Framing, in construction known as light frame construction, is a building technique
based around structural members, usually called studs, which provide a stable frame
to which interior and exterior wall coverings are attached, and covered by a roof
comprising horizontal ceiling joists and sloping rafters (together forming a truss
structure) or manufactured pre-fabricated roof trusses—all of which are covered by
various sheathing materials to give weather resistance.
Modern light-frame structures usually gain strength from rigid panels (plywood and
other plywood like composites such as OSB) used to form all or part of wall sections,
but until recently carpenters employed various forms of diagonal bracing (called
"wind braces") to stabilize walls. Diagonal bracing remains a vital interior part
of many roof systems, and in-wall wind braces are required by building codes in many
municipalities or by individual state laws in the United States.
Light frame construction using standardized dimensional lumber has become the dominant
construction method in North America and Australasia because of its economy. Use
of minimal structural materials allows builders to enclose a large area with minimal
cost, while achieving a wide variety of architectural styles. The ubiquitous platform
framing and the older balloon framing are the two different light frame construction
systems used in North America. Wall framing in house construction includes the vertical
and horizontal members of exterior walls and interior partitions, both of bearing
walls and non-bearing walls. These "stick" members, referred to as studs, wall plates
and lintels (headers), serve as a nailing base for all covering material and support
the upper floor platforms, which provide the lateral strength along a wall. The platforms
may be the boxed structure of a ceiling and roof, or the ceiling and floor joists
of the story above. The technique is variously referred to colloquially in the building
trades as "stick and frame" or "stick and platform", or "stick and box" as the sticks
(studs) give the structure its vertical support, and the box shaped floor sections
with joists contained within length-long post and lintels (more commonly called 'Headers'),
supports the weight of whatever is above, including the next wall up and the roof
above the top story. The platform, also provides the lateral support against wind
and holds the stick walls true and square. Any lower platform supports the weight
of the platforms and walls above the level of its component headers and joists.
Framing lumber should be grade-stamped, and have a moisture content not exceeding
19%.
There are three historically common methods of framing a house. Post and Beam, which
is now used predominately in barn construction. Balloon framing using a technique
suspending floors from the walls was common until the late 1940s, but since that
time, platform framing has become the predominant form of house construction. Platform
framing often forms wall sections horizontally on the sub-floor prior to erection,
easing positioning of studs and increasing accuracy while cutting the necessary manpower.
The top and bottom plates are end-nailed to each stud with two nails at least 3 1/4
in. (82 mm) in length (16d or 16 penny nails). Studs are at least doubled (creating
posts) at openings, the jack stud being cut to receive the lintels(headers) that
are placed and end-nailed through the outer studs.
Wall sheathing, usually a plywood or other laminate, is usually applied to the framing
prior to erection, thus eliminating the need to scaffold, and again increasing speed
and cutting manpower needs and expenses. Some types of exterior sheathing, such as
asphalt-impregnated fiberboard, plywood, oriented strand board and waferboard, will
provide adequate bracing to resist lateral loads and keep the wall square, but construction
codes in most jurisdictions will require a stiff plywood sheathing. Others, such
as rigid glass-fibre, asphalt-coated fiberboard, polystyrene or polyurethane board,
will not. In this latter case, the wall should be reinforced with a diagonal wood
or metal bracing inset into the studs. In jurisdictions subject to strong wind storms
(Hurricane country, tornado alleys) local codes or state law will generally require
both the diagonal wind braces and the stiff exterior sheathing regardless of the
type and kind of outer weather resistant coverings.
.jpg)
.jpg)