Hello Friends,

Undermount sinks are secured to the underside of the counter and must have caulk applied to create a waterproof seal. This will require you apply caulk to the sink before and after it is set in place. The caulk prevents water from seeping through the seam between the countertop and the sink. Caulk an undermount sink by first checking to make sure the sink will sit flush with the bottom of the counter. Run a bead of caulk along the top or lip of the sink that will sit against the bottom of the counter.

Thanks and Regards
John marrison