flange of the sink against the bottom of the granite or quartz counter and are then screwed into the wall of the cabinet to hold it in place.

Gravity, moisture, and the vibration of a garbage disposal create a shocking amount of stress on an under mount sink installation, so make sure the fabricator you hire for your granite or quartz project uses clips, rails, or brackets instead of a shortcut!

Learn more about undermount sinks in our blog, Undermount Sink Failure In Granite And Quartz

Are you considering new countertops for your kitchen but not sure where to start? Our free Countertop Buying Guide has all the information you need to make the best decision for your style, budget, and needs.

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Tags: Granite Countertops, Crowley's Process, Quartz Countertops