Installation Guide

8/19/2022Revised
Installation / Installation / Instalación
Undermount sinks are sinks that are attached from below the countertop. These instructions are for installing 1858
Brand undermount stainless steel sinks in a solid surface countertop only. The minimum thickness of the actual
countertop material is one half-inch. In addition, a one-inch build-up around the sink is preferred. The manufacturer
recommends that undermount sinks and routering of your solid surface material should be installed by a professional
installer for best results. Requirements vary for installation in a granite, marble, stone, or butcher block countertop.
There are three ways an undermount sink can be installed; Positive Reveal, Flush, or Negative Reveal. Each different
reveal creates a distinctive look where the countertop and sink meet (see diagram below).
Positive Reveal - The countertop edge sits approximately 1/4” back from the edge of the sink, exposing the sink rim.
All 1858 brand undermount sinks feature a 1-inch finished rim. All 1858 brand undermount sinks feature an
approximate 1/4” positive reveal.
Undermount
Stainless
Steel Sinks
Flush - The countertop meets the edge of the sink. Fitting flush with the sink bowls
Negative Reveal - The countertop extends over the edge of the sink on all sides by approximately 1/4”. Use caution
with this installation to be sure that accessories such as colanders or cutting boards will fit properly.
1858 Brands recommends that all countertops be cut by an approved or certified installer and that
the sinks be installed by the installer whenever possible. The countertop/sink unit ideally should be
installed as one on the job site. Please carefully read all instructions before beginning installation.