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 oriented strand board (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 Australia 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, 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.
A typical modern wood-frame house consists of a reinforced concrete strip-footing foundation, whereupon a platform is constructed of joists covered with plywood or oriented strand board (OSB) to form the ground-floor level of the house (also known as platform wood-frame construction). This platform is connected directly to the foundation with anchor bolts. On this base, the exterior and interior walls are erected. The walls consist of a horizontal sill plate with vertical timber studs with board or panel sheathing nailed to the studs on the outside of the building. After the first-story walls are completed, the second-story floor is constructed, which, in turn, acts as a platform for erection of the second-story walls. This process is continued for all the stories. The roof structure typically consists of prefabricated trusses, which are covered with sheathing and roof tiles.
The standardized wood-frame structure of today is now augmented by a wide range of compatible standardized components, such as doors, windows, electrical and plumbing fixtures, and the like, which are designed to be easily installed in the wood structure.
Because wood-frame walls are hollow, alternative levels of insulation can be installed enabling any climatic conditions to be accommodated. Plumbing, heating, and electrical services are easily installed within the walls, in the open spaces above ceilings, within the floor structure, and in the space between the first (ground) floor and the ground below. Wood-frame houses can be up to three stories in height.
Today, wood frame is used for approximately 90% of the houses constructed in the USA, predominantly in suburban regions. Costs vary greatly by region and house design, and range from about 650 US$/m2 to 2200 US$/m2, excluding land cost.
In the typical wood frame house, gravity loads are accommodated by wood “studs,” commonly placed at 16 inches (approximately 400 mm) centers. Floor and roof-framing members are commonly 2 inches (50 mm) in thickness and may be from 6 to 14 inches (150 mm to 350 mm) in depth. Lateral resistance is provided by a shear-wall system consisting of plywood or manufactured wood panels (particle board) nailed to vertical studs, creating shear walls.
Wooden posts, with cross-sectional dimensions ranging from 105 mm to 150 mm, carry gravity loads. The roof structure is made out of wood and is covered by roof tile or slate. The roof load is transferred to the wood frame. The roof-supporting system in Japan is different from that of western countries and is based only on vertical and horizontal members. No diagonal members or trusses are used, as is common for similar construction in Western countries.
Alternate approaches to the post-and-beam construction are the Russian Federation’s timber panel construction and horizontal timber log construction. The panel buildings use load-bearing panel walls to carry gravity loads. The layered paneling acts as a shear wall to resist lateral loads. These layered timber panels also serve as floor and roof diaphragms. The horizontal timber system uses stacked logs as vertical and lateral load-resisting elements.
b) Read the text again and make a list of additional topical vocabulary (10 to 15 words and word-combinations). Consult a dictionary to finalise the choice of the Russian equivalents. Memorise the new vocabulary.
Project“Wood and Wood-Based Materials”
Divide into teams of 4 or 5 students. Choose any aspect of the problem of the forest disturbances. Jointly arrange a presentation of the materials collected in form of PowerPoint demonstration. Try to illustrate your points of presentation.
Suggested issues:
Is wood as popular now as it was in the previous centuries? Speak about the applications of wood as a structural and secondary building material. Discuss the advantages and disadvantages of wood and wood-based materials in domestic construction.
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