and may vary from 2 to more than 16 feet. The top is
slightly wider than the bottom so that tight joints result
when flooring is laid. The tongue fits tightly into the
groove to prevent movement and floor squeaks.
Thin strip flooring (fig. 6-1. view B) is made of 3/8-
by 2-inch strips. This flooring is commonly used for
remodeling work or when the subfloor is edge-blocked
or thick enough to provide very little deflection under
loads.
Square-edged strip flooring (fig. 6-1, view C) is
also occasionally used. The strips are usually 3/8 inch
by 2 inches and laid over a substantial subfloor.
Face-nailing is required for this type of flooring.
Plank floors are usually laid in random widths. The
pieces are bored and plugged to simulate wooden pegs
originally used to fasten them in place. Today, this type
of floor has tongue-and-groove edges. It is laid similar
to regular strip flooring. Solid planks are usually
3/4 inch thick. Widths range from 3 to 9 inches in
multiples of 1 inch.
Figure 6-2.—Application of strip flooring.
Installation
Flooring should be laid after drywall, plastering, or
other interior wall and ceiling finish is completed and
dried out. Windows and exterior doors should be in
place, and most of the interior trim, except base, casing,
and jambs, should be installed to prevent damage by
wetting or construction activity.
Board subfloors should be clean and level and
covered with felt or heavy building paper. The felt or
paper stops a certain amount of dust, somewhat deadens
sound, and, where a crawl space is used, increases the
warmth of the floor by preventing air infiltration. As a
guide to provide nailing into the joists, wherever
possible, mark with a chalk line the location of the joists
on the paper. Plywood subflooring does not normally
require building paper.
Strip flooring should normally be laid crosswise to
the floor joists (fig. 6-2, view A). In conventional
structures, the floor joists span the width of the building
over a center-supporting beam or wall. Thus, the finish
flooring of the entire floor areas of a rectangular
structure will be laid in the same direction. Flooring with
“L”- or “I’’-shaped plans will usually have a direction
change, depending on joist direction. As joists usually
span the short way in a room, the flooring will be laid
lengthwise to the room. This layout has a pleasing
appearance and also reduces shrinkage and swelling of
the flooring during seasonal changes.
Storing
When the flooring is delivered, store it in the
warmest and driest place available in the building.
Moisture absorbed after delivery to the building site is
the most common cause of open joints between flooring
strips that appear after several months of the heating
season.
Floor Squeaks
Floor squeaks are usually caused by the movement
of one board against another. Such movement can occur
for a number of reasons: floor joists too light, causing
excessive deflection; sleepers over concrete slabs not
held down tightly; loose fitting tongues; or poor nailing.
Adequate nailing is an important means of minimizing
squeaks. Another is to apply the finish floors only after
the joists have dried to 12-percent moisture content or
less. A much better job results when it is possible to nail
through the finish floor, through the subfloor, and into
the joists than if the finish floor is nailed only to the
subfloor.
Nailing
Various types of nails are used in nailing different
thicknesses of flooring. Before using any type of nail,
you should check with the floor manufacturer’s
6-2
