ANATOMY OF A FLOOR
When most of us think of a floor we envision the top layer: in effect, the
decorative covering -- hardwood, ceramic tile, laminate, or carpet. The
“real” floor is hidden underneath.
Your floor is made of a sturdy plywood or composite panel subfloor that
spans supportive floor joists. The subfloor may be large sheets or planks
(and the planks may be arranged in a staggered or diagonal fashion). The
joists sit on sills along the foundation and are often sup ported at a
midpoint by a steel girder or wood beam.
An elevated framed floor, like the one shown above, is supported by beams
that run perpendicular to the joists. In most cases, the joists are tied
together with bridging for extra stability (see photo next page, lower
Depending on the type of flooring used, the subfloor may be covered with an
additional layer of underlayment, such as a cement board The top layer of
flooring is installed on the underlayment or subfloor and may rest on some
type of cushioning layer. Of course, there are always custom options, such
as soundproofing or heating, that may be layered into your floor plan. It’s
important to know what is under your floor covering and how your floor is
sup ported before starting any repairs on that floor.