The Woodwork Institute is a national organization whose primary purpose is to ensure excellence and craftsmanship in woodwork. The WI collaborates with the Architectural Woodwork Manufacturers Association of Canada to jointly sponsor the North American Architectural Woodwork Standards (NAAWS). Architects and millwork firms rely on this proven standard as the basis for quality architectural millwork.

The WI defines cabinet surfaces as follows:

SURFACE TERMINOLOGIES
Cabinet surfaces are defined in four distinct
categories, three for exposed surfaces with very
specific minimum surface requirements and one
for concealed surfaces subject to manufacturer’s
choice, as follows:
EXPOSED EXTERIOR SURFACES, defined as
all exterior surfaces exposed to view, including:
• All surfaces visible when doors and drawers
are closed, including knee spaces.
• Underside of cabinet bottoms over 42” (1067
mm) above the finished floor, including
cabinet bottoms behind light valances and
the bottom edge of light valances.
• Cabinet tops under 80” (2032 mm) above
the finished floor, or if 80” (2032 mm) and
over and visible from an upper building level
or floor.
• Front edgeband of stretchers, ends,
divisions, partitions, fixed shelves, tops, and
bottoms.
• Front edgeband of adjustable shelves
exposed to view in open casework or behind
transparent doors.
• Sloping tops of cabinets that are visible.
EXPOSED INTERIOR SURFACES, defined as
all interior surfaces exposed to view in open
casework or behind transparent doors, include:
• Interior faces of shelves (both fixed
and adjustable), divisions and partitions
(edgeband is an Exposed Exterior Surface).
• Interior face of ends (sides), backs, and
bottoms (including pull outs).
• (914 mm) or more above the finished floor.
• Interior face of doors and applied drawer
fronts.
SEMI-EXPOSED SURFACES, defined as
those interior surfaces only exposed to view
when doors or drawers are opened, include:
• Interior faces and edgeband of adjustable
shelves, except at Premium Grade where
edgeband shall match Exposed Exterior
surface.
• Divisions and partitions (edgeband is an
Exposed Exterior Surface).
• Interior face of ends (sides), backs, and bottoms
(including a bank of drawers).
• Interior face of cabinet top members 36”
(914 mm) or more above the finished floor.
• Drawer box sides, sub fronts, backs,
edgebanding, and bottoms.
• The underside of cabinet bottoms between
24” (610 mm) and 42” (1067 mm) above the
finished floor.
• Security and dust panels or drawer
stretchers.
CONCEALED SURFACES, defined as those
exterior or interior surfaces that are covered or
not normally exposed to view including:
• Toe space unless otherwise specified.
• Sleepers, stretchers, and solid sub tops.
• The underside of cabinet bottoms less than
24” (610 mm) above the finished floor.
• The underside of countertops, knee spaces,
and drawer aprons.
• The flat tops of cabinets 80” (2032 mm) or
more above the finished floor, except if visible
from an upper floor or building level.
• The three non visible edges of adjustable
shelves.
• The underside of countertops, knee spaces,
aprons and drawer boxes that are less than
36” (914 mm) above the finished floor.
• The faces of cabinet ends of adjoining units
that butt together.