Framing (construction)
Light-frame construction using standardized dimensional lumber has become the dominant construction method in North America and Australia due to the economy of the method; use of minimal structural material allows builders to enclose a large area at minimal cost while achieving a wide variety of architectural styles.
Modern light-frame structures usually gain strength from rigid panels (plywood and other plywood-like composites such as oriented strand board (OSB) used to form all or part of wall sections), but until recently carpenters employed various forms of diagonal bracing to stabilize walls.
The platform also provides lateral support against wind and holds the stick walls true and square.
In some countries, framing lumber is subject to regulated standards that require a grade-stamp, and a moisture content not exceeding 19%.
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 (construction codes in most jurisdictions require a stiff plywood sheathing).
[11] In jurisdictions subject to strong wind storms (hurricane countries, 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.
A multiple-stud post of at least 3 three studs, is generally used at exterior corners and intersections to secure a good tie between adjoining walls.
These members, referred to as studs, wall plates and lintels, serve as a nailing base for all covering material and support the upper floors, ceiling and roof.
This spacing may be changed to 12 or 24 inches (300 or 610 mm) on center depending on the load and the limitations imposed by the type and thickness of the wall covering used.
This spacing may be changed to 12 or 24 in (300 or 610 mm) depending on the loads supported and the type and thickness of the wall finish used.
[12] Lintels (or, headers) are the horizontal members placed over window, door and other openings to carry loads to the adjoining studs.
[4] Lintels are usually constructed of two pieces of 2 in (nominal) (38 mm) lumber separated with spacers to the width of the studs and nailed together to form a single unit.
Lintels are predominately nailed together without spacers to form a solid beam and allow the remaining cavity to be filled with insulation from the inside.
The complete wall sections are then raised and put in place, temporary braces added and the bottom plates nailed through the subfloor to the floor framing members.
Norman Isham wrote, "sometimes the frame was covered with vertical boarding applied to the sills, plates, and girts without any intermediate framing, but in a greater number of houses the spaces between the heavier timbers are filled with lighter vertical sticks called studs.
"[16] The growth of a nail-making industry in the early 19th century made the frame even faster to assemble, with some of the first machines developed in the late 1700s in Massachusetts.
However, the first building using balloon framing was possibly a warehouse constructed in 1832 in Chicago, Illinois, by George Washington Snow or Augustine Deodat Taylor.
Robinson's system called for standard 2×4 lumber, nailed together to form a sturdy, light skeleton.
[27] It is also likely that, by radically reducing construction costs, balloon framing improved the shelter options of poorer North Americans.
Light frame material dimensions range from 38 by 89 mm (1.5 by 3.5 in); i.e., a Dimensional number two-by-four to 5 cm by 30 cm (two-by-twelve inches) at the cross-section, and lengths ranging from 2.5 metres (8.2 ft) for walls to 7 metres (23 ft) or more for joists and rafters.
architects have begun experimenting with pre-cut modular aluminum framing to reduce on-site construction costs.
Wall panels built of studs are interrupted by sections that provide rough openings for doors and windows.
Diagonal bracings made of wood or steel provide shear (horizontal strength) as do panels of sheeting nailed to studs, sills and headers.
[citation needed] Interior wall coverings in light-frame construction typically include wallboard, lath and plaster or decorative wood paneling.
[citation needed] In natural building, straw bales, cob and adobe may be used for both exterior and interior walls.
A light-frame structure built mostly inside sloping walls which also serve as a roof is called an A-frame.
In North America, roofs are often covered with shingles made of asphalt, fiberglass and small gravel coating, but a wide range of materials are used.
Light-frame buildings in areas with shallow or nonexistent frost depths are often erected on monolithic concrete-slab foundations that serve both as a floor and as a support for the structure.
Engineered components are commonly used to form floor, ceiling and roof structures in place of solid wood.
