Kohler 27121-4-SN Guide D'installation page 4

Prepare the Site (cont.)
For a finished bath deck/rim less than 5/8" (16 mm) thick: Install
wood reinforcement to the underside of the deck/rim. The
combined thickness of the reinforcing material and the deck/rim
must not exceed 3" (76 mm).
NOTICE: Do not exceed 1-1/2" (38 mm) hole diameters for the
spout and valve body mounting holes. Maximum contact area is
necessary for a successful installation.
Carefully cut mounting holes for the spout and valve bodies.
Install or relocate the water supplies as needed.
1347030-2-A 4 Kohler Co.